A radiant heating system uses electric cables or small tubes of hot water embedded in a concrete floor, under a tiled floor or attached to the underside of the subfloor.

Instead of heating air and circulating it throughout the house, radiant heat warms objects - carpet, furniture and even people. Less energy is needed to transfer heat directly to people, rather than fill the entire room with heated air like a forced-air furnace.

Types of radiant heating

Hydronic systems are the most popular and cost-effective. Hot water is pumped from a boiler through polyethylene tubing underneath the floor. The temperature in each room is controlled by regulating the flow of hot water through each loop of tubing, using a series of thermostats and zoning valves.

Electric heating cables can be embedded in a poured-concrete floor, or in the mastic under tiled floors. Some manufacturers offer the product in a portable mat that can be spread under wall-to-wall carpet - a great option for apartment or condo dwellers.

Floor coverings and radiant heat

Ceramic tile is usually the floor covering of choice for radiant heating, but almost any material can be used, depending on how the system is installed.

Solid wood flooring can be used, but many manufacturers recommend using laminated wood products instead. This reduces the possibility of warping and cracking from the drying effects of the heat.

Carpeting can be used, but keep in mind that it will slow the flow of heat into the room. Use a thin carpet with a little padding as possible.

The benefits

Homeowners with radiant floor systems claim it's the most comfortable heating option. Heat is produced evenly across the entire room, eliminating hot and cold spots common with forced-air systems. Radiant heat also warms from the bottom up - when your feet are warm, the rest of your body feels warm too.

Radiant systems are also very quiet, with no noisy blower fans or clunky radiators, and they don't circulate dust and allergens like forced-air systems. During the winter, the humidity remains at a more comfortable level.

And best of all, radiant heating systems are energy-efficient - you can set the thermostat of a radiant floor heater six to eight degrees lower than usual and have the same level of comfort. Energy savings of 15 to 20 percent are common.

The drawbacks

Because radiant heating systems are self-contained, a completely separate central air conditioning system must be installed, including ductwork.

Price is also a factor - the cost of a whole-house installation can be 40 to 50 percent more than a conventional heating system.

For those reasons, most Midwestern homeowners use radiant floor heating to supplement their standard furnace. It's great for warming cold bathroom floors, or heating a new addition without expanding the existing furnace and ductwork.