Local organizations bring successful electrification to new and existing homes

Sep 14, 2023
Habitat for Humanity installation

In August 2022, Center for Energy and Environment (CEE) and the Minnesota ASHP Collaborative partnered with Twin Cities Habitat for Humanity (TCHFH) to increase the adoption of cold climate air source heat pumps (ASHPs) in new and existing homes. With the help of an EPA grant, the partnering organizations were able to demonstrate how air source heat pumps can pair with a gas furnace to improve energy efficiency. The goal is to accelerate decarbonization through the electrification of space heating.

Energy Analysis and Recommendations

Two homes were used to conduct research and identify findings. The first, still early in the design phase, was built to incorporate a dual fuel ASHP as the primary heating and cooling system. The second house, built in the 1960s, was undergoing a renovation project led by TCHFH. The home was retrofitted to incorporate an ASHP that could be paired with the existing gas furnace to reduce energy use. Through a series of energy assessments, CEE staff were able to make recommendations for improving the air sealing and insulation of each home to optimize for ASHPs. Both homes were then tested by CEE and deemed airtight, making them advantageous to use ASHPs as the primary heating and cooling source.

Testing & Results

To conclude the study, CEE conducted final testing by inspecting newly installed heat pumps to ensure proper system operation and collected data on additional energy upgrades for the final HERS rating. They confirmed HVAC upgrades, thermostat settings, and noted any other upgrades that could impact the HERS score. A TCHFH supervisor met with CEE staff onsite to discuss thermostat settings and equipment performance. In the end, the existing home achieved an estimated post-HERS score of 77, meeting TCHFH's goal of HERS 80 or below. The new home achieved an estimated post-HERS score of 16, meeting the requirements for Energy Star, Indoor airPLUS, and Zero Energy Ready Home certifications.


Related Links

Case Study: Retrofitting for Electrification

Case Study: Designing for Electrification