Air-to-Water Heat Pumps

Josh Quinnell, Ph.D.

A possible cold climate solution for high-efficiency cooling, space heating, and water heating.

Air source heat pumps (ASHPs) have captured attention lately as a potential pathway for both energy efficiency and decarbonization. A lesser known subset of ASHP equipment, the air-to-water heat pump (AWHP), promises similar high efficiency for hydronic distribution (i.e., boiler) systems. AWHPs have the flexibility to interface with radiant systems, forced-air systems, and even domestic hot water. As such they have the potential to bring heat pump technology to even more end-use applications.

This project is a field study of AWHPs to characterize and evaluate their efficiency, performance, and cost-effectiveness. AWHP systems will be installed in representative scenarios. The systems will be fully instrumented and monitored for two years to measure and demonstrate their performance in cold-climate applications. This project will validate the potential of this technology to bring significant efficiency to residential electric heating, which is used in 17% of the homes served by Minnesota’s cooperative and municipal utilities.

This project is supported by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD) program, which is funded by Minnesota ratepayers.  

Project Info


Conservation Applied Research and Development (CARD) grant program

This project will assess the energy savings and cost-effectiveness of air-to-water heat pumps for heating, cooling, and domestic hot water, as well as inform utilities and consumers about which system types and configurations are best suited for Minnesota homes. 


  • Market and technology assessment
  • Site recruitment and installation
  • Monitoring and experimentation
  • Analysis
  • Dissemination of findings

Non-energy benefits

  • Decreased costs of ownership
  • Lower utility bills
  • More easily serviceable systems  

Josh Quinnell