Heat the Floor, Not the Ceiling
by Carol Lee
Brrrrrr. The last of the leaves have been raked. My woodpiles are stacked high and wide and are architecturally sound. The blue of the tarps covering the wood is the only color for miles around. Everything else looks cold and grey, but inside my house it's all cozy and warm, because I've got radiant floor heating.
The Romans were the first to use hydronic radiant systems: they heated their baths with hot water springs that circulated under marble floors. During the Dark Ages in Europe, castles were heated in a similar manner. Modern radiant floor heat is merely a more sophisticated version of the same kind of system.
Hydronic radiant floor systems use a boiler to heat, and an electric pump or circulator to distribute the warm water through the tubing that loops back and forth beneath the floor. That warmth is then conducted to the floor's surface where energy (heat) is broadcast into the room. Hydronic systems are closed loop: the same fluid is heated, circulated and as needed, reheated. The circulator is the same as in other hot water—or hydronic—heating systems. Such systems can be fueled by gas, oil, solar and even geothermal energy.
According to the US Department of Energy, radiant floor systems provide even heating throughout the whole floor, rather than in localized spots, as with traditional heating systems. "The house heats from the bottom up, warming the feet and body first. Studies have shown that in houses with traditional forced air systems, the hottest part of the room is the top three to five feet."
Radiant heating works by warming your body and other objects rather than just the room's air. To better understand, imagine yourself outside stacking wood in the shade on a chilly October day. You take a break in the sunlight to soak up some rays. The air temperature around you is the same as in the shade, but the warmth you feel is radiant heat from the sun.
The Department of Energy deems radiant heat quieter, cleaner and more efficient than forced-air heating systems, adding that it also eliminates the draft and dust problems associated with the latter. A conventional forced air system comprising a furnace and duct work costs about $7,500 for a 2,300 square foot home. A typical slant/fin radiator hydronic system would run about $10,000. A radiant hydronic floor heating system requires a boiler, circulators, advanced controls and a few thousand feet of tubing and costs closer to $16,000. (Costs for each system vary widely.) But because of its efficient heating, the fuel cost savings of radiant heat will offset the higher installation costs over the years. And it's more comfortable, too.
John Abularrage, of Advanced Radiant Design in Stone Ridge, NY is a recognized expert in the field. Certified by the Radiant Panel Association to design and install radiant systems, he is also a certified instructor for the Radiant Panel Association, offering classes for contractors, builders, architects and engineers. John proposes that with radiant heating you could save up to 40% in fuel costs over forced hot air systems. And the new technology and materials used in radiant floor heating have proven very effective since the 1970s and work well with the finest hardwood flooring and high ceilings.
"That's because the radiant heat stays near the floor and doesn't rise to the ceiling, like hot air does. Two-thirds to three-quarters of the radiant energy goes directly toward heating objects in the room. Conventional heat systems heat air to 120 or 140 degrees. Radiant heating keeps the floor under 80 degrees (easy on fine hardwoods). There's no buoyancy . . .the hot air doesn't rise" and settle on the ceiling.
To prove this, John uses an infrared thermometer to measure the temperature of various areas in each room. With conventional heating systems, the floor will be about 55 degrees, and the hottest air, about 95 degrees, will be up at the ceiling. With radiant heating, the floor surface will be between 75 degrees and 78 degrees, and all surfaces in the room will vary within less than one degree of one another. By contrast, the ceiling temperature will measure 62 degrees. "Radiant heat has a very low temperature distribution." Radiant floor heating is sufficient for 90% of all heating situations. In environments where there is excessive glass, however, an auxiliary heat source may be recommended.
Laurence Garrick, a building designer located In Rhinebeck, just added a large, double-height addition to his home in Rhinebeck, with many skylights, extensive north-facing glass exposures, and radiant floor heating. Because his ratio of glass to floor exceeded the load limit on the radiant system, he added auxiliary heating by looping a system of traditional 1950s-style radiators to his radiant heating. Both systems work on the one loop, and come on together (but the radiators heat up instantaneously.) "If an engineer had designed this room, it wouldn't look this way," he said, taking in the luxury and charm of the space.
Garrick, who designs and builds both stores and residences, says that radiant heat is a luxury. "The key word here is comfort. You can walk barefoot in winter! The part of the room that's usually coldest is now the warmest." He adds that a hydronic system with a boiler is more flexible for meeting the heating needs of a house because it can also make hot water for the house and even power an air handler to deliver hot or cold forced air through ducts (if added, for auxiliary heating or cooling. For more information, please consult the experts!)
William Levitt, who built thousands of mass-produced homes—one every few hours, actually—in Levittown, New York, was an early pioneer of radiant heating. However, Levitt's radiant system leaked after about 20 years because the copper pipes corroded over time due to their incompatability with the cement. This led to terrible messes and costly renovations. "Today's tubes will last the life of a home," says John Abularrage, who has been designing and installing radiant heating for 25 years. Radiant heating "doesn't cause problems because the tubing is encased in cement and is well-protected."
A local installer told me that if he won the lottery and could design any home, he would make sure to have radiant floor heating. His own 1,200-square-foot home with forced-air heating used 1,068 gallons of oil last year. My 2,300-square-foot home with radiant floor heating used only 913 gallons over the same year. (My husband designed our home as passive solar, with south- and west-facing glass exposures, and there's also the superior insulation factor of a newer home, that tips the fuel savings in my favor.)
It's freezing and winter is only just beginning. Snow will blanket the hillsides and storms will knock down tree limbs and power lines. But, honestly, who doesn't like Currier & Ives landscapes? Maybe I'll take up cross-country skiing. Or, I'll just turn up the heat, collect some wood, build a fire and watch the snow fall.
Resources
For more information call Laurence Garrick at 876-7060 or e-mail him at lga@hvc.rr.com.
Also check out the following websites:
