Air-to-water heat pumps work similarly to other air-source heat pumps except that they use water, instead of air, in the distribution system. This means that instead of blowing hot air in the winter to provide heat, air-to-water heat pumps circulate hot water in a radiator or in baseboards to provide heat to a home.
As compared to air-source heat pumps, air-to-water heat pumps require less interior refrigerant piping. Similar to boiler-based systems, heat is delivered by the circulation of hot water to radiators or baseboards; however, because the hot water is delivered at a lower temperature than from a boiler, existing radiators and baseboards may need to be upgraded to a compatible style.
Unlike typical air-source heat pumps, air-to-water heat pumps have the potential to heat domestic hot water, and they can provide cooling if they are connected to a cooling system that can use chilled water, like a hydronic fan coil.
Air-to-water heat pumps are not widely available in the United States at this time, but there is growing interest in the technology.
