Ask an HVAC pro about radiant floor heating, and he’s likely to tick off a few of the benefits: It’s efficient because it eliminates duct losses, it won’t stir up allergens as a forced-air system does, and many homeowners prefer the comfort of warm floors.
Ask that pro about radiant cooling, however, and you’re likely to get a furrowed brow and a quizzical glance.
So when Connecticut custom builder Steve Zarrella constructed a five-bedroom home designed for year-round comfort with radiant heating and cooling, he was going where few American builders had gone before.
Zarrella worked with New Canaan, Connecticut–based HVAC contractor EU Systems to design and install the system with ceiling panels from Italian manufacturer Messana. In the winter, the panels circulate warm water at about 85 to 120 degrees Fahrenheit, radiating heat downward. In the summertime, the system simply switches to chilled water, eliminating the need for ductwork carrying air-conditioned cool air.
The 6,000-square-foot, shingle-style home in New Canaan, Connecticut, is one of the first in the Northeast to use ceiling panels for radiant heating and cooling.
The 6,000-square-foot home in New Canaan was initially slated to use a traditional forced-air system, but Zarrella convinced the homeowners to let him try out the unfamiliar technology to improve the home’s comfort. “I have to admit we were biting our fingernails too in the first cooling season, because we didn’t know how comfortable it was going to be,” Zarrella says.
After three heating seasons and two cooling seasons, the results are in. “It was fabulous,” Zarrella says. “It is by far, to date, the best mechanical system we’ve ever installed.” Along with happy clients, Zarrella’s firm, Construction Management Group, earned two HOBI awards for Best in Town Custom Home and Best New Construction Technology from the Home Builders & Remodelers Association of Connecticut.
Radiant heating with propane backup
With temperatures that can swing from well below freezing in the winter to the sweltering mid-90s in the summer, Connecticut provides a particularly rigorous trial for a system that had only been proven in Europe and a few California installations. With the help of a high-efficiency propane boiler, the system lived up to the year-round comfort test.
A 5-ton/60,000–British thermal unit (Btu) heat pump provides the system’s primary stage of heat. A control system monitors the home’s heating demand, and when the heat pump can’t bring the buffer tank to its target temperature (generally when the outdoor temperature drops below 25 degrees), the wall-hung propane boiler takes over. The propane boiler is a necessary backup in this climate zone for all but the most highly insulated homes because it can produce water at a much higher temperature than the heat pump, Zarrella says. It also provides the home’s domestic hot water through an indirect tank.
“It is by far, to date, the best mechanical system we’ve ever installed.”
The sophisticated control system uses 21 thermostats throughout the house to monitor both temperature and humidity and maintain indoor comfort within a ½ degree of set point. A heat recovery ventilator with dehumidifier maintains the home’s humidity during the summer to ward off condensation. “It’s incredible comfort,” Zarrella says. “There is no room or area that has experienced stratification. It is wonderful not to have to blow dust around the house with a forced-air system. It’s very quiet — you don’t hear the system at all.” And since the system replaces ductwork with prefabricated gypsum panels, the installation saves time and ceiling space.
Standby power keeps the heat on
The shingle-style home is located on a cul de sac in a desirable part of New Canaan with fantastic school districts, Zarrella says. While the home is located close to town, most of New Canaan doesn’t have access to natural gas. But with propane, the homeowners were still able to fuel their innovative heating system, along with a propane range and oven, an outdoor grill, a propane fireplace, and three log lighters.
A 22-kW, propane-fueled standby generator is also critical to maintaining the home’s comfort in the event of a power outage. During an outage, the heating system switches to the propane boiler due to its much smaller electrical demands, and the generator keeps the pumps circulating warm water through the home. The home’s general lighting, appliances, and other critical loads are also protected.
“We suffered some shocks in our area,” Zarrella says. “The longest power outage in our area was about a week, even 10 days in remote areas.” After a recent hurricane, he adds, the demand for standby generators soared throughout the region.
While the home’s radiant heating and cooling system was unique when Zarrella first installed it, he says the system has become increasingly popular on the west coast, and he’s embarking on another installation in a 12,000-square-foot home in New Canaan. With a proven installation that stands up to both cold and hot temperature extremes, future Northeast installations are likely to be an easier sell.