Optimized Installations of Air Source Heat Pumps for Single-Family Homes

Update: February 2024

The project is nearing its conclusion with findings on the importance of quality ASHP installation and design. There are so many possible configurations that it is vital to map and match heat pump solutions onto existing heating system conditions for cost-effective and energy efficient results. This represents a departure from how HVAC systems are typically updated, therefore will require sufficient contractor education and training. Many design questions are around zoning and control, with the goal of marrying the best performance and cost with how the unit is serving the consumer. CEE research staff presented a CARD webinar this winter on the single-family project.

Update: November 2023

The project team is finalizing their analysis and moving into the reporting phase. Preliminary results indicate several best practice approaches that optimize integrating ASHPs into existing heating systems to maximize savings and energy efficiency. A blanket approach to installation can result in inefficient use of the system or fewer cost and comfort benefits for occupants. The team wants to build off this project with more connected diagnostics that would automate quality control based on the specific configuration of a user's heating and cooling system. This would also streamline and simplify best practice application for contractors. A winter webinar for this project is linked at page bottom and a final report will be published soon.

Update: January 2023

The project team has completed installation of ccASHPs at almost all test sites and collected data through a partial heating season. From the initial results, the team concluded that the ccASHPs could have operated more efficiently and they are in the process of further optimizing installations and collecting and processing data on those updates. Project timelines have been extended and the team expects to summarize the test site data for a final presentation and report in 2023.

Update: October 2022

The project team developed the preliminary installation protocols and applied these to seven field installations. The team is studying how backup systems can be best integrated with mini-split systems since the two systems operate on their own individual controllers. As they enter the final round of data collection through the upcoming heating season, they will apply third-party controls to optimize integration of the mini-split and backup systems.

Update: April 2022

After surveying 25 electrically heated, single-family homes across Minnesota, the project team selected seven sites for ccASHP installation. The project team developed preliminary installation protocols and applied these to the seven field installations. The team is now monitoring performance at these field sites to gauge their success and modify the protocols based on those findings. An initial short summary and market survey were submitted to Minnesota’s Department of Commerce, Division of Energy Resources. 

Overview

The 2018 CARD Minnesota Energy Efficiency Potential Study identified cold climate air source heat pumps (ccASHPs) as the technology expected to provide 25% of total residential electrical savings in the state in the coming decade. This will be an essential component in meeting Minnesota’s 1.5% conservation goal.

Within the past year several Minnesota electric utilities have modified their existing heat pump programs or undertaken ccASHP pilots to increase installations. However, installations have been slow to date, due to lack of familiarity and clear guidance on installation and operation in cold climate applications for this technology on the part of Minnesota contractors and consumers.

This project will install a sample of ccASHP systems in homes that are currently electrically heated. It will develop interim protocols for quality installation (QI) based on CEE’s knowledge of heat pump performance in cold climates, existing best practices guides, and information developed by this project on Minnesota’s electrically heated homes.

The QI protocols will then be implemented, tested, refined, and validated. It will collect and analyze field data to assess performance and customer acceptance, and to provide government energy agencies and utilities with evidence of reliable real-world savings from ccASHPs that have been implemented according to best practices for QI. Interim QI protocols and Minnesota Technical Reference Manual calculations will provide early results to help close the gaps that currently hinder market transformation. Then the field study will enable the interim protocols and calculations to be tested, refined, and validated in an array of homes, ensuring that the thousands of ccASHP installations anticipated through conservation improvement programs over the next decade are fully optimized.