Home Touch

RADIATING WARMTH

A radiant heating system can take the chill off ceramic tile and the "brrrrrr" out of marble flooring.

Concrete, stone, tile and wood floors can be warmed by pipes that carry heated water or mats that conduct electricity, which are affixed to the subflooring. Rather than heating an area with conventional forced hot air, radiant floor-heating systems not only warm the surface on which people walk, but that heat is eventually absorbed and radiated a house's contents as well.

Prevalent in Europe, Americans are warming to the usage of radiant heating systems, says Mark Eatherton, executive director of the Radiant Professionals Alliance (RPA), based in Mokena, Illinois. "Radiant heat is an even heat, unlike a forced-air heating system, which can have pockets of warmed air," he says. "Technological advances and product innovations have stepped up interest in radiant heating."

Using radiant heat to create a warmer home isn't new. The ancient Romans built hypocausts, which were floors raised on tile piers that were heated from beneath. Used initially for bathhouses about 100 B.C., hypocausts were a common feature of stone houses in colder parts of the Roman Empire.

While today's radiant heating systems are much more sophisticated, they operate on the same physical principles of energy transference -- the movement of heat from warm objects to colder ones. The Radiant Professionals Alliance is a trade organization of 250 members that primarily works with hydronic (water) radiant floor-heating systems. Cross-linked polyethylene (PEX) tubing is a long-lasting, flexible pipe that carries heated water beneath the floor's surface and doesn't corrode.

A boiler system heats the water, which is pumped through tubes in a closed-loop hydronic radiant floor system. Eatherton says a hydronic radiant system is easier to install during new construction, as opposed to retrofitting a system into an existing home. "A hydronic radiant floor-heating system must be specially designed for each house, but minimally, you want at least one linear foot of tubing per square footage in the home," he says. "When compared to forced-air heating systems, energy cost savings with radiant heat can average between 15 percent to 50 percent, depending on a home's location and how well it is built and insulated."

A qualified plumber should be contracted to install a hydronic system with industry-estimated costs between $8 to $10 per square foot for new construction. Loops of PEX tubing can be embedded in a concrete basement or placed between the floor joists in upper floors. Above-ground applications using radiant floor heating should have double the amount of insulation in walls and attics to maximize the warming effect. When the system is first turned on, floors may take a day to warm up to 75 degrees, but, once warmed, the heat is easily maintained.

A detraction is that a radiant floor heating system might be considered a redundancy, since duct work for air conditioning is often standard in home construction. But, Eatherton says, industry manufacturers are working to perfect radiant cooling systems coupled with air circulation.

If a homeowner wants to take the chill off the floor in a small area, an electric heated-floor system under stone or tile can be a creature comfort and is a preferable retrofit in an existing home. Electric mats or rolls are constructed of coils of heat resistance wires that are joined to a supporting material. These heating mats are designed to operate like an electric blanket under the floor. Bathroom floors can achieve a comfortable temperature in less than an hour and can be controlled by a programmable thermostat.

STEP Warmfloor is an innovative hybrid of an electric floor-warming system designed to heat an entire house. Manufactured by Electro Plastics Inc. near St. Louis, the product is a low-voltage polymer radiant heating system, which has thin wires that warm plastic, then radiates the heat at a temperature that is self-regulating.

"STEP Warmfloor's system cannot overheat because the black carbons in the plastic are semi-conductive to a maximum temperature of 85 degrees," says Monica Irgens, president of the company. "Our product runs on AC, using a 24-volt transformer, or DC current, such as a solar- or wind-powered source."

An electrician should connect the system to the power source, and Irgens estimates the installation of STEP Warmfloor to cost between $11 and $15 per square foot.

Radiant heating systems are heating up outside homes, too. Called "snowmelt" systems, these radiant heat assemblies are embedded under sidewalks and driveways. These systems work by heating snow-covered surfaces to 38-degrees, at which temperature, the precipitation evaporates.

A radiant heating system is an effective way to clear a snow-covered pathway without tearing up decorative concrete, stone or brick. Snowmelt systems can be both electrical or hydronic, with anti-freeze added to circulating water. Irgens says the STEP Warmfloor product can also be installed under rooftops, to prevent ice dams from forming near roof overhangs and gutters.

Educated consumers are turning up the heat on radiant heating systems, not only because of long-term energy savings, but because of the warmth they provide. "Radiant heat is like a blanket of comfort inside the home that you can only experience," Eatherton says. "When you step inside a home that has radiant heat, your body immediately senses a total, encompassing warmth."

Warm Up

-- STEP Warmfloor, Warmfloor.com, 877-783-7832 or 877-STEPTEC

-- Radiant Professionals Alliance, RadiantProfessionalsAlliance.org, 877-427-6601

(For editorial questions, please contact Universal Uclick at -uueditorial@amuniversal.com)

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