Air-to-water heat pumps and water-to-water geothermal heat pumps provide warm water for space heating, domestic water heating, and chilled water for cooling. Switching a hydronic heat pump system from space heating to cooling and vice versa seasonally is relatively simple. The system operating mode is changed at the thermostat or a dedicated system mode switch with heat, off, and cool settings.
I attended a conference hosted by the Building Performance Association and presented on air-to-water heat pump systems. Many professionals were interested in heat pumps, especially ductless air-to-air systems. One person mentioned the difficulty of finding qualified installers for air-to-water heat pumps and noted the higher cost compared to ductless air-to-air systems.
Last month, we discussed how solid thermal energy storage, combined with an air-to-water heat pump and an electric boiler, provides a platform to leverage time-of-use electrical rates in ways that can benefit customers as well as the utility providing the electricity.
The Ambient Air-to-Water Hydronic Heat Pump features a 5-ton capacity (rated at 60 MBH) and provides reliable space heating with outdoor temperatures as low as -13° F.
There is a growing interest in adding air-to-water heat pumps to existing hydronic heating systems. While I support their use, I do not recommend replacing a perfectly good cast-iron boiler that still has a long service life.
By combining water heating with space heating through heat pumps, a synergy is achieved that maximizes efficiency. This dual functionality is particularly relevant given the constant demand for hot water in residential, commercial and industrial settings.
Hydronic-based heating and cooling systems stand ready to offer plenty of design and performance benefits. One of them is the potential for thermal storage.