Magnetic Field Detector Recommendation

March 3, 2010 1:02 PM

My wife and I are buying a house. We have a young child. We want to know how much magnetic field a house we're considering is subject to. I Know, I know, there is NO conclusive proof for or against high voltage power lines causing health problems. BUT, I'm in the "just in case, better safe than sorry school." SO, can the community recommend a good 3 axis magnetic field detector under $500 that can tell me AC (and perhaps DC) magnetic field strength in milligauss and/or microtesla and start at around 1mG (and up) in detection range.
posted by apark to Science & Nature (19 answers total)

It seems like for $500 you could hire someone to do the testing rather than have some object you use only once hanging around your house. That way you can get a professional opinion about the dangers of the fields. Try looking for electrical engineers in your yellow pages.
posted by JJ86 at 1:07 PM on March 3, 2010 [1 favorite]

Response by poster: Well, I'm thinking that we'll keep this device around to be able to see in the future if any other devices has an unusually high magnetic field in my child's room... (or any other room for that matter)
posted by apark at 1:10 PM on March 3, 2010

Best answer: I actually use a magnetometer from AlphaLab in my lab, mostly because it was a fantastic deal for a NIST-traceable gaussmeter. If these work for my purposes, they should almost certainly work for your paranoia-reduction-activities.
posted by JMOZ at 1:19 PM on March 3, 2010 [1 favorite]

If anything, the tool might be useful if you have computer issues. A friend working at the PC repair shop at the local Staples was wondering why they kept losing monitors & PCs at one of the service desks, but not the other... when she noticed her voltmeter picking up a charge off the table surface, things became a lot clearer. The nearby security system was emitting a very, very powerful EM field that was enough to affect electronics on the table it was next to, and wreck them after prolonged exposure.
posted by GJSchaller at 1:44 PM on March 3, 2010

If you're concerned about magnetic fields from power lines, you should understand that field strength follows an inverse-square law...that means every time you double your distance from the source, you get one-fourth the field strength.
What that means in a practical sense is that unless your house is directly under a major high-voltage tower, your biggest magnetic field source is going to be the power inlet stack to your house, and you can't avoid that...every house has one and every house has the same fields.
The best thing you can do to protect your child is to make sure that your child's bedroom is not the one adjacent to the inlet stack, and that no beds are adjacent to the stack on the other side of the exterior wall.
posted by rocket88 at 1:53 PM on March 3, 2010

Mod note: A couple comments removed. Be helpful or stay out of the thread.
posted by cortex (staff) at 1:57 PM on March 3, 2010

I'm going to save you 500 dollars and give you peace of mind for free:

In 1996, a committee of the National Research Council concluded:

Based on a comprehensive evaluation of published studies relating to the effects of power frequency electric and magnetic fields on cells, tissues, and organisms (including humans), the conclusion of the committee is that the current body of evidence does not show that exposure to these fields presents a human-health hazard. Specifically, no conclusive and consistent evidence shows that exposures to residential electric and magnetic fields produce cancer, adverse neurobehavioral effects, or reproductive and developmental effects [8].

Even if you got a proper tool, I seriously doubt you have the methodology or scientific rigor to use it properly. You'll just draw whatever conclusions you feel are psychologically pleasing from whatever data you collect. Spend that $500 on your kids next birthday present.
posted by damn dirty ape at 2:01 PM on March 3, 2010 [18 favorites]

I can't recommend a detector, but this NIH report (PDF) mentions on page 51 that Many U.S. electric utility companies will measure fields in their customers' homes and help them to identify sources of high fields. Might be worth checking your local utilities practices and see if there's a services you can use.

That same page also mentions some of the characteristics of residences with exposures. You might take those into account during your house hunting.
posted by IanMorr at 2:06 PM on March 3, 2010 [1 favorite]

Response by poster: Ha ha. I realize that this type of question often draws responses similar to questions like, "Should I get a Mac or a Windows PC?", "Which editor is best vi or Emacs?"

Having spent considerable time on Google researching this issue, I realize that there is no definitive proof that EMF causes cancer in children. BUT, there is really no definitive proof (you know how hard it is to prove a negative.) that it doesn't either.

In any case, even if it doesn't cause cancer in my son, it might affect the resale value of my home if and when I decide to sell (this home which I haven't even bought yet!) So, I want to armed with data (this house is xyz meters away from power line and the EMF in the house from that source is about abc mG.) and make an informed decision base on that.

Thanks for all your input!
posted by apark at 2:27 PM on March 3, 2010

Not sure I understand the question correctly (and I confess that I haven't looked into this issue at all): do you really care about ~1 mG fields? Probably you know this, but the earth's magnetic field is of order a gauss. Your kitchen magnet is around 10-100 Gauss. Given that, it seems to me like you will drive yourself nuts chasing mG signals, and that any signals you measure are as likely to be noise as anything else (unless you are very, very careful and using lab-grade equipment).
posted by chalkbored at 2:58 PM on March 3, 2010

If you really want to drop some cash on a gadget for your peace of mind, here's a nice-looking one. One of the reviews is even a realtor who used it to test houses for other families that believed in that sort of thing.

Honestly though (and I know you didn't ask for my opinion :) ), there are MUCH better ways to spend money if you want to protect your family from cancer. Get your home tested for radon! Buy organic clothing! Eat organic foods! Enroll your kids in some expensive tennis program or something.

I realize it's not a dichotomy, and you may be able to do all of those things AND get a magnetometer, but of all the things that might give you cancer, ELF EM fields is way way down there on the list, probably near the position of "coffee".
posted by Salvor Hardin at 3:10 PM on March 3, 2010 [4 favorites]

I realize that this type of question often draws responses similar to questions like, "Should I get a Mac or a Windows PC?"

Well, that's close. A better analogous question would be, "Can I buy a PC where the printed circuit boards inside are red instead of green? I know most manufacturers still use the green PCBs but the red PCBs must have been invented for a reason and I'd rather be safe than sorry." If there is a difference between the electrical properties of different-colored circuit boards, it's smaller than other differences between typical circuits. If there is a difference between the biology of people living in weak, low-frequency electromagnetic fields and people living in the earth's natural field, it's smaller than other differences between the biology of typical people. You can worry about either of these things if it suits you (but you shouldn't).

Probably your best suggestion is JMOZ's link to AlphaLab. If you buy a meter (those really are good prices), don't just measure in your prospective house: measure in your current house, in your friends' houses, in restaurants, in the hallway of a hospital. Look for local variations in the field near and far from power cables and outlets, especially when running high-current devices like vacuum cleaners. Try to come up with a kitchen-type experiment where you can get a weak magnetic field to change anything nonmagnetic in any way at all. Let me know if you find one.
posted by fantabulous timewaster at 3:13 PM on March 3, 2010 [3 favorites]

I Know, I know, there is NO conclusive proof for or against high voltage power lines causing health problems. BUT, I'm in the "just in case, better safe than sorry school."

The earth's magnetic field is literally orders of magnitude higher than that of the power lines near your home. That is like refusing to use a granite countertop while smoking five packs of cigarettes a day. If safety is truly your concern, you should spend that $500 on smoke and carbon monoxide detectors, fire extinguishers, and CPR and first aid classes.
posted by Optimus Chyme at 3:39 PM on March 3, 2010 [5 favorites]

A very easy way to test the strength of a nearby magnetic field is to buy a fluorescent light tube and hold it up. In strong EM areas, they light up like magic.
posted by BusyBusyBusy at 3:48 PM on March 3, 2010 [2 favorites]

Yeah but radon testing may be a condition of sale. It is in my state, Pennsylvania. EMF testing is not required, and this question largely academic unless the OP s actively considering the purchase of a house located within sight of a high voltage tower or line. In which case the resale of that house might be problematic, due to the same fears in the mind of the subsequent buyer. There is a such a glut of inventory that when deciding between two houses in the same price range, why would you even be considering a house with any problems?
posted by fixedgear at 5:04 PM on March 3, 2010

You're probably looking for something fifty times better than this, but in case you don't already know about these, there are a couple EMF Detector apps for the iPhone: 1, 2.
posted by salvia at 9:18 PM on March 3, 2010

Have you considered not buying this particular house? I think if one of your rationals for doing this is resale value, no one who is, or would be, concerned with the proximity of power lines is going to take your word for the safety of said lines. So you either buy the house because you don't care and will sell to others who don't care, or you look for another house where this isn't an issue. Based on your concern (warranted or not), I would think looking for a different house would be the better long-term strategy.
posted by qwip at 12:17 AM on March 4, 2010 [1 favorite]

In any case, even if it doesn't cause cancer in my son, it might affect the resale value of my home if and when I decide to sell

I can't recommend a magnetic field detector but I've bought 2 houses in the last 3 years and looked at at least 40 while house hunting. I can almost guarantee you that the subject of how much a magnetic field a house is subject to will NEVER come up if/when you sell the house. Unless you're living right under power lines or very close to them it will not affect the resale value of your house. I can't speak to your concerns about health issues though.

We did radon testing in both houses we bought just as a precaution but magnetic fields were never discussed and I think most real estate agents would have no idea what you're talking about if you brought it up.
posted by bingwah at 8:03 AM on March 4, 2010

I think there may well be carcinogenesis and other problems associated with living near high voltage power lines, but that they have nothing to do with electric and magnetic fields.

It's the herbicides you have to watch out for.
posted by jamjam at 1:52 PM on March 4, 2010