My Buddy the Backup Boiler: Dual-Fuel and All-Electric Air-to-Water Heat Pump Installations in Wisconsin

Domestic hot water, space heating, and space cooling account for most residential energy use, making these systems key targets for efficiency improvements. Air-to-water heat pumps (AWHPs) offer flexible and efficient pathways to install or retrofit radiant heating systems. This FOCUS ON ENERGY® 2025-2026 field study evaluates the performance of five AWHP systems across four residential buildings in Wisconsin.

This paper was presented at the 2026 ACEEE Summer Study on Energy Efficiency in Buildings.