Demonstration of Advanced High-Efficiency, Low-Capacity HVAC Systems

This project demonstrated the energy and comfort-related performance of high-efficiency, lowcapacity heating, ventilation, and air conditioning (HVAC) systems which replaced existing HVAC systems in five single-family homes located in Los Angeles and Orange County. The five test houses also received envelope upgrades, which included additional attic and duct insulation and air sealing.

The project team collected utility data from the test homes before and after the envelope retrofits and HVAC replacement. The team also performed building energy modeling to support the utility data analysis. The analysis and modeling results indicated that the envelope and HVAC upgrades can reduce the HVAC energy consumption by 30 percent or more in the demonstration homes.

The project team monitored the low-capacity HVAC systems over two winters and summers, tracking and analyzing comfort conditions within the houses and parameters like cycling, runtime, energy consumption and energy delivered. Occupant surveys concluded that all homeowners were more comfortable with the new HVAC system, indicating few or no comfortrelated issues and even providing better comfort.

Estimated ratepayer benefits from the envelope and HVAC upgrades include average annual savings of 880,786 therms of natural gas and 6.4 GWh of electricity, with associated annual cost savings of $1,300,709 for natural gas and $1,277,220 for electricity. The avoided cumulative carbon dioxide emissions in the next five years would be up to 33,910 metric tons, and NOx emissions avoided would be up to 12.1 metric tons.