This project refined a new approach to using mini-split heat pumps in existing homes. The team focused on using a single, centrally located mini-split heat pump as the primary system, while only using the existing, lower-efficiency central system as needed. Previous research documented 34% average heating and cooling energy savings for Florida homes that utilize this novel approach.

The team also developed an integrated controller to better coordinate operation of the mini-split and the central system, enabling additional savings and improving comfort. Best-practice guidance for optimum design, installation, system control, and central system replacement at end-of-life was developed to foster mainstream adoption of the approach.

Over the course of this project, the team:

• Demonstrated persistence of cooling energy savings with a supplemental mini-split heat pump
• Demonstrated the ability to maintain comfort within Air Conditioning Contractors of America Manual Residential Systems guidelines
• Demonstrated the ability to enhance cooling energy savings and maintain comfort with set point optimization and periodic (nighttime) fan cycling
• Selected hardware and developed a software algorithm for Integrated Controller Design
• Conducted central system end-of-life simulations.

Read more about this success story on the project web page.