In 2024, the North American air-to-water heat pump market saw significant expansion, with nine new offerings introduced at the January AHR show by companies new to this category. By year's end, at least 18 companies either have or plan to offer these pumps in the U.S. Read the list of these companies as of mid-2024.

Air-to-water heat pumps are becoming popular in the hydronic heating industry due to their energy efficiency and sustainability. Chris Decato of U.S. Boiler Co. notes a rising demand driven by their cost-effectiveness and reduced carbon footprint.

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.

Find out about piping options for retrofitting an air-to-water heat pump into an existing hydronic system.

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.

Electro Industries is a manufacturer of electric boilers, air-to-water heat pump technology, electric duct heaters and controls.