EMF Best Practices

by / Wednesday, 27 March 2013 / Published in Green Building Consulting
Demand Switch - Low EMF Best Practice

This is part of the series on the Healthy Home Standard, and this second part about EMR is a follow up from an earlier post (EMF Rules of Thumb). EMF best practices covers low frequency electric and magnetic fields, as well as Radio Frequency (RF) radiation.

EMF best practices are intended to reduce exposure to Electromagnetic Fields (EMF) and Radio Frequency (RF) Radiation – often combined in the term “electromagnetic radiation,” or “EMR”. These low-EMR measures include how to install wiring, heating/AC, and other tips on items such as transformers for pool or outside lighting. For information on how far to locate a building from known point sources (e.g., power lines, cell towers, electrical transformers), please visit the previous EMF Rules of Thumb blog.

I find these guidelines useful for pre-purchase real estate decisions, and also for healthy building construction and remodels.

EMF Best Practices – Part 2 of 2

Electrical System Installation for Low-EMR:

  • All rooms are wired for high speed Internet using Cat 5e or 6 cable
  • All rooms wired for phone service using shielded cable
  • There is no wireless Internet or cordless phones in house
  • There are no cell phone booster stations in house
  •  All circuit breakers are accurately labeled as to area/devices serviced
EMF Best Practices

No Cell Phone Repeater Stations – This Nice Signage from Doctor’s Office

Low-EMR Heating Via Forced Air:

  • If there is air-conditioning, the AC condenser & Freon lines are more than ten feet of any point on any bed or any HUR
  • If there is a forced air system for ventilation, heating or air-conditioning, the Air Handling Unit (AHU) or Forced Air Unit (FAU) fan motor is located more than 10 feet from any point on any bed or any HUR

Low-EMF Electric Radiant Heat:

  • Ceiling or floor radiant electric heat designed to cancel magnetic fields
  • If heat is by electric baseboard, electric baseboard heaters are located more than 5 feet any point on any bed
EMF Best Practices

Low EMF Electric Radiant Heat – ThermoSoft Has An Option

ThermoSoft seems to have a good low-EMF electric radiant heating system that accounts for both magnetic AND electric fields. However, it’s not “zero-EMF” as they claim.

Low-EMF Wiring In A Bedroom:

Using only one of the following 3 strategies is necessary – each strategy is intended to minimize electric fields.

  • Wiring above, below, around bedrooms is metal clad (MC) cable or electrical metallic conduit
  • Wiring above, below, around every bedroom can be shut off with a kill switch
  • Wiring above, below, around every bedroom can be shut off with a remote control switch operating a relay located at the electric panel
EMF Best Practices

Remote Control Demand Switch – EMF Best Practice for Reducing Electric Fields in a Bedroom

Pool and Spa Pumps & Outdoor Lighting Transformers

  • If there is a pool or spa, the pool or spa pump or outdoor lighting transformer is located more than 5 feet from any bed or any HUR

These EMF Best Practices have been established for many years, and we have seen them implemented successfully in projects around the world. They are tried and proven best practices for reducing EMF. I’m grateful to the Building Biologists that came before me… and not only created this handy resource, but also were kind enough to share!

If you’re doing a remodel or building from scratch, following these best practices will get you a “better than average home.” To take it to the next level, consider hiring a Healthy Building Consultant!

If you agree that the USGBC/LEED should consider EMF in their “green building rating system,” please join us in signing this petition.

Backstory : LEED Denies EMF Credit

Petition : USGBC Accept EMF Credit

30 Responses to “EMF Best Practices”

  1. Alex Stadtner says :

    You get what you pay for. Call Electric Sense, Safe Living Technologies and LessEMF for more specific recommendations on your budget. Their sales folks will walk you through their products and help you make an educated decision on which EMF meter is best for your needs.

    In general, when people say EMF they are referring to low-frequency magnetic fields. Technically, however, electromagnetic fields is a very broad term. At the very least, loosely used, the term “EMF” should include low-frequency ELECTRIC fields and MAGNETIC fields. “Dirty electricity,” or “high-voltage transients,” or “electromagnetic interference (EMI)” are harmonics in slightly higher frequencies than our 60 Hz power supply in the US. Dirty-electricity is simply electric and magnetic fields that are higher than 60 Hz but lower than Radio Frequency (RF) radiation. Unlike low frequency electric and magnetic fields, and RF and ionizing radiation, there is no uniform unit of measurement for dirty electricity. It’s a little bit more of a mystery and there haven’t been as many health studies focusing solely on dirty-e. However, anecdotally, many people with electrical hypersensitivity (EHS) respond well and sleep better with dirty-electricity filtering or “line conditioning.”

  2. What is the best lay person's device for measuring magnetic fields in the home? says :

    Thanks for all the info on this site. I am not highly technical but would like to measure fields in my home (I have small children.) What is an easy device that would be appropriate for a beginner? Incidentally, can you shed some light on the differences between dirty electricity and emf?

  3. Alex Stadtner says :

    When replacing your heater there are many, many variables to consider. You need a good consultant or excellent contractor. Best of luck.

  4. Vahe says :

    Hi there. Thanks for the information. I’m glad this community is getting stronger and people are taking this stuff seriously. I am just looking for a replacement for my electric heater. My house is not isolated well and my room is particularly cold with the main heating system not connected. Any suggestions?

  5. Alex Stadtner says :

    It depends on the systems and how they’re wired. With all refrigerant lines, stray voltage can be a problem if there are other wiring errors in the building. Locating systems away from primary sleeping areas… and shielding where necessary… are best practices. Besides that you’d have to test the specific equipment being specified.

  6. roman says :

    Great article! I am building a home that has to be emf safe for my wife. How safe are mini-split heating and cooling systems in that regard. What about electrical infrared radiant heat panels?

  7. Alex Stadtner says :

    Congrats on the home purchase.
    Great that levels go way down with the circuit powered off. That means the source or problem is interior to the home and under your control.
    I assume you’re measuring magnetic fields. If it’s electric fields, the only thing you could do is shield or install a demand switch or simply turn the circuit off at night. But if you’re concerned about magnetic fields it may be a wiring error… or simply how the box/switch are wired behind the covers. Don’t know enough about the situation to provide more specifics.
    Magnetic fields are load-dependent. So you should be able to turn on/off lights, fans, etc and see the same drop in magnetic fields (EMF) as you do when you turn off the circuit.
    Good luck,
    Healthy Building Science

  8. Steve G says :

    I just purchased a home that was built in 1996. A bedroom has the breaker box in it. When I turn off the circuit for that bedroom’s lights and outlets I get very little Emfs except when I get very close to the actual breaker box i.e. a foot to 18 inches which I would expect.

    When I switch on the circuit for that room then I have a fairly high EMF readings near the wall that the breaker box is on and on the opposite wall in
    This room is approximately 11 x 11′. So, it would seem that the house wiring into the breaker box does not have a particularly bad problem. What is the problem is the actual leg that serves that particular room. Do you have any suggestions to instruct and electrician to figure out or resolve why this particular leg is radiating so much EMFs ?

    Thank you in advance

  9. Alex Stadtner says :

    For most folks setting up a DC fan would be impractical.
    However, all other things equal, I think I would suggest a DC motor.
    But if it costs an arm and a leg or is too complicated – don’t bother. We don’t usually see ceiling fans emitting that much EMF.
    Good luck,

  10. Becky says :

    What would you recommend for ceiling fans. Would an AC or DC motor be best…all things considered. Thank you very much.

  11. […] for an Innovation in Design (ID) point for a LEED Homes Platinum project that really followed low-EMF design and construction best practices. This healthy home remodel project implemented far more than the average number of precautionary […]

  12. Alex Stadtner says :

    You are most welcome!
    Glad the content is useful for you in attaining a more health-supporting indoor environment.
    The Building Biology general language and rule-of-thumbs for keeping condensers and refrigerant lines >10 feet from High Use Rooms (HUR) is primarily about magnetic fields. Some mechanical systems may create elevated magnetic fields when they are in use, and wiring errors that result in stray current on refrigerant lines are common and can contribute to significantly elevated magnetic fields over a large area. Sound may also be a concern. So simply locate the condenser as far as possible from the sleeping area. Doing some electrical and EMF testing upon completion of the installation should verify if there are any wiring errors. But that takes some EMF testing equipment or an electrician or handy-person who knows what they’re doing.
    Kill switches are a good idea. Good luck sources those right now. Demand switches are in high demand!
    And make sure that you turn off all active lines running under/over/behind each room you want to protect. It may require “killing” more than just the lighting and plug circuits in your sleeping area to significantly reduce electric fields. Sometimes, due to the wiring layout of the building, you have to turn off other circuits to reach building biology goals for sleeping areas.
    And the wood stove – can be a source of VOCs and fine particulates. So ideally it has a sealed faceplate and dedicated supply air.
    Good luck with your baby and nest preparation,

  13. Rebecca says :

    Thank you for your wonderful articles! I am in the process of building my first home and with a baby on the way a safe home somehow seems extra important.
    In reference to your statement, “If there is air-conditioning, the AC condenser & Freon lines are more than ten feet of any point on any bed or any HUR”, could you please explain why?
    I am considering a ductless split system to heat and cool. The condenser is outside and the evaporator/air handler (fan powered) is installed on an inside wall. The units are connected by refrigerant tubing and electrical lines. The compressor is a DC inverter driven rotary. What possible EMF issues could the ductless split system present and how might I address them?
    I am finding it hard to comply with the many “stay 10 feet away from beds or HUR” recommendations, as it is a 850 sq.ft. house consisting of only 2 small bedrooms, 1 bath, and an open kitchen and living room. Thankfully it’s a new build so I can at least wire all rooms to be on kill switches and a wood stove will handle the winter. Thanks again!

  14. Alex Stadtner says :

    Yes. Any grounded metal “shielding” will prevent significant electric fields from being emitted around the live cable. You can test this with a simple “voltage detector.” A live wire in regular romex will set off the voltage detector. Metal clad wiring that is not grounded will really set off the voltage detector. But once you ground the metal shielding the voltage detector shouldn’t detect any voltage (electric fields.)

  15. Sue says :

    Is steel armored cable with aluminum bonding strip grounded thru metal jacket (like southwire AC cable) the same as MC cable for emf protection? Thanks

  16. Alex Stadtner says :

    A satellite dish is a passive receiver that does not, by itself, produce any radio frequency (RF) signals. In general we are not able to measure anything “coming off of” a satellite dish. It is essentially an antenna, like a GPS or radio, that receives a signal but doesn’t generate a signal of its own. There are of course exceptions to the rule, such as a very strong RF signal using the dish as an antenna. But this is rare and not generally a significant source of RF indoors. Wi-fi, wireless phones and printers, cell phones, and smart meters are generally much stronger internal sources of RF/EMR.
    Be well,

  17. Ruth Ruddock says :

    Can you please tell me if having a satilite dish on the roof providing source for our computer system (Hughes.net) is problematic for me…I have electrohypersensitivity….thanks!

  18. Alex Stadtner says :

    Thanks, Bev!

    It’s tough with California Energy Code (Title 24), which requires either high efficacy (LED or CFL) or dimmers in many locations. The CFLs and dimmers produce high voltage transients (dirty electricity). We’ve had several clients have to waste money and install dimmers for their final code inspection… only to remove them immediately after passing the inspection and replace them with simple on-off switches. The alternative is to install line conditioners (dirty-electricity filters) on any circuit with dimmers. Unfortunately, with lighting circuits, there are often aren’t outlets so the less expensive DIY filters are off the table and a more advanced line conditioner often must be installed by a licensed electrician.

    Keeping a building low-EMF aint easy, and our state energy code isn’t helping.

    Let’s see what sort of follow up blog Cameron can produce about dimmers!


  19. Beverly Alexander says :

    Hi Alex and team, I love your blog! It would be great to have a future one on the topic of dimmer switches since they are so popular now in homes. Should they all be removed? What brand is best for the replacement, etc. Thanks! A grateful follower. Bev

  20. Alex Stadtner says :

    Distance from the source is your best bet for reducing exposure to magnetic fields (EMF) from the breaker box and baseboard heater. You could spend a pretty penny on magnetic field shielding material which may eventually reduce exposure by 30-60%, but a little distance will probably have an even more dramatic impact. Move the headboard away from the source… even an additional 6-18″ will make a difference. You could also sleep with your head at the other end of the bed. Best of luck,

  21. Diane says :

    I am on disability and I have compromised immune system health issues. The house I am living in has the breaker box in the bedroom located five feet from the head of the bed. The same bedroom has baseboard heat located ten feet from the head of the bed. What can I do to reduce/remove exposure as there are no other room alternative to sleep in?

  22. Alex Stadtner says :

    Hello YM,

    Hydronic radiant heat – via hot water delivery – is the preferred method of heating for Building Biologists.

    Using AC electricity to generate heat is less efficient and creates elevated magnetic fields. Most electric radiant heat wiring systems just send one wire through the system – essentially a “hot wire without it’s corresponding neutral.” The separation of the hot and neutral, combined with the unusually high amperage (current flow) required for such systems, creates unusually high magnetic fields. I’ve measured over 100 milliGauss (mG) at knee height over some systems.

    Details of your home would dictate the best solution. Here are a few options:
    1) use hydronic heat
    2) only preheat floor when room is not in use, then turn off system when entering room
    3) select a “low-EMF” version and wire it properly

    The “low-EMF” version of ThermoSoft has shielded cable (for electric fields) and runs hot and neutral wires right next to each other (magnetic fields) through the whole assembly. It does significantly reduce the magnetic fields as long as the system is wired properly. I don’t recall testing the SunTouch system or recording any measurements to reference. If you must go with electric I would pick a “low-EMF” version.

    We’re happy to consult by the hour if you have additional questions.


  23. Yessica says :


    I want radiant heating in our new home in Jacksonville, Florida but I’m concerned with the information I’ve learned thus far about its EMF output. I noticed you briefly mentioned ThermoSoft’s low EMF. How does it compare to SunTouch’s system? Which is the better option in-slab wiring or over-concrete mats? Would you recommend an alternative solution for warming up tile floors? Thnx. -YM

  24. Lady Moe says :

    This the reason why I love this site.

  25. Alex Stadtner says :

    Hello Sten,

    Many electrically hypersensitive people react well to reducing dirty electricity (aka: “high-voltage transients,” or “electrical noise”) e/m-field exposure around where they spend the most time. This may mean shielding or turning off the circuits around a bed at night, or perhaps additional dirty electricity filtration.

    There are larger systems designed mostly for audio/visual clients wishing to reduce “electrical noise,” but the vast majority of people can only afford the plug-in versions which are easy, do not require an electrician, and cost a lot less than the larger filters.

    In the US there are only two major providers of the plug-in dirty electricity filters: Stetzer Filters (www.stetzerelectric.com/) and GreenWave Filters (www.greenwavefilters.com/)

    Stetzer was first to market, but their current version is a little more expensive than GreenWave’s, and the GreenWave filters have the advantage of still being able to use the outlet jack because they have a plug-in spot on the bottom of the filter.

    The GreenWave EMI Meter is actually quite good at “measuring dirty electricity.” It has an audible feature which is really nice, an it measures in milliVolts (mV) instead of some made up unit from Graham-Stetzer.

    I’d imagine these systems would work on your voltage and could be used in conjunction with an outlet adapter in the EU, but you may want to speak with their customer service reps before purchasing.

    Be well, and good luck with the electrically sensitive client!


    P.S. One our most experienced EHS doctors in the US frequently suggests patients try out “Earthing” too. It may be worth a try. http://www.earthing.com/ This is a very controversial strategy for many Building Biologists (Bau-Biologist), but there’s no denying that it actually helps many (not all) people suffering from EHS.

  26. Sten says :

    Thanks for the reply Alex! I live in Scandinavia but I do believe I have heard about the SunnyBoy here as well. Could you point me to any specific filters or filter solutions that you would recommend? Makes and models? That could be very helpful.A woman here is so ill she can’t stay in her (eco-)house when the solar power is operating and she is begging for help, so I am trying to find some solutions that could help her. But there is very little information to be found on this subject, so any help or tips would be greatly appreciated.
    All the best /Sten

  27. Alex Stadtner says :

    We have seen how some inverters are “dirtier” than others, and produce significantly higher levels of high-voltage transients. The SunnyBoy inverters are among the best – meaning they seem to produce less dirty electricity than many other inverters. As for mitigation, there are “filtration” approaches (aka. “Line Conditioners”) that can be applied to a single circuit, or even at a subpanel level. It’s interesting work!

  28. Sten says :

    Very good overview!

    You seem like a big team. Do you have any experiences with solar power inverters, and ways to mitigate or reduce the often high levels of dirty electricity that they create?

    I would love to hear about your experience in that area.

    All the best /sten

  29. David Sasse says :

    Brick and Insulation will not shield Magnetic fields. The best suggestion I have is to measure the magnetic field strength around the bed to see how strong the field is in that area. In lieu of that, I recommend placing beds a minimum of 5 feet from point sources such as sub-panels and high current draw appliances such as an A/C unit. – DLS

  30. Jan Underwood says :

    The head of my grandson’s bed is on an outside wall; the home’s A/C unit is on the same wall. Will the home’s brick and insulation shield him from EMR as he sleeps?

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