How to Measure EMF

by / Thursday, 30 May 2013 / Published in Healthy Building Inspections & Testing
ElectroMagnetic EMF Spectrum

How to Measure EMF: The Art of Knowing What You Are Studying

There are a lot of people out there concerned about electromagnetic fields (EMF) and electromagnetic radiation (EMR or also known as radio frequency (RF)).  People want to know how to measure EMF. So much so, that they purchase detectors and meters for themselves and attempt to study their own property and homes.  It is great to take responsibility for your own concerns! However, there are likely many things that could be confusing your personal assessment.

How to Measure EMF

ElectroMagnetic EMF Spectrum

The electromagnetic spectrum is organized by frequency. Generally lower frequency radiation is on the left, and higher frequency radiation is on the right. See above graphic.

The properties of electromagnetism change at different frequencies, and electric and magnetic fields behave differently along the spectrum.  A material that is transparent to visible light can be opaque to infrared light, but then again transparent to radio frequency radiation (e.g., glass).  Chrome is highly reflective to all of these frequencies, but nearly invisible to IR cameras because it reflects much more heat energy than it emits.  So how do you measure the temperature of a chromed device if you cannot attach temperature sensors (thermocouples) to it?

How to Measure EMF

EMF Meter Should Detect Hot Spots – Magnetic Fields Near Electrical Panel. [Measuring 157 milliGauss (mG)]

Measuring Magnetic Fields

Meters measuring magnetic fields strength analyze the flux (changing field properties) of the magnetic field.  A meter in motion will not measure this accurately, because measurements will be artificially elevated as you move through a magnetic field.   While an accurate quantitative measurement cannot be made while moving, a qualitative measurement can be made to show places where more investigation is recommended. Walking through a building with a magnetic field meter taking real-time measurements is still an effective strategy of finding “hot spots.”

Measuring Radio Frequency (RF) Radiation

Higher than expected radio frequency (RF) power density can be just as confusing. RF can act sort of like X-rays, penetrating through many materials, reflecting off others.  This can produce apparently high power densities in certain areas and make finding the source of those RF radiations more difficult. Using separate RF meters or antennas with the capability of omni-directional AND more focused targeting can be useful in this regard.

How to Measure EMF

David Sasse using Directional RF Antenna at Smart Meter

How to Measure EMF

Alex Stadtner Using Omni Directional RF Antenna at PV Inverter w: Wireless Signal

If you find areas that raise your concerns it is best to refer to an expert in the field – much like a medical generalist refers to a specialist.  A qualified EMF specialist is trained specifically in the use of high quality equipment, has area-specific knowledge, and has experience with many different buildings and situations.

EMF Testing Services

If you bring your EMF concerns to Healthy Building Science, it usually makes our jobs easier by giving us a heads-up as to where to start our investigation.  Don’t be surprised if our investigation brings unforeseen conclusions! Often we deliver better than expected news and peace of mind, and no additional measures are recommended or the fix is more simple than you think.

How to Measure EMF

Author (Cameron Das) Performing Diagnostics for EMF Wiring Errors – DO NOT TRY THIS AT HOME

135 Responses to “How to Measure EMF”

  1. Alex Stadtner says :

    You should probably call the company you purchased your EMF meter from and ask them how to use it. Or consider attending a Building Biology seminar or hiring a Building Biologist who can show you what the readings mean. I don’t even know what units you’re referring to – so absent that and an onsite EMF inspection I cannot give you any insight.

  2. Jessica says :

    I’m using a Cornet Electrosmog meter. What does it mean if the readings are green .001-.002 but flash into yellow about every 10-20 seconds .030? I’ve identified most of the large “RED” issues and unplugged them, but can’t figure out what is causing these pulses. I tried turning off the breakers to the rooms. Our Wi-Fi is off and we are pretty rural. I do pick up one or two distant Wi-Fi signals. Any thoughts?

  3. Alex Stadtner says :

    Haven’t seen any third-party reviews or formal studies. Don’t know it. With meters you tend to get what you pay for.

  4. Teresa hatfield says :

    Is the app EMF Detector trustworthy?

  5. Alex Stadtner says :

    We’re working on creating a products page that will include mid-range recommended EMF meters. Personally, I use the GigaHertz Solutions NFA 1000, but that’s more than most entry-level EMF inspectors will need. We’re working on a list and I’ll post it here once it’s posted.

    RF meters work by attracting RF via an attached antenna and measuring it’s relatively level. I don’t know the details of how that happens – but every RF meter has a built-in or external antenna. In some situations, especially with electric fields, the user can become an antenna and impact the readings. This is true with RF, too, but usually it’s less observable compared to extremely low frequency (ELF) electric fields. I have very little faith in the Trified so I might guess it’s being confused by electric fields if your RF is spiking when you touch a nearby cord.

    Wireless alarm contacts for fire or security, wireless phones and baby monitors, cell phones and wireless routers, all have different emissions rates. So there is no one answer for how much any given source is supposed to emit. In my limited experience with the Trifield is will only spike when very near a source. I’d suggest using a Trifield device as a “detector,” not an EMF meter to make precise measurements.

  6. Eleven Eleven says :

    I read your comment about the Trifield 100XE meter however that is what I have been utilizing and relying upon. What other option do you recommend that is priced reasonably?
    I can’t attest to the accuracy despite feeling strong RF and magnetic fields which my meter does attest to. How do such meters detect RF? cause I read it uses your body which makes since as sources are always very high when I hold it opposed to setting it down next to a source. For example right now my laptop or ethernet cord holding with 1 or 2 hands reads .4 which is always does later in the day opposed to AM. Any insight why that could be? Also do you know how high RF fire alarm systems are supposed to read running thru the walls near outlets cause the rf is everywhere and against my body its even higher which I thought strange as I mostly only see that holding it near metal surfaces.
    Thanks for your time.

  7. kris says :

    i heard that trifled meters cannot pick up digital radio frequency only analogue which means they cant ready cell phone signal

  8. Alex Stadtner says :

    The Trifield EMF meters are notoriously inaccurate. In my opinion you should use it like a detector (noise maker) and not a meter (sophisticated measuring machine). If you’re in the “electric” setting and it’s spiking near a wall – then 99% chance it’s Romex (unshielded wire) and that’s the source of electric fields in the vicinity. Try turning off the circuits that service that area. If your meter no longer registers electric fields then you know you’ve identified the source. Good luck.

  9. JL says :

    Hello and Greetings from Scotland. Thank you very much for all the information; I’ve read through everything here, but I do not think I can see the answer to my question so here goes. I’m looking at buying a house. During the viewing I had my Trifield (UK/Europe model) with me and on the electric setting I was not getting any readings in any room until I touched/nearly touched some of the walls, at which time the meter would shoot up to 50% all the way to nearly full. I take it this is from the wiring. So my questions are – was I using the Trifield incorrectly (does holding it so close to an object- this case the wall- create misrepresentative readings) and is this typical/do I have anything to be concerned about? Away from the walls there was no reading on any of the settings with the exception of being close to the router. Thank you.

  10. Alex Stadtner says :

    Can’t speak to the “danger” aspect, but you’re correct that if the home is properly wired and the main house drop-down (connection to utility) is the primary source… the level of magnetic fields should decrease as you get further from the “source.”

  11. Douglas says :

    Hi Alex,

    Our bed is in the corner of the house where the electrical connects to the corner of the house from the street. If the emf drops off before it hits our bed is there any danger?

    Thanks ,


  12. Alex Stadtner says :

    There are private firms, such as Healthy Building Science, that offer EMF testing and remediation recommendations. It can get tricky if the school doesn’t allow access, but generally they will open their doors to a private survey if it’s paid for by a parent or other concerned party. Find a building biologist to help you out.

  13. Kris says :

    I am interested in learning about the emissions from an Eversource solar farm going in directly across from a school campus. My son’s school is approximately 1700 ft from the solar farm. I spoke with an ES Rep and I was told that the EMFs are estimated to be 2-4 mg and I also called an EMF hotline. The hotline wasn’t very helpful. I asked where the inverter would be located and that couldn’t be determined. The other question that I had was will an EMF field test study at the school sites be done after the farm is up and running to determine the EMF emissions. I was told that an EMF test would be done only if the school asked for it. That is important information that I feel should be provided to the schools without the schools asking for it. If the school isn’t willing to have the test done is there another source that could do the test?

  14. Alex Stadtner says :

    Typically TV antenna are “receivers” and not “transmitters.” So unless your building is a TV studio transmitting and broadcasting a signal I wouldn’t expect it to be a problem. That said – where there are TV antenna there are often cellular antennas. The only way to know for sure is to have an EMF survey performed.

  15. N.N says :

    We are staying on 9th floor in 10 story building. On tarace( means 2 floor up we have roof) there are somany TV Antenna.
    How to measure Tv Antenna Radiation? Is it harmful for us?

  16. Alex Stadtner says :

    Purchase a gauss meter (magnetic field meter) or hire an EMF expert to perform an EMF testing at the property.
    It’s hard to say without having real measurements. Good luck!

  17. Anuja says :

    Hi Alex,
    I am interested to buy a property. I noticed that there is an overhead powerline (110KV) over the neighbour’s house. this house might be 15-20 feet away from the property I am interested in. The closest pylon connecting these powerline is 3-4 houses away. I have a 10 years old child and bit concerned about the health effect of living in the proximity of 110kv powerline. Any comment or suggestion would be helpful. thanks

  18. Alex Stadtner says :

    Hello Joe,
    Your level of concern should come from a combination of understanding health impacts from EMF and the exposure level and duration in your home. To determine the exposure level you should consider hiring a Building Biologist or purchasing EMF meters and performing your own assessment. I would say that a transformer 15 feet away MAY or MAY NOT have have measurable impact. It depends on the design of the transformer and the load (amperage) pulsing through it. It is in the range that I would suggest you investigate further.
    Best of luck,

  19. joe says :

    How concerned should we be by the residential transformer 15 feet in front of our house?

  20. Alex Stadtner says :

    Another great source on EMF – for both meters and locating EMF testing experts – is Lloyd Burrell’s site: ElectroSense

  21. Alex Stadtner says :

    We are unaware of meters and software that would enable mapping of DC magnetic fields. Sounds like an interesting project. Would be great to cross-reference with dowsing, as many believe it’s DC EMF that dowers pick up on. Good luck.

  22. Naseer says :

    I want to create a 2D map of dc magnetic field emnating from few wires running in parellel. How can I do that?

  23. Alex Stadtner says :

    Oh brother. We get asked this all the time… and we really should have a better answer. But in the years since induction cooking has been around I haven’t seen a single study or comparison or even “best practices” regarding electromagnetic fields (EMF) and these devices. Sorry – it’s just a big unknown at this time. I imagine that they’re like other electronic and resistance heating devices – and that some models produce significantly greater magnetic fields. But there is no published list or chart showing emissions rates for each model. This comes up all the time. Someday someone will probably hire us to test a few at a shop and we’ll report the findings in a blog. Until then… it’s the wild west. Get a meter or hire an EMF consultant and try to get some measurements in the store. That’s the best I can offer at this time.

  24. Alex Stadtner says :

    Congratulations on the new school. It is unfortunate they placed a playground over the power lines, but lines underground are generally located closely together and often have lower magnetic field emissions than you might expect. You’ll need an AC magnetic meter or “Gauss meter,” such as those sold through Safe Living Technologies and Less EMF. In general we suggest getting the most expensive meter you can afford – because you get what you pay for. But the representatives of these companies could give you more specific feedback on which EMF meter is best for your needs. Best of luck.

  25. Alex Stadtner says :

    Hello, DC current should be rather independent from RF. You need a DC magnetic meter that measures in tesla or Gauss, generally nanotesla (nt) and milliGauss (mG). There are many common multi-meters and clamp-on sensors to help you measure amps and volts. They, too, should be rather independent from the ambient RF environment.
    Good luck!

  26. kishore says :

    is it possible to measure the EMF Radiation in Field( Earth ) if it’s possible how many meters it will cover.

  27. Karen says :

    What can you tell me about the safety of an induction cooktop? I’m concerned about the EMF…I’m told they dissipate on such cooktop at 12″ but I’m often that close if not closer when I cook. Also, do I need be concerned that my food is on the EMF “circle”.

  28. Donald Alder says :

    Hi Alex,

    Our school district in Moose Lake, MN just built a new school, which is great. However, I am greatly concerned that they located the new playground directly over the buried power line coming into the building. As parents, what should we be testing for and what would be the best type of equipment to use?

  29. Jamshaid says :

    how to measure DC current in dense RF environment?
    I use DMM but due to high RF frequencies(Jamming device) it doesn’t work.
    Is there any special type of Ampere/Voltage meter which I can use to measure current and voltages in RF environment.
    RF power is about -10dbm.

  30. Alex Stadtner says :

    The only way to know the relative impact of all these point sources is to test them. You’d use a gauss meter for the transformer and to see if there any other point sources (e.g., electrical boxes) or wiring errors in the classroom, and an RF (radio frequency) meter to evaluate the strength of wi-fi and iPhones. Can’t say without taking measurements. Perhaps there’s a nearby Building Biologist who could perform and EMF assessment?

  31. Teresa says :


    There is a large transformer in my classroom on a second story loft. It hums loudly. It is about six feet above an average person’s head and at least 20 feet away (horizontally) from students (the closest desk is about 20 feet from it). Are we far enough away to be considered safe? We also have wireless internet, laptops, iPhones, etc. in the room close to us. Are these more of a concern than the transformer? Thanks.

  32. Alex Stadtner says :

    milliGauss (mG) is a measurement of extremely low frequency magnetic field strength, so it will not help at all when trying to measure radio frequency radiation. Aluminum foil between a source and occupant will effectively “shield” RF. But so does the back of your smart meter metallic box. Foil won’t do anything to control the magnetic fields surrounding the electrical panel. Distance or magnetic field shielding is your best bet for that. There are also some wiring techniques that will reduce the magnetic fields emanating from the panel, but that would require an electrician. Good luck.

  33. Diana says :

    I have a “K2” meter which measures in milliGAUSS. Please advise if this is suitable to measure RF emmissions from a smartmeter. I have 3 desks with bookcase/hutches against a wall where a smartmeter is installed on the outside. I have put aluminium foil on the back of the desks/hutches. Will this shield be sufficient to block radiation from the smartmeter to whoever is sitting at the desks? Thank you

  34. Alex Stadtner says :

    Hi Mark,
    We’re not doctors so we don’t attempt to guess at what’s dangerous, but you can review some peer-reviewed and published studies that may give you pause (EMF Health Effects compilation = BioInitiative Report). We measure Radio Frequency (RF) radiation with an RF meter. You can get a decent meter for $400-800, or spend several thousand on a higher end meter such as those from GigaHertz Solutions or NARDA. If you discover the levels are higher than you desire, there are almost assuredly shielding methods that could protect your work area without significantly impacting your ability to transmit a strong signal. A certified Building Biology Environmental Consultant has been trained to help in these sorts of situations, so you might check out their “find an EMF expert” page if you want an EMF Consultant.
    Best of luck,

  35. Mark Townsend says :

    I have an LPFM (low power fm) radio station which I broadcast from my work place. I broadcast at 2.5 watts @ 88.1 Mhz. Do you think being this close to the transmitter, antenna (around 8 mtrs could be a cause for concern? What is the best method for testing this type of emf? Thanks. 🙂

  36. Alex Stadtner says :

    Hi Gary,
    Interesting query. Do you have some literature that came with the pacemaker about what frequencies of EMF or Electromagnetic Radiation (EMR)? Somewhere they should mention frequencies and levels. I don’t know that particular meter, but it probably measures low-frequency electric and magnetic fields. I’d start with your pacemaker user manual and move out from there. We measure 5 different (non-visible) things within the EMF spectrum – low frequency electric and magnetic fields, dirty electricity, radio frequency (RF) radiation, and ionizing radiation. All aspects are measured with different meters and utilize different units of measurement.
    Play safe!

  37. Gary M says :

    I recently had a pacemaker implanted and just ordered and received an Electromagnetic Radiation Tester by Benetech Model GM3120. I don’t understand exactly how it works other than it has 2 functions, 1)Electrical fields and 2)H-field. I’m just trying to find out if I can use my woodshop power tools safely as well as a Duromax portable generator. Can you give me any guidance? Thanks so much!

    Gary M [email protected]

  38. Alex Stadtner says :

    Hi Phil,

    Thanks for writing in. We find that sometimes it’s harder to sell homes near the high-voltage power lines for just the concern you’re raising. 500 feet is a pretty good distance and it’s possible that there would be no (or low) influence on the background level of magnetic fields. We’re not doctors so we shy away from saying whether or not a building is safe… or what a safe level of EMF is for a family. But we often refer folks to this policy and research review document about EMF Healthy Effects.

    You could hire a local building biologist to perform and EMF inspection of the property, or you could explore purchasing your own meters from Safe Living Technologies or LessEMF (low-frequency AC magnetic fields).

    Best of luck,

  39. Phil Patelmo says :

    We are looking into buying a beautiful house in Hilltown, Pa however there are power lines, the big towers in the back yard about 500 feet away from the house. The look doesnt bother use its the health concerns since we have 2 young kids, 10 and 12. Should we avoid this house? How can I find out if the house and yard are too close and if its dangerous?



  40. Jeffrey Sand says :

    Look into Advanced Tachyon Technologies products!

  41. Alex Stadtner says :

    Assuming you’re talking about magnetic fields – it’s probably an electrical wire or other piece of metal carrying stray current (e.g., water pipe, gas line, data wire).
    You could turn off circuits one at a time to determine a) if the load creating the magnetic field is within your home, and b) what circuits affect the magnetic field strength.
    Good luck and happy new year,

  42. Scott Blais says :

    I have a high reading near a wall thats nowhere near any appliance or breaker box etc. What would cause that? Nowhere else in whole house do I have it. This is a wall right up against outside only thing near it is an outside electrical outlet on house, again nothing plugged in. Thanks for thoughts in advance

  43. Alex Stadtner says :

    Check your meter and make sure you’re reading along the right line. Since the Tri-Field claims to measure electric, magnetic, and RF radiation… there are 3 different lines/units you should pay attention to.
    That meter is notoriously inaccurate, so us it like a “detector” more than a meter. If it goes up in a certain area – pay attention. But don’t get too hung up on the numbers themselves.

  44. Bernadette says :

    I could use some help understanding the readings in my master bedroom. It’s located above the room where the electrical/fuse box is located, cables come into the home and smart meter is outside.
    Reading using the TriField Meter on Magnetic (0-100 range) are over 100 milligauss on that specific wall. The bedroom readings range from 12 up to 70 using the same meter setting.
    Leaving the room readings instantly drop. Other rooms all in mostly safe ranges or well below except the room that is below the master bedroom. (which is where all the culprits are located)

    I have chronic illness and know this is impacting my health. I’d like to figure out if I am reading this correctly and then how to “shield” my room or at least the sleeping area. There is no other room to move to.

  45. Alex Stadtner says :


    I’m sorry the cell tower is giving you such concern.

    From a cell tower, most folks would be primarily concerned with radio frequency (RF) radiation.

    1) The answer to which meter – depends entirely on budget. Get the best one you can afford. Safe Living Technologies and LessEMF both sell the Gigahertz Solutions RF meter. The higher-end Gigahertz meters with the omni-directional antenna are a good place to start. You’d need two in order to cover up to 10 Ghz. So it’s pricey. A less expensive option might be the Accoustimeter. And if you’ve got budget than consider a NARDA for professional measurements.

    2) There are many different ways to shield your building from RF. The easiest and quickest method might be to hang RF shielding canopies over your sleeping area. Hard to comment beyond this without evaluating the space. With the meter you may learn that the RF isn’t that bad, or that your walls are shielding the RF but the windows aren’t, or visaversa, and all these clues would influence an effective RF mitigation plan. Don’t do any RF abatement before you have a meter to verify you’re actually lowering levels of RF. It’s possible you make things worse with some shielding strategies.

    Find a local Building Biologist to assist you in this effort.

    Best of luck,

  46. adelita says :

    hi Alex,
    I live in Indonesia. my house is one storey. and the BTS cellphone tower is within 10 meters of where we’re living. i am so concerned of the radiation (EMF.ELF.and RF) this tower emits that can harm human bodies. Sadly the safety surveys that has been conducted so far are all funded by this telecomunication companies providers. so i am really doubting the result. all are saying the EMF result goes around 0.55W/m2 which is far below dangerous. However i am not satisfied with this answer and i would like to find the truth.
    1. what meters would be best and easy to use for a starter like me? ive been having a hard time finding this meter here that can measure both three EMF.ELF.and RF. i might have to order via
    2. what can i do to shield our family from this radiation exposure (if its proven theyre beyond safety level)?
    best regards

  47. Jonathon Tate says :

    Great article as always. Very informative. I have used a couple meters (not detector) from a company called aaronia USA for site surveys at my own home and clients’ homes with great success. The price was in the low thousands, so this may not be a consumer-grade piece of equipment, but as far as frequency accuracy and signal strength, this is definitely one of the better tools I’ve used. I know their rf analyser kits come with a directional antenna – the salesman I spoke with there suggested this specifically for interference hunting (another aspect of the site surveying I do). I’ve got one of their kits that comes with the rf analyser, low frequency analyser, and the antenna all togehter- i think this one

  48. Sophia says :

    Hello RC,

    Please check out our EMF blog on accepted limits and EMF conversions.

    Whether it’s “safe” or not is a question we’re not able to answer. But I suggest you read the BioInitiative Report and draw your own conclusions about EMF Health Effects.

    Lastly, when most people discuss the dangers of “smart meters” the last thing they discuss is magnetic fields. Most folks are more worried about the Radio Frequency (RF) radiation emitted from the meters to relay data back to the utility company, and the high-voltage transients (aka: “dirty electricity”) that the electronics in the meter will put on the electrical system of the building. These are measured with different meters, quantified in different units, and mitigated in different ways than low-frequency magnetic fields.

    Best of luck with your EMF inspections. Doing it yourself is a long slog unless you’re electrical engineer, physicist, or Building Biologist with lots of training and equipment.


  49. RC says :

    Took a “magnetic field radiation” reading on my “smart meter” today using the Benetech modle GM3120 and at its highest reading came back 19.71 μT. The meter says this is a dangerous level. Is that true? I’ve not been able to find a chart showing magnetic field radiation levels based on μT readings; they all seem to be mHz and gHz.

    Thanks for your help.

  50. Sophia says :

    Yes. If you’re serious about collecting data on impacts from the upcoming cell tower – getting a “before” measurement is a key piece of information.
    Call the San Francisco or San Rafael office, or find another local EMF expert to perform an independent, 3rd-party EMF assessment.
    Best of luck,

  51. Sophia says :

    Radio Frequency (RF) radiation can be blocked or shielded by any number of metal-containing fabrics, foils, screens and paints.
    We suggest you first hire and EMF inspector to identify the primary offending external source and collect pre-mitigation measurements.
    It’s possible that DIY EMF shielding may lead to more harm than good, so we suggest having and EMF expert onboard during design, installation, and ultimately present to verify that the target reductions were achieved.
    You can buy all sorts of shielding materials from folks like Safe Living Technologies and LessEMF.
    After a site visit an expert with the right meters can tell you what materials would be most effective in your particular situation.
    Best of luck shielding your building from the exterior radiation.

  52. Assem says :

    The council has approved the installation of a 30 metre telecommunication tower. Is it possible the EMF radiation outside my house before and after the project?

  53. syed mahmud says :

    may I know how can I reduce the telecom tower radiation for any nearest building? what will be the materials for reduce radiation for a building ?

    Thank you
    Ar. Syed

  54. Alex Stadtner says :

    Many Building Biologists believe in or use (and even sell) BIOMATs. I have tested them and found significant DC magnetic fields on the matts.
    We have not done extensive testing or research on the mats. Personally, I continue to practice the underlying principle of Building Biology – getting as close as reasonable/possible to nature.
    In general building biologists advocate avoiding anomalies in DC magnetic fields – so I don’t know why so many are comfortable using the BIOMAT.
    THanks for reading,

  55. Q&A-California says :

    Hello Alex,
    Can you tell me anything about EMF danger with a product that has many different manufacturers called BIOMAT.
    The far infrared heat is supposed to be very healing for a bodily injury I sustained, but I am concerned about bodily damages of lying on this electric mat from any EMF.
    Wow this dialog is eye opening regarding EMF and HBS

  56. […] driving that day and it occurred to me that it would allow an excellent example of syncing a Gaussmeter with GPS path tracking to be […]

  57. Alex Stadtner says :

    The least expensive and best approach is to hire and EMF expert.
    Short of that you can purchase 4 meters: low frequency electric fields, low frequency magnetic fields, dirty electricity and radio frequency (RF) radiation.
    Buy at least mid-grade meters or they’re worthless and will only confuse the situation.
    Then you’ll have to learn how to use the meters. Most are easy on/off, but some you have to toggle between different frequencies and can read in different units.
    Then try and understand the units and “how high is my EMF.”
    Then try and understand why any “hot spots” are present in the apartment.
    Lastly, try to eliminate the source (first goal) or shield/filter against any source of EMF you think is too high.
    Unless you’re a physics major or a real DIY/research-type, you’re better off hiring an expert to perform and EMF inspection.

  58. Alex Stadtner says :

    As with most such cases – we’d advise a two pronged approach.
    First you should speak with a medical professional about your symptoms.
    Second you should probably have an EMF expert survey the apartment.
    There may be something unusual occurring in the floor.
    If several people who are otherwise not sensitive can “feel the EMF,” than it’s worth checking out for sure.
    You could buy many meters and try and figure it out yourself. Get the best meters you can afford.
    Then you’ll have to do a lot of research to try and understand what the measurements mean.
    And lastly you’ll have to do more research to try and understand what is causing any anomalies and how to address each one.
    If you’re a DIY guy and researcher – go for it. If you just want help in the most affordable and expeditious way possible – hire an EMF expert.
    Best of luck.

  59. Alex Stadtner says :

    Radio Frequency (RF) radiation is measurable and can be shielded rather easily. You can get an EMF inspection or try and buy meters and figure it out yourself.
    You can hire an EMF mitigation expert or try and figure it out yourself. Aluminum foil or fine mesh metal window screens are the less expensive ways to shield RF.
    Although we always advise caution when installing EMF shielding without the help of an expert – you can make things worse. And the foil is a vapor barrier so you must consider other building science variables… such as moisture flow and accumulation.
    Best of luck.

  60. Sam says :

    Hi, I’ve been living at my address for 3-4 years now. My apartment is situated within the center of the building. For at least a year Ive been feeling strong electricity within my apartment but I thought i had been misinterpreting it. More recently 2 unconnected people have both said to me they can really feel the electricity in here. If it’s just started within the last year & i haven’t changed anything within my I’m quite certain the source of the problem is not coming from my apartment & is most likely coming from elsewhere. It is now so uncomfortable where I live it’s keeping me from sleeping & making me feel sick. Any advice on how to begin a proper investigation on this issue would be greatly appreciated.

  61. Sam says :

    Hi Alex & Hi all, I’m glad I’ve found this page. For at least a year now i have felt what seems to be strong electrics within my apartment, I decided not to do anything about it because I thought i was misinterpreting what i was feeling but then 2 different people unconnected to each other both have said in the last 6 months they can really feel the electric in my apartment. I hadn’t mentioned to either of them anything about me feeling electrics. One of the people said it hurts their feet which is exactly what it’s been doing to me for some time now, i also experience pain in my legs. Most nights i can’t sleep & if i do get to sleep i wake up sometimes seeing stars & feeling like there is a strong electric current running through my body. It would make sense that where i live would be affected so much as i live in the center of a large apartment building. At the moment I’m trying to spend as much time away from my apartment as it’s just got to be too much for me. I will have to have a good read of all the posts here, after 2 weeks of researching what to do, it seems the first things is to measure & or detect the source of EMF (?), though I’m not sure what i can do after that other than to move ? Thank you.

  62. Matthew says :

    When dealing with gov microwave & electromagnetic weapons and freqs that can go thru any thing including the human body how do you protect yourself from such strong fields. Its like you are a target which involves satellites and other equipment. How would you detect where and how strong the signal is im trying to build a case against the gov. What would you do in my case when you feel like you are a target of these two things which is very harmful im already battling cancer from the radiation i can feel the electromagnetic energy moving thru my sofa when im sitting there. Im sure you have heard of this being done by our own gov. These two energys can cause heart attacks strokes and cancer. If you dont believe me look it up its called gov electromagnetic attacks on targeted americans. What is the best way to block or protect yourself from powerful magnetic enegy and to keep it from entering your body i deal with this every nite for the past 7 years no matter where i move. Will you please help me by telling me how to protect myself . I have also had chest pains from the electromagnetic & microwave energy or attacks. I will be waiting for some good advice, please help if you will or can . Thank you

  63. Alex Stadtner says :

    I’m afraid that’s too little information to go on. Measuring EMF is a broad topic and requires many different types of meters.
    Are you measuring electric fields, magnetic fields or Radio Frequency radiation?
    Alternating Current (AC) or Direct Current (DC).
    What is the unit?

  64. dan says :

    if i get a reading of just a number 1 on the far left corner of the meter what does that mean?

  65. Alex Stadtner says :

    Sorry to hear about your health troubles and EMF worries. Sounds like a difficult situation.
    Proving that the external sources of EMF actually caused cancer will be next to impossible, but there are lawyers who would take such a case.
    Search Google for some “EMF Lawyer” or “EMF legal support” and you’ll see the organizations making their stands in courtrooms.
    Either way you’d need a professional EMF survey to document the levels where you sleep and how the levels compare with and without any influence from your own building.
    Often times think that outside sources will be the most significant source of EMF… only to learn that they have internal household sources that are more significant.
    You’ll need an independent expert to come in with good equipment and write up a nice EMF report.
    Best of luck,

  66. ava says :

    Hi,, I live within a triangle of electric transformers. My small home is within that triangle and my bed and head are underneath the power lines. Up to the time that I moved in this house I was in perfect health and there was only one transformer across the street on the pole. A new development made the electric company place tree more poles and transformers increasing the electricity passing above my head. I can document the intervals of their placement with my constant hospitalizations with cardiac issues. My heart’s electrical system is damaged, and I suffer from arythmias, palpatations, irregular heartbeats….etc… I was recently diagnosed with a brain tumor and a tumor on my neck. How can I prove either way if these ailments were caused by the emfs?? Can’t find a lawyer so how about for the rest of the people that may have the same problem. thank you…not many people know about ems.

  67. Alex Stadtner says :

    You can find a qualified Building Biologist here:

    And you might just try calling Matt at Healthy Dwellings:

  68. Greg says :

    I am looking to potentially purchase a home that is approximately 1200 feet from some high voltage transmission lines. Suburbs of New York City. Given the proximity, I wanted to get a professional EMF / EMR assessment of the property. Do you know of any service providers in New York area / Westchester? Does that proximity raise a red flag to you? Thanks – have two children and trying to be thorough.

  69. Alex Stadtner says :

    In general TV and radio signals are considered less biologically active, and therefore less of a concern. But often cellular antennas are attached to radio towers and these are constantly sending pulsed data packets using radio frequency (RF) radiation at relatively high power density. If you can see the antenna – clear line of sight without any obstructions – than the RF will probably be elevated in this particular condo. Picking a condo even on the other side of the building… where the rest of the building acts as a shield between you and the antenna… would make a difference. Lastly, if you do get the place there are ways to shield for RF within the unit. But it can be costly and will take time.
    Hope this is helpful,

  70. Robert says :

    Hi Alex,
    We are thinking about purchasing a condo
    It is located on the 11th floor of a building (total 17 floors) that is located not quite
    2/10 of a mile away from a tv/radio tower
    Do you think this could be a concern for health issues
    Will a gauss meter measure the waves
    Also, what type of inspector would we hire, if we want it tested and what type of test should we request

    Thanks so very much

  71. Alex Stadtner says :

    You may or may not have a significant EMF exposure issue.
    In order to check you’d need a magnetic field meter, electric field meter, dirty electricity meter, and radio frequency (RF) meter.
    Or you could hire a building biologists to perform a professional EMF inspection.
    Best of luck,

  72. Al says :

    Hello Pawel! Could you please share more info on “The easiest method I know is to use loop with several wings connected to music card in laptop and use application “osciloscope with FFT”. Many thanks!

  73. Doug says :

    I live in an apartment building. On the back of my bedroom wall there is 12 electric meters. The wall is brick. Should I just move or get a meter and test what’s coming thru that wall. If the EMF is going to be high, I would rather move.


  74. Alex Stadtner says :

    The easiest method I know of is to use an off-the-shelf spectrum analyzer.

  75. Pawel B says :

    Comment for spectrum analize of low frequency – haw to check frequency?
    The easiest method I know is to use loop with several wings connected to music card in laptop and use application “osciloscope with FFT”

  76. Alex Stadtner says :

    Hello Cheri,
    What units of “EMF” are you measuring in? Are you measuring electric fields, magnetic fields, or radio frequency radiation?

  77. Cheri says :

    Can someone please help me understand ….my quick summary and medical background…

    I’m 28 female and
    I’m extremely sensitive to wifi…blue tooth… My cell phone. …..I get an instant red rash wherever any cell phone is being used within a certain distance of my body. I develop brain fog and struggle with concentration and cognitive functions. Ex. hardly find the words I wish to say when I hold my phone or iPad to close while typing or forget my initial point which I have previously thought prior to grabbing device for communication. I have bad heated skin “fried skin syndrome” mottled skin in my thighs when using electronics which seem to be blood circulatory related. (Go away when legs elevated)….um, I can no longer wear jewelry without my veins bulging and skin turning pale. My eyes develop a dark red brown tint on my eye lids if I’m exposed to any wifi/Bluetooth/cell phone. as mentioned my “red rash” only develops on my face and arms from cell phone use…..

    ?.I haven’t any luck with medical professionals here in Calgary ab. I am told by doctors it is not their field of study. People seem to disregard or think I’m crazy when I state my symptoms and physical reactions. One Example is I would say the closer I move my hand to any light fixture instantaneously my veins in my hand bulge and it travels from my hand to my wrist, arms, shoulders and chest depending on duration exposed. I have had bruising develop from two minute durations of testing having my hand placed 5 inches from our bathroom light that did not heal for at least a week or two……

    So…. I purchased an electromagnetic radiation detector;

    When I measure electronagnetic radiation from devices I am having readings no greater than 30-500 on average..when I hold the device up to myself and my joints such as wrist, knees, thighs, stomach – I read now anywhere from 500- and mostly 1600 plus with the highest points being read at 1945. I don’t test often, sometimes a few months I will and my reading is literally gradually being increased. No other human being I know whom I have tested has read more then 1100 (being the highest in their wrist) and everyone else on average usually reading at 0.30-500 max.

    Can anyone please assist me with what this means? Why am I so sensitive. What does my readings mean if they are causing my electromagnetic radiation detector to beep like crazy and gradually increase to now 1900+



    I’m 28/f and from Calgary AB Canada
    [email protected]

    Thank you

    Cheri Interman

  78. Alex Stadtner says :

    Hello Al,
    We have done some basic EMF testing of cars. We’ve tested several models of Toyota Prius and a couple Tesla models.
    Results have varied dramatically. Some we have successfully mitigated magnetic fields with shielding material, others were too high to successfully mitigate.
    Good luck,

  79. AL says :

    Hello Alex,
    First of all I want to thank you for this blog.
    I bought a new car 1 month ago. It started building cabin pressure and I felt pain in my ears in 5 or 10 minutes driving in the car. I blamed the road noise but it did the same even with the car idling in a drive way. I, also, felt pressure and ear pain just sitting in the car with the engine off. I started reading what the causes of that situation might be and the Electromagnetic field radiation was coming up when I wrote about symptoms. I went to the dealership telling them about the issue and mentioning electromagnetic radiation as one of the possible factors causing the ear pain. The answer was “We have never heard of such a thing before”. I insisted and finally they decided to start checking the car. Yesterday, they checked the ventilation and ruled out any problems with vents being blocked.
    They told me that they will contact their engineering department for further instructions.
    I, also, drove another brand new car exactly the same trim level and I did not experience any problem.
    I would appreciate very much if you have any experience with electromagnetic field radiation in the cars and what would be the solution.
    Thank you,

  80. Alex Stadtner says :

    You might consider having an expert assess your property for EMF. You may have other electric or magnetic field issues, or problems with neighborhood radio frequency RF radiation.
    There are some great Building Biologists in Florida.
    Best of luck,

  81. sue newman says :

    thanks for your great help.
    i have m.c.s. i awake at night and morning,my body is ‘buzzing’ or vibrating. it’s not my heart. it takes several minutes for my own
    body’s field to take back over. and i awake exhausted. i have slept all over the house and it’s the same. i have turned off all breakers
    except the fridge. still the same. lately the phone sometimes screams at incoming callers. (like a fax connection) or sounds ‘busy’ to
    callers when i am not on the phone. house measures .3 to .4. with elf , f.w. bell, model 4070. my tin-roofed wood back room feels tingly all
    the time.
    my floors are terazzo, .a block 50’s house with rebar underneath. i am close to the ocean in florida. my house was ‘floating’ when i bought it 14 yrs ago. they put down
    3, 8 foot rods and in a triangle to ground the panel. what is my next step? thank you so much for the work you do.

  82. Alex Stadtner says :

    We’re not aware of this product that reduces dirty electricity and reduces energy consumption. Most of the high voltage transient conditioning devices (aka: “dirty electricity filters”) require a little current (amperage) and therefore would slightly increase a building’s energy demand. Share a link or your experience. We’re always learning more from readers like you.

  83. atoy says :

    Hi Alex,

    May I know if by blocking or rechanneling this EMF, will it reduce our power consumption. There is a product in the market now that claim to reduce the power usage by up to 25% by blocking this emf. It is a sort of card to be pasted on the breaker or on the main wire leading to the breaker..

  84. Alex Stadtner says :


    Wow. That’s really dry. <40% relative humidity is a problem that would warrant using a humidifier. Make sure you clean out the reservoirs and condensing coils of your humidifier to avoid mold growth and “humidifier lung.”

    From an EMF standpoint most plug-in devices produce two forms of low-frequency electromagnetic fields (EMF): electric fields and magnetic fields

    You would have to unplug the units in order to eliminate electric fields. E-fields will still be present even when the device is turned off.

    But most “EMF meters” measure magnetic fields. Mag-fields require current (amperage) so they are only present when the device is operating.

    Hope this answers your question.

    Best of luck,
    Healthy Building Science

  85. Dirk says :

    Hi there,

    After reading your page, I am interested in the following:

    Do EMF;s completely disappear once the machine is unplugged?

    The background is as folllows: I have bought multiple EMF meters. And while using them, I identified my two electric humidifier seems to be “bad guy” due extremely high mGauss reading (higher than my EMF meter could measure). :s

    I would still prefer to use two machines, because they are easy to operate and in the winter here (Holland), the humidity gets around 28%. Non-electric humidifiers in the past I tried, but non were to my liking.

    if I use these two humidifiers while I am not in the room, am when I get back and unplug these devices is this a safe option? Or can these EMF’s linger?

    Thanks for the advice!

  86. Alex Stadtner says :

    Do a search for a “spectrum analyzer.” That’s what you need. Or there are some RF meters where you can install attenuators that “choke out” all frequencies except a given bandwidth. Bottom line is you’re going to spend a pretty penny being able to ID and measure higher frequency radiation at different frequencies. For lower frequency electric fields and magnetic fields, there are meters that can easily break down the field strength or magnetic flux at different frequencies. The NFA 1000, from GigaHertz Solutions, is a great meter that quickly illustrates several key bandwidths and can tell you whether the predominant band is 60 Hz (US) or a higher frequency harmonic (e.g., “dirty electricity.”
    Good luck!

  87. Glen Gauld says :


    I’m currently conducting some research into electromagnetic radiation and I was wondering if anyone might be able to help me with some information. I’m looking for a device that can tell me what frequency the radiation of a device is currently at (wirelessly), the problem is it needs to be able to show me extremely low frequencies (ELF, 0Hz and up). Is there any device that you know of that could help me with this?

    Thank you very much for your time
    Glen Gauld

  88. Alex Stadtner says :

    I’m afraid not. You should probably search for the EMF meter name/number online.
    If your emf meter is from a reputable source like Safe Living Technologies or Less EMF, they should be able to get you a manual via email. Healthy Building Science does not sell EMF meters or maintain a database of user manuals.
    Best of luck,

  89. mohsen says :

    hi every body
    I buy a EMF field tester but it has not manual to use it,so I can not find about it. if u hv manual about this instrument or similar, plz send to my gmail.
    thank you

  90. Alex Stadtner says :

    Thank you, Harold.
    Like the fact that smoking causes cancer or humans have caused climate change, for some the truth is hard to swallow.
    There remains much we do not know about how EMF impacts living organisms, but what we do know should no longer be questioned or ridiculed.
    While now a little outdated I still refer people interested in EMF health effects to the BioInitiative Report.

  91. Harold Rosenberg says :

    Sorry, I forgot to put the link to, “The Calcium Rationale in Aging and Alzheimer’s Disease”.

  92. Harold Rosenberg says :

    To ALL THE PEOPLE , who say that emf/emr does not affect us, unless it heats the tissue, need to read two papers by Dr. Martin Pall, “Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects (” and “Microwave electromagnetic fields act by activating voltage-gated calcium channels: why the current international safety standards do not predict biological hazard (” Emf/emr causes us health issues because it opens up the voltage-gated calcium channels enabling calcium to flow into the cell. This puts excess calcium into our cells and excess calcium in our cells is NOT good. The paper, “The Calcium Rationale in Aging and Alzheimer’s Disease” gives a good overview of the importance of the timing and the right amount of calcium.

  93. tony says :

    Hello, I need your expert opinion. It’s my understanding that if anyone feels that there is a leak of some sort of EMF or waves, they need to be reported to health department? If so, The address listed above, I’ve been experiencing all kinds of severe head aches and other symptoms. I decided to download couple of readers in my cell phone. Both have read a high EMF during specific times in the day and night. Do you know where I can turn this information that can help me get a inspector out?

    Tony 310-721-5686

  94. Alex Stadtner says :

    There is actually considerable evidence that EMF does cause harm.
    Review the summary pages of the BioInitiative Report. They cite peer-reviewed, published studies that indicate humans do suffer ill health effects from EMF and RF exposure.
    The real question is at what levels and what duration of exposure are we at risk. According to some studies we should be quite concerned.

  95. Michal says :

    There is no reliable research that would prove EMF from electric grid harmful. On the other hand there is no such to prove the opposite either.
    I’ve heard of experiment (or was it just an observation), that a deer rather crosses a highway with intensive traffic than to walk under high voltage line (400kV). This means something, but it’s still not a proof.

    It is amazing that you live 15m from 25kV railway grid. 25kV in rail is designed for high speed trains (above 200 km/h) which in turn are rather isolated from habitats (like freeways more or less). Are you sure it’s 25kV AC?
    It is relatively low voltage, but such a small distance… I don’t know. Regular 50Hz is not an issue, but you’ve got a whole spectrum of frequencies (harmonic distortions) caused by rectifiers and engines of trains and substations. This is what you hear in your amp.

    What is the voltage of this electric grid? If it’s less than 110kV, then I wouldn’t worry. Both magnetic and electric field decreases exponentially with distance. Do you hear a characteristic crackling noise emitted by the line? High voltage lines sometimes do crackle, especially while high humidity. In such cases you can see a blue light around the line if the night is dark. It’s called partial discharge. This would tell you it’s definitely at least 110kV.
    If your house has steel reinforcement bars, then it’s a sufficient protection from 60Hz field (check Faraday’s cage on Wiki).
    Thus if you use a wi-fi at home (or your neighbors do and you detect it with your laptop), or if you catch signal with your cell – then you live in EMF world and 60Hz radiation is no longer a concern. We’ve got several GHz radiation all over us.
    Even when you turn on your vacuum cleaner you get a nice dose of EMF, which is nothing to compare with what you get from your cell while talking (remember, distance is a key). Solar panels (or actually their power inverters) do the harm as well.
    This electric grid outside your window may look sinister, but it’s much less dangerous than what we have at home.

    Glass is not opaque to infrared, it is opaque to ultra violet. That’s why when you stand by the window, you can feel the warmth of the sun (IR), but you can’t get tanned (blocked UV). It’s also opaque to frequencies higher than UV I think, like X-ray. However this article is very nice, it shows that we produce all this junky EMF around us.

  96. Alex Stadtner says :

    Hello Chris,

    Sorry to hear of your troubles. It seems common that when folks with multiple chemical sensitivity (MCS) are exposed to high electromagnetic radiation (EMR) that they are sensitized to EMR and become electrically hypersensitive (EHS). If you believe in the overflowing barrel analogy (“total load” or “body burden”) of health symptoms, this correlation isn’t too surprising.

    In general Bau Biologists, or “Buildings Biologists,” are the best equipped to measure and mitigate EMR in the US. However, like hiring a “Doctor,” not all bring the same experience or equipment to your bedside. While I’m hesitant to point the finger at any Certified Building Biology Environmental Consultant, a different set of experience and instrumentation may lead to a different conclusion about your office.

    It is possible that the walls/windows of your new office are shielding the RF, or that you’re in the “shadow” of the cellular antennas’ range. It is also possible that this EMF consultant’s meter didn’t capture the higher frequency RF… or that it’s electric fields, magnetic fields, or high-voltage transients (“dirty electricity”) contributing to your new symptoms.

    Sorry I don’t know anyone in your area with our set of expertise or equipment. We travel across the US and would be happy to assist. Fill out our Get A Quote Form if you’d like to know how much a comprehensive EMF survey would cost.


  97. Chris says :

    I recently purchased an office, which i didn’t realize at the time, is within a few hundred feet of 2 high rises, both of which have cell phone antennae on top. I am in a 2 story town house structure. Since moving in, I have had headaches every day.

    I am chemically sensitive so was very aware of building materials and such – and is definitely not the issue – the place is chemically pristine. I had never had an issue with EMF before, but was aware of the possibility.

    I had a new graduate of the Bau Biologie program come to assess the place. He said there was nothing detectable from the cell antennae and very little else within the building other than my wireless router and cordless phone (both of which I have replaced, with no effect at all on my symptoms). The idea of there being no RF from the cell antennae seemed highly unlikely to me – there are dozens of these things on top of the building, many within direct eyesight, less than a few hundred feet away.

    I read somewhere that some cell antennae emit RF in 10-20 GHz or higher – a range which the Bau Biologie assessor said is beyond his equipment (which measures up to about 4GHz).

    Do you know anyone either in or willing to travel to the Wash DC area to do further assessment? Or do you have any other ideas?

    Thank you for your work.

  98. lisa says :

    i have used EMF and ELF meters that I own in the past to located ‘wireless’, ‘cell’ and ‘power line’ range values for properties we have lived at or considered living at.

    we are not looking at a home that is located 0.5 miles from a RADIO antenna — one that has at least dozens of various antennas for communication, primarily it looks to me for businesses, sheriff, fire department, etc. (it is the top of a mountain)

    i used my “EMF” meter and found very low levels of (12 uw/m2) but i know i must be missing the ‘radio’ frequency bands (there might be an FM station transmitting from up there, too).

    how would i measure those please? i have a cornet electrosmog meter that i purchased because it went up to 8 GHZ — would that be sufficient? most of the antennas are in the 150 MHZ range, but some are 900 MHZ…

  99. Christina says :

    I am looking to buy a flat in a block of flats and as it is a former brownfield site there are electricity pylons in about 200m proximity to the block. The overhead cable itself runs about 30=50m left near the side of the property. I am, very worried of radiation and potential health risks this may cause. Is there a way to measure if the EMF is safe or is there a professional firm that conduct this service ?
    I have cancer running in my family and worried of this potential exposure. Any advice would be much appreciated.

  100. Gerard says :

    Hi there

    I have 25000V railway lines running about 15m away from my bedroom window. I don’t intend living in this place forever but…… how much of a concern is this? Certainly the wires are emitting enough electromagnetic noise to cause a hum through my guitar amp. Cheers 🙂

  101. Cameron says :

    Hello there, Dorab27!

    It is very difficult in the modern house to have all the appliances completely off. There are still ‘vampire’ loads from power transformers, LED displays, Comcast boxes, etc. all slowly drawing electrical current, which cumulatively adds up to more than you would expect. Plus, many appliances have cyclic power draws so they might be intermittently off, but will come on for 5-15 minutes every couple hours (i.e.: refrigerator compressors, HVAC units, etc.)

    The EMF problem with electrical panels is the magnetic fields that they generate. These can be minimized by using very energy efficient devices/lighting, and minimizing the number of devices/appliances as well. Further reduction can be achieved by rewiring the panel in a low-magnetic field way or even shielding the panel, as you suggest. The problem with MF shielding is that, unlike RF shielding, it is not very effective. One of the best materials on the market will only reduce the MF by about 25%, sadly.

    Distance from the panel is the best attenuator of magnetic fields. Typically we recommend at least 5 feet. For a child’s crib, I am more likely to say 8 feet. It is the general thought of the medical community that children’s bodies are more susceptible to exposure issues since their cells are more rapidly dividing than that of an adult. The World Health Organization (WHO) has listed long term magnetic field exposure in excess of 4.0 mG as being a Class 2B Possible Human Carcinogen. WHO sees a statistical correlation with increase in risk of Childhood Leukemia, however they do not understand the vector as yet (and so call it ‘possible’).

    The area near the Washer-Dryer is liable to be of much lower magnetic fields (barring a N-G electrical fault inside the Washer-Dryer). Also, to help with your RF exposure from the WiFi router: if you use a NetGear WiFI router there is a hardware On/Off toggle switch for the WiFi connection on the front of the router. Rather than just turning off the WiFi at night, I leave my WiFi connection Off, but do turn it On when I need it and then turn it Off afterward. The great thing about the NetGear Wifi routers is that turning Off the WiFi does not turn off the Ethernet networking ports at the back of the device. I have all my personal computing components connected via Ethernet, and if I should choose to use my laptop on the deck, I turn on the WiFi only for that time. In this way, you can minimize your RF radiation exposure as Ethernet will allow you to network without a significant RF radiation exposure.

    So, my recommendation is to move the crib and use the WiFi only when you need it (maybe invest in a NetGear router to make it easier), rather than just turning it off at night.

  102. Dorab27 says :

    Hi, we just moved to a large apartment building (20 floors) and our baby’s crib is positioned 4 feet away from the electrical panel. Does the panel emit EMF even when no appliances are in use? If so, is there something we could cover it with, or it’s just not enough? What’s the minimum distance the crib should be away from the panel?

    The alternative would be to move the crib but it’d mean it’d be closer to the wifi router on the other wall and also to the washer-dryer. We switch off the router at night, and the washer dryer is also off, but do they still emit EMF in off mode?

    Thank you very much for your insights and any suggestions!

  103. Alex Stadtner says :

    Yes. The TriField is not particularly sensitive to low-levels of electric and magnetic fields.
    You might try with a more sophisticated meter, or consider bringing in a Building Biologist for a more formal EMF Survey if you’re serious about getting to the bottom of things.

  104. Alex Stadtner says :

    Hello Maria,

    Thanks for writing in about how to measure EMFs and how to interpret the readings.

    Firstly I must say that the adage – “you get what you pay for” – is especially true when buying meters. The TriField meters are okay at detecting (not measuring) higher point sources of EMF/EMR, but not so good at detecting low levels of radio frequency radiation, or electric fields or magnetic fields. So I wouldn’t entirely trust your meter if you’re using the Building Biology EMF thresholds for sleeping areas.

    Whether or not EMF/EMR can travel through a wall depends on what form of energy [low-frequency electric or magnetic, or radio frequency (RF) radiation] is present, and the materials in the wall assembly. So I’m afraid without knowing more details of your case I cannot give an accurate answer.

    Best of luck, and I’m glad you’re investigating this stuff!

  105. Maria says :

    I forgot to mention in my question ———

    there is nothing electrical in the piano and the LED lights are not very close to it—

    When we tested it I could not tell with the tri filed meter when they were on or off. best

  106. Maria says :

    I have read that metal reflects radiation, creating unknown hotspots. —–( Metal window frames, chairs, tables, beds, and filing cabinets are all possible contributors —they say )

    This kind of radiation reflected by metal can go through the walls?

    For example my next neighbor has a little piano * steal skeleton and metal chords inside) on the adjacent wall of my bedroom where my bed is . He also has LED lights tape on that wall. I cannot detect anything signifiant with a tri field meter

    May I assume that it is OK?

    Many thanks

  107. Alex Stadtner says :

    In general we would not suggest that anyone – especially a child – places their head next to an electrical meter for extended periods of time. While I’m not a doctor and don’t give medical advice, I would not panic or worry about long-term effects. Instead I would try to reorganize the room in such a way as to maximize the distance between your child’s head and the electrical panel. That is the path of least resistance. There are more advanced and costly measures you could pursue to reduce the impact of that meter on the occupied portion of the room. These other techniques would require an electrician to do some wiring diagnostics and clean up the panel, and also a handyman or contractor who could help install dirty electricity filters (presume it’s a smart meter) and some magnetic field shielding material.
    Best of luck,

  108. Shirley Francis says :

    Hi, as the bedroom is so small, my grandsons bed is right next to the electricity meter, so that his head is close to the Meyer door. Is there anything to be worried about concerning electro magnetic fields? Thanks.

  109. Ellen says :

    Hi Alex,
    I am looking to purchase a propertysituated within 40ft of a pole, I can only assume is cable/telephone. Can you recommend a good meter to purchase so I can measure the EMF levels and whether this poses health risk? I have a 4yr old so want to be vigilant. What reading is deemed acceptable and over what level should I be concerned?

  110. Alex Stadtner says :

    Low frequency electric fields and magnetic fields (EMF) can be detected from wiring embedded in a wall, floor, or ceiling cavity.

  111. syafirul says :

    Can emf detected embedded wire in the wall

  112. Stephen says :

    We live in British Columbia, Canada in an apartment bldg. On the opposite side of our bedroom wall 35 smart meters are installed on a metal structure and 35 more at two stores above. Should we be concerned? The power company says all meters send the data to one meter and only that meter sends wireless data at a lower frequency than a cell phone at a radius of a few inches. I have a cheap detector which reacts to a wireless phone base 1-2 feet away, but does not sound when placed along our bedroom subject wall. No one is willing to do a proper measurement (unless we pay around $5,000). Your advice would really be appreciated.

  113. Alex Stadtner says :

    Hello Samantha,
    For a regional Building Biologist you could trust the work of a Building Biologist doing EMF Surveys in Chicago = She could perform an EMF survey / inspection of your place in Chicago. Her business is called Indoor Environmental Diagnostics, and she’s located in Carol Stream, IL. For some rules of thumb about EMF you might read this other blog from Healthy Building Science. There are some crude rules about proximity to power lines and transformers. But even these are crude. It would take someone with a meter to tell you how these lines affect your home. And magnetic fields can fluctuate seasonally and daily depending on the neighborhood electrical demand / load.
    Best of luck,

  114. samantha says :

    Hello, I am hoping someone can help answer my question. We recently purchased a new construction home close to telephone wires and a three barrel transformer. Our bedroom is right next to the polls and so is the guest bedroom. I have been trying to find someone to come and get an EMF reading but have been unsuccessful as we live in Chicago. Do you have any ideas on the amount of EMF power lines and transformers emit? Any answer would be greatly appreciated.

    Thank you

  115. Alex Stadtner says :

    Hi John,

    Thanks for writing in. There are two questions wrapped up here:

    1) Is there unusually high levels of EMF where I work? This would require an assessment with numerous meters to evaluate electric fields, magnetic fields, high-voltage transients, and radio frequency radiation. As a general guideline I would suspect that there is a significant amount of power and transformers located around the IT hub for a university, but without field measurements we’re really only hypothesising. From a precautiounary standpoint, you’re wise to ask and it may behove you to investigate further with via an EMF Survey. You can find a local certified Building Biology Environmental Consultant via

    2) Are these levels of EMF dangerous? This is a purely medical and epidemiological question that we must shy away from. However, if you’re looking for a compilation of peer-reviewed studies that have been published and indicate cause for concern, you should check out the BioInitiative Report. In their appendix and throughout the document they propose precautionary exposure limits… not unlike those adopted by Building Biologists and the Austrian Medical Association.

    Let us know if we can be of further assistance.


  116. John says :

    I work underneath our university IT department… Many servers whirring constantly above me… Is the dangerous?

  117. Alex Stadtner says :

    Hi Warren,

    Thanks for voicing your opinion.

    First, for anyone to say that RF exposure from living or working near a cell tower has no health effect – ignores years of research and peer-reviewed, published health studies. I’ve met many people who suffer symptoms living near cell towers, and I myself have suffered tinnitus (ringing in the ears) for only one prolonged period in my life – when I lived near a cellular tower.

    Second, your claim that RF being lowest 100 feet from a cell tower is incorrect. Perhaps if you happen to be “in the shadow” of the RF broadcast than levels would be “lower than if you were in line-of-sight” of the antennas. But, having measured hundreds of properties near cell towers, by and large all areas near cellular towers are “higher than average” in terms of RF exposure. This is especially true where tenants in a mid-rise or high-rise building are level with a cell tower. If you can look straight out your window and 100 feet away is a cellular antenna or cell tower, the levels of RF are going to be VERY high. No doubt about it.

    I suggest you read up on health studies about RF and buy a meter for yourself. You’ll find that there is at least cause for concern from the health research, and that RF is definitely elevated within 100 feet of a cell tower.


  118. Alex Stadtner says :

    I’m sorry to hear about the proximity of your free apartment to known point sources of magnetic fields (EMF from sub station) and radio frequency radiation (RF from cell tower). I cannot say whether or not you will suffer any symptoms or illness as a result to higher-than-average exposure to EMF/RF, but it does sound like you’re probably in a home with exposure levels higher than the conservative and precautionary levels established in Building Biology and/or the BioInitiative Report.

    There is shielding or a sleeping tent you could explore to reduce exposure of RF during sleeping hours, but there is little you could do to mitigate the high magnetic fields from a substation. Magnetic field shielding of this magnitude is generally cost prohibitive.

    Without taking measurements it’s impossible to say how high the exposure is in your apartment, but gauging from rules of thumb you probably are “above average” due to the proximity to the sources you mentioned. I wish you the best of luck.

  119. W A says :

    You would have to climb a cell tower before you would get any significant RF exposure. In fact, the RF levels are lower within 100 feet of a tower than out a ways when the levels begin to rise at all.

  120. al tee says :

    I get a free apt in a storage bldg as a property mgr. There is a cell tower on the 2 storey bldg, and abt 20 feet outside my bedroom window is “sub-station”. There are emf and rf hazard signs posted on the panel boxes.
    I’m concerned abt my health living in such close proximity.

  121. Alex Stadtner says :

    I’m not a doctor, but I can tell you that you’ll find a lot of information about EMF Health Effects in the BioInitiative Report. And if you follow/google any of the authors they offer information about EMF health effects on their sites, too.
    Best of luck,

  122. prasad says :


    I am worrying about the EM waves effect on the human memory and the mood swings
    is it true that influence these

  123. Alex Stadtner says :

    Hi Chris,

    Thanks for the inquiry. Many folks are increasingly interested in health effects from cell towers, and everyone wants an easy answer. Here are a few comments about the radio frequency (RF) radiation emanated from cell antennas.

    1) EMF Rules of Thumb. Because RF travels in a straight line the Bau-Biologists (Building Biologists) suggest not spending much time where there is “direct line of sight” to a cell antenna. When you have a meter it’s easy to demonstrate how trees, walls, hills, etc dramatically reduce RF exposure. Soon I’ll write a blog about RF… but this principal is important. If you can see the antenna it’s probably pretty high RF relative to the surrounding areas in the shadows.

    2) You say a cell tower, which implies there are more than one antenna. Cell towers inherently radiate more RF than singular antennas.

    3) Regulated cell antennas and towers are EVERYWHERE! One only need type a city address into to see how ubiquitous this relatively new technology has become. Distance from the antennas and avoiding line-of-sight is the best you can do in terms of siting a building.

    4) RF regulatory levels. Unlike every other hazardous substance regulated by the EPA, the FCC is responsible for setting exposure limits for RF in the US. The US has very high exposure limits relative to many EU and Asian countries. Regardless of where you are in relation to a cell antenna… unless you’re less than 10ft away… it’s extremely unlikely you would be anywhere near the US regulatory limits for RF. Ask folks from Israel, Sweden, Germany, etc… “is this high?” They’ll say yes. But ask a US regulator and they’ll say the levels within line of sight of a cell tower are well below exposure limits and safety concerns. For a second opinion, check out the BioInitiative Report that recommends precautionary exposure levels at a fraction of US limits.

    5) With a good RF meter you can take measurements yourself, but it takes training to properly use such meters and we’d suggest a formal survey by a trained professional. This link helps you find certified Building Biology Environmental Consultants in your area. We also provide RF site surveys.

    6) If you do buy a place near a cell tower, or if someone adds a tower after the fact, there are myriad ways to shield RF and create a living sanctuary regardless of this external source. Outdoors is almost impossible to shield effectively unless you can create a visible screen between you and the source, but any building material is capable of being shielded effectively for blocking (significantly reducing >90%) incoming RF. We provide EMF/RF design consulting for clients all across the country.


  124. Chris says :

    We are looking at buying a property that is some what near a cell tower. Is there a way to measure field emitted from tower or a recommended distance from tower to be outside field. This is raw land so there is no other fields that we would be concern with until we build on the property.

  125. Alex Stadtner says :

    Hi Nathan,

    Thanks for the nice note. Not being doctors we do not make any health claims. The BioInitiative Report is updated every few years, and this compilation of peer-reviewed and published studies will start to show you what possible health impacts exist.

    Check out this blog from almost 2 years ago:

  126. Nathan says :

    Hi just wondering if anyone knows what harm and effects Emf has on a person.
    For I live very near a pylon and my wife has been having some issues and now im getting the same issues.which is why im starting to think its the pylon causing these started with my wife and now me and my wife is at home more than me .so explains why she got issues first.So im now very worried about my son too .are we just getting older or is there an issue with distance to living near pylons.

    Thanks guys really would be nice to know

  127. Alex Stadtner says :

    Hi Vonnie,

    Thanks for the note about EMF “safe” limits. We’re not doctors so we generally defer to other established thresholds. This other blog highlights a few allowable limits by different organizations:

    In general we defer to the Building Biology and Austrian Medical Association guidelines:
    Magnetic Fields = 0.2 milliGauss (mG)
    Electric Fields = 0.3 Volts (ambient) or 100 milliVolts (body voltage)
    Radio Frequency (RF) Radiation = 10-100 microwatts per meter squared (uW/m2)*

    These precautionary values are of course far lower than what the FCC or OSHA agencies believe is of concern in the US. All of these thresholds are supported by peer reviewed publish studies showing biological effects at these levels or above. The BioInitiative Report is a great compilation of EMF health effect studies.

    *The RF level can be very difficult to attain in urban areas, and the level has recently been raised. I’m actually not certain of the current standard for RF, but I consider anything under 100 uW/m2 relatively low, and anything under 10 uW/m2 to be excellent.

  128. vonnie says :

    what are the considered “safe” limits for electrical, magnetic and microwave readings? Inside vs outside?
    Thank you so much!

  129. Michelle says :

    Hi there,
    I was interested in this page because I have recently become concerned at work about what potentially harmful electric or electro-magnetic fields may exist at my workspace. I have worked here for over 5 years, and during that time my desk has always been considered the ‘bermuda triangle’ of technology – all wi-fi devices don’t work at my desk, and other unsual things happen from time to time, that I have just put down to bad reception, and anomolies. However, I have recently been plugging in my mobile phone to recharge at the 6 point power board that sits on my desk, behind my computer. (I sit in a corner space, with a lap top connected via ether net cable and 2 additional screens, and the power board also powers my landline phone, a printer, a walkie-talkie and another hands-free phone). Whenever I plug my phone in there to charge, it very soon goes to ‘SOS’ instead of my provider, but once I remove it and move it away, my provider comes back. This does not happen when I charge it at home. People one desk away from me on either side get wi-fi reception OK, and get their service provider OK, but they don’t have the power board set up that I have, only their computer with 1 screen and their landline plugged in. I really don’t know anything about electric/electro-magnetic fields, and whether my situation is affected by these at all, so I thought I’d ask the experts! Any advice you can offer would be greatly appreciated.

  130. Sophia says :

    Hello Sebastian,

    That would be us! Glad you reached out.


  131. Sebastian Parker says :

    Does anybody have a recommendation for resources/companies out there who do home EMF and EMR assessments? I would prefer to hire an expert to detect whether my home or work space is potentially harmful.

    Thanks! I live in San Francisco

  132. David Smith says :

    So what are the gross readings that can be considered harmfull >01 MilliGauss—100miligauss? What is considered a high alarm reading?

  133. Cameron Das says :

    @Paul L,
    The problem with Smart Meters is not so much magnetic fields, but the RF radiation that they constantly transmit and the dirty electricity they produce. Replacing the Smart Meter with an Analog Meter will not do much of anything for the magnetic fields, though it will reduce the RF radiations from the electric meter to essentially 0 and reduce the dirty electricity levels of the home. That being said, there are a few things that can be done that will have greater reducing results that buying Mu Metal shielding.

    High magnetic fields are typically due to two mains factors: 1) high electrical current draw, 2) distantly separated hot and neutral wires. This is part of the reason that older homes with Knob and Tube wiring can have high magnetic fields.

    Modern NM (Romex) type wiring is good due to the fact that the hot and neutral wires are only about 1/8th of an inch apart. However, when the NM wire comes into the electrical panel the hot and the neutral wires are separated and oftentimes connected to parts of the panel several inches or more apart. Most electricians are not concerned about magnetic fields and so do this out of time convenience.

    Hiring an electrician to rewire your electrical panel so that the hot and the neutral lines of the same circuit are installed in the panel at points near each other greatly reduces the magnetic fields in most cases.

    Mu Metal is an expensive and somewhat effective option. My personal experience with Mu Metal shielding shows typically a 30-50% reduction in the magnetic field. However, just moving wires around in the panel so that it is arranged in a ‘cleaner’ fashion will oftentimes achieve a much greater reduction in the magnetic field.

    Aside from that, the electrical panel being 12″ from your wife’s head is still very close, in general. We usually suggest that a minimum of 3′ from most point sources / 5′ from electrical panels be observed for sleeping areas or work areas. If you can do anything to rearrange your house so that your sleeping area is further from the electrical panel, that would be greatly encouraged!

  134. Paul L says :

    I recently had my “smart meter” removed and replaced with an analog meter. I am still getting very high readings from my Tri-Field 100xe. I am guessing that my next option would be to “Shield” the meter with Mu-Metal or possibly stainless steel as this meter is installed
    12″ from my wife’s head where she sleeps. Any suggestions?

  135. Alex Stadtner says :

    Thanks for the good blog about EMF, Cameron.

    The difference between “EMF detectors” vs. “EMF meters” is also an important part of measuring EMF 101.

    Detectors make noises, vibrate, or flash lights when in the presence of “something.” A mag-stick is a good example of a magnetic field detector. It makes a racket when in the presence of higher magnetic fields. A simple voltage detector, available for $15 at your local hardware store, is an example of a voltage (electric field) detector that can make noise, vibrate and/or flash bright lights when around sufficient electric fields. A simple compass is a good detector of DC magnetic fields. Detectors are qualitative and show relative strength of “x,” but do not provide an actual qualitative measurement.

    Meters provide qualitative data. Anything with a digital or analog readout of actual units could be considered a “meter.” Meters require calibration, and – like most things in life – you get what you pay for. Generally more precise and accurate meters cost more. Meters are good if you really want to know the actual exposure level and compare your space to international allowable limits, etc.

    We mostly rely on meters for our business. However, to be honest, with the right training and a few good detectors we could provide most of the same advice. If you find a “hot-spot,” don’t sleep by it! Detectors help identify sources of stronger radiation, and distance from the source is a guiding principle in limiting exposure to EMF.

Leave a Reply