EMF Meters and Detectors

Are you serious about avoiding excessive EMF?

If you are, you will want to measure it, or at least detect it. An EMF meter or detector can be a great help in establishing just where the EMF hotspots are, in your home and workplace.

You may be able to borrow an EMF meter, or you may want to own it. If you have just one concern and want to put your mind at rest, then a borrowed instrument will probably do the job, although they can be hard to find.

But if you own one, you will probably become interested enough to use it often. In my case, originally I wanted to do a complete survey of my house, and my office. Since then I often bring it out when a new electrical appliance comes through my door!

Also, when it becomes known that you have an EMF meter, you will be surprised how many of your friends want you to measure around their desk at the office, or areas in their homes. Even the ones who say they don't believe that EMFs do any harm!

In fact, seeing a reading on the EMF meter convinces many previous skeptics that they need to be more careful about electromagnetic radiation. It's a good way to help spread awareness.

EMF Meter or Detector?

There are different kinds of EMF meter, and no single instrument does everything. What do you look for?

Let's start with the difference between a meter and a detector. The two words can mean the same thing, but usually a detector has an audible alarm or visual alert or both, but doesn't provide an actual measurement. An emf detector is usually a small device, which you can carry around with you wherever you go, in a handbag or pocket, for example. It alerts you when you enter a high-emf area. On some models you can adjust the threshold level.

An emf meter will measure the electromagnetic radiation and display the reading on a dial or a digital display. Typically you don't carry it around with you everywhere you go - people might think you were slightly weird!

For me, the emf meter is the more useful item, because when I find a high-radiation area, I generally want to know just how "hot" it is. But the emf detector does have its place, and one factor in its favour is cost - etectors are usually cheaper than meters.

Electromagnetic Radiation Exposure Guidelines

Having a meter is great, but if you look for it, you are going to find EM radiation in your home and workplace. So the first question you'll ask when you start using your meter is: "Is this EMF level dangerous? How much EMF is too much?"  

Our free EMF Guidelines document may help you to answer these questions. It takes the form of an Excel workbook Electromagnetic Radiation Exposure Guidelines which you can download. (It's only about 90 kB, so it downloads quickly.)

Types of EMF Meter

'Terminology is not always consistent from one manufacturer to another. For example, an emf meter may also be called an AC  gaussmeter, an electromagnetic field meter, a field strength meter, an electrosmog meter or an emf detection meter. All of these terms can describe the same instrument.

But you probably don't want to buy a "natural emf meter" (used for detecting the earth's static magnetic field, and for ghost-hunting) or a DC gauss meter (used to measure the strength of static magnets). Although ghost hunting could be fun!

AC EMF meters (the kind you want) tend to fall into three main groups, depending on their purpose. (You would need one from each group if you want to cover all electromagnetic radiation health risks.)

By the way, these meters also make excellent gifts for the man in your life.

1. Low-frequency EMF meters

These devices are suitable for measuring radiation from

• mains electricity,
• power lines,
• high-voltage lines, 
• electrical installations, sub-stations and transformers,
• house-wiring,
• domestic appliances,
• TV's,
• computers,
• office equipment,
• vehicles (cars, trains etc).

This type of EMF meter is very useful, because these sources of low-frequency radiation, when excessive, can have very destructive long term effects on your health. That is why I recommend that each household should have a low-frequency EMF meter. Here are some specific devices you can buy with confidence:

Trifield Electromagnetic Field Meter - This is one of the oldest (it looks it) and best meters on the market. It allows you to test separately for the electrical field and the magnetic field - both components of electromagnetic radiation.

The Trifield has two ranges for magnetic radiation, (high and low sensitivity). It measures emf in all three planes simultaneously (so you don't have to worry about taking separate readings while holding the meter in different positions) and sums them electronically into one single reading. It doesn't get easier.

It also measures radio / microwave emf, but unfortunately it lacks sensitivity in this range. The Trifield is fine for detecting emf leaking from microwave ovens, but don't try to measure the emf from a cell phone tower or radio station antenna, or wireless network. You need a purpose-built RF meter for that.

The Trifield looks somewhat clunky, and doesn't have a digital display, but sometimes an analog display gives a more immediate impression. I find it user-friendly and very quick to use. For functionality at the price, it can't be beat. When I'm doing an emf survey, the first meter I take out is always the TriField Electromagnetic Field Meter .

Lutron 822-A Digital EMF Meter - This is a well-priced digital low-frequency EMF meter. Sensitivity is great, it can measure down to 0.1 milligauss, and all the way up to 199.9 mG.

The only compromise with this meter is the fact that it is single-axis, which means that if you want to get a precise reading you have to take readings in three planes manually. If you need to, then it can be done.

Most of the time, when using an emf meter, the exact measurement of the emf is not the issue. You mainly want to get an indication of the strength of the field, and how far it extends from an object.

For this purpose the Lutron 822-A Digital EMF Meter  will serve very well. And it is very much easier on the wallet than a digital 3-axis meter.

Technology Alternatives 7021 ("Cell Sensor") EMF Meter - This is the lowest priced meter that I can find that can do a serious job. It's only a single axis meter, of course. And despite its claim to measure radio frequency EMF (for example, from cell phones), several reviewers have disputed this capability. What it seems to be measuring is the low frequency EMF associated with cell phones, microwave ovens etc, not the actual microwave component.

You need to use a probe (supplied), and readout is analogue (a needle on a scale) rather than digital. Standard 9v battery is not supplied.

The reviews I read were quite complementary about its low frequency abilities, and it seems it does a fine job of alerting you to high magnetic fields from any mains-related equipment.

Altogether, a useful product to detect low-frequency EMF, and if budget price is an important consideration for you at this stage, then I think you could do a lot worse. Technology Alternatives 7021 Cell Sensor EMF Detection Meter

2. Radio Frequency (RF) EMF meters

These high-frequency EMF meters are suitable for measuring radio waves and microwaves from sources such as

• cell phone towers
• cell phones and other mobile devices
• wireless baby monitors
• wireless networks
• wireless modems
• microwave ovens (leakage detection)
• TV and Radio broadcasting antennae.

To measure EMF from all of these sources you need a RF meter which covers the frequencies from 50 MHz or so, up to 3 GHz.

As with low frequency meters, an RF meter can be single axis or 3-axis. Each axis is referred to by a letter, normally X or Y or Z. Some of the better meters allow you to measure EMF from a single axis or in combined (3-axis) mode.

Better meters have a flat response across the frequency range, and high sensitivity so that they can detect low levels of radiation (for example, from a cell phone tower 500 metres away).

Some RF meters are designed mainly for professional use and tend to be very expensive. You probably don't need one of those. But you do need a serious instrument whose readings you can trust.

Extech 480836 RF/EMF ("Electrosmog") Meter This is a three-axis instrument, which can also read individual X, Y and Z axes. Frequency range is a broad 50 mHz to 3.5 gHz. Sensitivity is excellent (20 mV/m). Readings can be instantaneous, averaged or maximum. Your choice. You can also set your own level for the inbuilt audible alarm, .

The meter measures the electrical component of the radiation which it displays in volts or millivolts per metre (V/m, or mV/m). But you may switch the meter to calculate the equivalent magnetic field strength reading, which then displays the result in Amps per metre.

It can also calculate power density readings and display them in Watts per square metre (W/m2) or milliwatts per square centimetre (mW/cm2).

Altogether a very flexible and useful emf meter, with a clear 4 digit display (with back light). My only criticism of this meter is that it seems to slowly run down the 9 volt battery, even when the meter is switched off. So it's best to disconnect the 9v battery when the meter is not in use. Fortunately it's easily accessible.

This meter certainly isn't cheap, but considering its features, it offers excellent value. Extech 480836 RF/EMF Meter

3. Meters for Measuring Nuclear Radiation

None of the meters described above is suitable for measuring nuclear radiation (also known as ionizing radiation).

There are meters which are designed specifically to measure nuclear radiation. They may display radiation levels in electron volts (eV) or kilo electron volts (keV) or mega electron volts (MeV).

Or they may display counts of particles detected in a time period (which is what the meter actually measures).

The most useful meters also calculate and display the expected biological  effect of the radiation dose which would be absorbed in one hour, as millisieverts per hour or milliroentgens per hour.

Images SI Inc's  Digital Geiger Counter-Model GCA-04-C

This meter will measure all types of nuclear radiation (alpha and beta particles, gamma rays and x-rays) and display the result on a 16 digit two-line LCD screen (backlit).

In addition, it offers audible clicks (which you can switch off) and LED light indication.

Range is from 1 count per minute up to 3500 counts per second. (Normal background radiation levels are between 10 and 20 counts per minute.) This meter is sensitive enough to measure radiation from natural rocks!

Includes PC  output via RS 232 socket.

Factory calibrated for accuracy. Can also be switched to display the expected biological effect in millisieverts per hour or milliroentgens per hour.

This item (and all other Geiger-counters) was completely out of stock in May 2011 (after Fukushima) but Amazon's delivery is now back to normal (December 2011).

If you are interested in this item, don't wait until the next nuclear radiation scare to buy it. Geiger-counter stock levels are never very high, and after any hint of disaster, everyone will try to order one.

(This could become a necessary survival item, but if it does, you may not be able to find one, unless you have already bought it.)

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EMF Meters and EMF Detectors