Heating load estimates and duct performance diagnostics for successful ASHP retrofit installations
Researchers
Term
2026–2028
Overview
Retrofit air source heat pumps (ASHPs) and duct systems must be properly sized to reduce energy costs and carbon emissions. This project will conduct load calculations and duct performance measurements in out-state 1–4 unit residences, complementing the results of a current Twin Cities study. The results will inform recommendations for load-estimating methods for homeowners, auditors, and contractors. They will also determine how often existing ducts can accommodate larger-capacity ASHPs with or without weatherization and duct improvements.
Highlights
Objective
- Document and discuss the accuracy and trade-offs of current methods and recommend data-backed heating load estimation methods for homeowners, auditors, and contractors.
- Analyze existing duct systems to determine if they can accommodate ASHPs sized for the design heating load.
- In cases where existing duct systems can’t support an ASHP sized for the design heating load, determine whether envelope and duct improvements can be used to meet ASHP sizing requirements.
Scope
- Conduct Manual J heating load estimates and duct system performance measurements for a segmented sample of 60 out-state Minnesota homes.
- Compare the results of the out-state houses to those of homes in the Twin Cities metro area.
Non-energy benefits
- Facilitate the reduction or elimination of fossil fuel use in a home’s energy supply.
- Reduce local pollutants from combustion by advancing home electrification.
Funding
This project was supported in whole by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD) program.