Is there a possible link between radiant floor heating systems and certain cancers?

Many people believe that nothing compares to the comforting heat of a bathroom floor warmed by an electric radiant heating system. The concept is straightforward – when installing a new bathroom or updating an existing one, you place an electric heating mat on the subfloor and cover it with tiles. The plastic mat, made from heat-resistant polyethylene, holds looped resistance wire that carries an electrical charge, transferring heat to whatever it contacts. In this case, the floor warms up, and within an hour, the entire room follows suit. It's similar to an electric blanket without the fabric. But if you've heard that sleeping under an electric blanket while it's on could be harmful, it makes you wonder if the radiant floor system might have similar health concerns.

The concern with electric blankets stems from the electromagnetic fields (EMF) they generate. Any device powered by electricity produces an EMF – think of your microwave, clock radio, floor lamp, hair dryer, and, yes, your radiant floor heating system. Before we dive into whether there’s any risk of cancer from your heated floor, let's first understand a bit more about EMFs.

An alternating electric current (AC) creates both magnetic and electric fields. Together, these are referred to as an EMF. The electric field is linked to the voltage, which propels electricity through wires, while the magnetic field corresponds to the current, which is the amount of electricity. The EMF is emitted from both the device and the wires carrying the current to the device.

Transmission power lines, often referred to as high-tension wires, and transformers emit large amounts of EMF. Transformers, which are the small black or gray cylinders on power poles, take in vast amounts of electricity from the lines and reduce it to a safe level for use in homes. In areas with underground power lines, you may see larger green boxes at street level. Some studies suggest that children living near high-tension wires have a higher risk of developing leukemia and other types of cancer [source: DeNoon]. While conclusive proof is lacking, most experts recommend minimizing prolonged exposure to high EMF levels.

If devices like clock radios and electric razors emit EMF, could they pose a health risk? Or could your electric radiant floor heating system contribute to cancer? We’ll explore these questions in the next section.

Electromagnetic Fields and Radiant Floor Heating

We've established that alternating electric currents produce an electromagnetic field (EMF). Does this mean household appliances are shortening your lifespan? The answer is unclear. Long-term exposure to weak electric fields has been shown to be harmless [source: Australian Radiation Protection and Nuclear Safety Agency]. However, the effects of prolonged exposure to weak magnetic fields remain uncertain. While there's no direct evidence linking weak magnetic fields to health issues, researchers haven’t ruled it out because we still lack sufficient knowledge about long-term EMF exposure. Studies in animals have indicated that chronic magnetic field exposure can influence hormone and enzyme levels [source: Australian Radiation Protection and Nuclear Safety Agency]. While these findings are not considered a health risk, the possibility of it contributing to cancer over time remains under investigation.

Studying the effects on humans is more challenging. Cancer is caused by a variety of factors, so it’s difficult to isolate EMF exposure as the sole cause. There’s also a long delay between exposure to a cancer-causing agent and the development of the disease, further complicating conclusive results in human studies. So far, research has suggested that weak EMF exposure does not correlate with cancer. A 2004 study by Health Canada found that while electrical devices and power lines can generate weak electric currents that pass through the body, these currents are smaller than those naturally produced by the brain, heart, and nerves, and are not linked to any known health risks [source: Health Canada].

If this is the case, why do health experts recommend avoiding close and prolonged exposure to even weak electromagnetic fields? Don't sit too close to the television. Don’t stand directly in front of the microwave if you're pregnant. Don't sleep under a running electric blanket. The simple answer is that caution is a smart approach. Some appliances emit more EMF than others, and since we know microwave ovens leak EMF, it's sensible to maintain some distance. Electric blankets, for instance, generate an EMF that can penetrate the human body up to six or seven inches. If test results are even slightly inconclusive, it’s wise to avoid excessive EMF exposure.

When it comes to electric radiant floor heating systems, most manufacturers take extra steps to ensure the wiring is shielded, reducing potential health risks. On average, Americans are exposed to less than one microtesla – the unit used to measure magnetic fields – of EMF each day. Unshielded RFH systems can produce 20 to 40 times that amount. There’s only one unbiased third party that tests the EMF emissions of radiant floor heating systems: the Radiant Electric Emissions Test (REET). Many companies conduct their own tests and claim their products are safe, but only those that use the REET process can substantiate such claims.

Many companies test their RFH systems' EMF levels at a few points several feet above the flooring level, not where your feet actually touch. The REET procedure, however, tests 20 points at a height of just 0.5 inches (1.27 centimeters) above the mats themselves. When researching RFH systems, you may come across claims of 'zero EMF' or 'EMF free.' If EMF is a concern for you, look for systems that have undergone the REET test.

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