Air-to-Water HEAT
Your house not a good fit for an air-to-air heat-pump system? Consider an air-to-water heat pump to supplement the heat, supply hot water in summer, and bring air conditioning to your home.
Air-to-water heat pumps work similarly to air-to-air heat pumps, except that the low-temperature heat extracted from the outdoor air is used to heat water inside a hydronic condenser before delivering it indoors. These are an ideal retrofit for any hydronic HVAC system designed for low water temperatures, such as newer hydronic baseboard or in-floor radiant systems. But they are not a seamless retrofit for older high-temperature boilers, says Jim Bashford, national sales and training manager for SpacePak, which has offered Solstice air-to-water systems since 2011.
That said, air-to-water heat pumps can make a significant difference in both comfort and cost as a supplement to existing heating systems, while adding all-important air conditioning in the summer months. (They can also supply hot water during the warm season.) In shoulder seasons, a heat pump allows you to turn an older forced-air or hot-water boiler down, from, say, 140 to 120 degrees. That way, the boiler doesn’t kick on when the temp drops below 60°—the heat pump does. The difference can be significant in areas where fuel oil or propane heating bills run $500 to $1,000 per month. “If I only have to run my expensive heating source six weeks out of the year, instead of four months,” Bashford says, “that’s a considerable savings.” He recently installed an air-to-water system to supplement a propane heater in his home in New York’s Hudson Valley. His propane use dropped by four-fifths, saving him several hundred dollars per month. His electric bill increased by only about $20 per month.