A cross section of an electric radiant floor heating system

Jorgen Jacobson | ©iStockphoto.com

Electric Radiant Floor Heating

Electric radiant floor heating (RFH) uses heat-conducting plastic mats containing coils warmed by electricity. So what are these heating coils? They aren't heated elements like you'd find in a space heater or on an electric stove. They're actually resistance wires, typically copper or nichrome, wrapped in a water-resistant polymer. Nichrome is an alloy of nickel and chromium with high electrical resistance -- ideal for producing heat. These wires are zigzagged through a mat and then wired for electricity. Think of a large, rolled-up electric blanket without the fabric and you'll get the picture.

On installation day, you or your contractor will roll out the mats and put the flooring material in place. Most people choose to go with electric RFH just for individual rooms since the cost of electricity makes this system quite expensive for heating an entire house. You can save money if your local power company charges less for off-peak usage. Cheaper nighttime power rates allow consumers to charge the heating elements overnight for less money -- then the heat is used over the course of the following day.

Electric RHF works best with floors made of ceramic tile, but it can be used with most types of flooring, including hardwood floors. Carpet is thicker and doesn't conduct heat as well as tile or hardwood flooring, but selecting the correct padding can greatly increase the amount of heat you'll get. There are two kinds of padding used on carpets -- slab and ribbed. Slab pads are flat and ribbed and have a waffle pattern. A 3/8 inch (.68 centimeter) slab foam rubber pad is recommended for RFH systems with carpeting.

Because an electric RFH system is usually used for single rooms, it's controlled either with a simple flick of a switch or automatically by thermostat. Since electric RFH system heating coils are installed between the subfloor and the floor covering itself, heating time is short. It typically takes about 30 minutes to an hour to heat your floor and room. Set the thermostat to turn up the heat an hour before you get out of bed, and warm, cozy bathroom tile will be ready to greet your bare feet.

For a small bathroom, you'll spend in the neighborhood of $400 to $800 to install an electric RFH system, and you can even do it yourself. It's no harder than laying tile, but you'll need a qualified electrician to wire the system to a thermostat. Unfortunately, there's no way to install the heating mats without first tearing up your existing floor, so the ideal time to make the switch to an electric RFH system in your bathroom, sunroom or kitchen would be during a renovation. Once the flooring is removed, just lay the mats and tile over them. The tile glue and grout won't affect the heating mats. Once the flooring is back in place, you can literally forget about the heating mats -- they require no regular maintenance.

When you factor in the cost of a radiant floor heating unit, keep in mind that electric systems rarely have problems. When they do, a homeowner can troubleshoot and make most repairs. Make sure to turn off the power before inspecting, repairing or replacing any panels.

Electric or hydronic, RFH offers a number of home heating options. To learn more about home heating and construction, please visit the links on the following page.