Discovering Air-to-Water Heat Pumps

Josh Quinell, PhD
airtowater heat pump

The cold climate solution for high-efficiency cooling, space heating, and water heating?


Recent work with heat pump technology has yielded options that are high in efficiency, but also high in cost, like ground source heat pumps (GSHPs), which require a geothermal well. An alternative heat pump technology — the air-to-water heat pump (AWHP), a new variant of an air source heat pump (ASHP) — uses electricity to move heat from outdoor air into indoor water. These systems are compatible with radiant heating, domestic hot water, and forced-air distribution. They offer the potential flexibility and higher efficiency of GSHPs at lower costs that are comparable to air source heat pumps. 

This project is a field study of AWHPs to characterize and evaluate their efficiency, performance, and cost-effectiveness. AWHP systems have the potential to play a central role in the future of residential electric heating, which is used in 17% of the homes served by Minnesota’s cooperative and municipal utilities. Field-monitored units are essential to demonstrate their promise in cold-climate applications.

Project Summary


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.


  • Task 1: Market and technology assessment
  • Task 2: Site recruitment and installation
  • Task 3: Monitoring and experimentation
  • Task 4: Analysis Task 5: Dissemination of findings

Non-energy benefits

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