An air-to-water heat pump (AWHP) is an electric heating system that pulls heat from the outside air and transfers it to water pipes delivering heat to radiators and in-floor radiant systems, doing the work a boiler or geothermal system would normally do. They can operate at up to 500% efficiency and can work in tandem with a backup boiler, saving substantial amounts of energy and potentially reducing energy costs. Air-to-water heat pump systems have been used in Europe for years and are already gaining traction in the Northeast.

Project Timeline: October 2023 - June 2026
Customer Segment: Single-family Residential, Multifamily Residential

Demonstration Project Objectives:

• Demonstrate the impacts of AWHPs in three single family buildings and one multifamily building in Wisconsin including both retrofit and new construction applications. This will include a combination of combined domestic hot water and space heating, cooling, and load shifting using a storage tank and controller.
• Define key characteristics (i.e., climate zones, age, fuel type, level of weatherization, hydronic distribution emitter type, and size) that make a home a promising candidate for an AWHP and identify high-opportunity archetypes for AWHP.
• Identify the installation barriers for AWHP in Wisconsin, including potential supply chain issues.
• Understand the comfort impacts of AWHP as retrofits to existing hydronic heating systems including whether the systems can provide both sufficient heat and hot water.
• Document the electricity consumption, backup fuel consumption, and system efficiencies of AWHP. Analyze the impacts to these factors as compared to baseline space heating sources.
• Investigate the load shifting potential of smart AWHP systems with storage tanks.
• Meter performance before and after installation and model the operations of the proposed AWHP using building energy modelling software to estimate the expected savings from the installation.
• Document system failures, changes to operating parameters, and adjustments required throughout the monitoring of the system.
• Quantify costs associated with AWHP systems and retrofits, including product, installation, and operating and maintenance costs.
• Understand the perspective of the following stakeholders through surveying:
  • Users: ability of the equipment to meet user needs and provide a good customer experience.
  • Installers: installation lessons learned, technology limitations, and training needs.
  • Builders: installation lessons learned, sales pitch for technology to buyers.
  • Determine any field limitations and opportunities of the technology.
  • Draft a TRM workpaper to support eligibility of AWHP as a prescriptive measure within the Focus on Energy portfolio.