Measured public benefits from energy efficient homes

The objective of this paper is to summarize results of two studies that compared Baseline, ENERGY STAR® and Guaranteed Performance homes co-located in Phoenix, Arizona, USA and determine if homes in these three groups could be distinguished from each other in terms of actual summer/cooling energy usage or homeowner satisfaction related to the HVAC systems. The summer/cooling energy use study surveyed 7,141 houses, of which 3,336 were Baseline homes, 2,979 were ENERGY STAR homes and 826 were Guaranteed Performance homes. Statistically valid energy data shows that ENERGY STAR homes saved on average 16% in summer/cooling energy use (kWh/m²) as compared to the typical Baseline homes. The Guaranteed Performance homes saved on average 33% in summer/cooling energy use over the Baseline homes and saved 20% compared to ENERGY STAR homes. During the spring and summer of 2005, the homeowner satisfaction study was administered to 708 houses from the same 7,141 house sample set. The second study found that 49% of the Guaranteed Performance homeowners said they were completely satisfied with their home’s "ability to keep them comfortable year round" compared to 35% of ENERGY STAR homeowners and only 27% of Baseline homeowners. In fact, this survey found that Guaranteed Performance homeowners were more satisfied with every aspect of their home’s HVAC performance ― year round comfort, the freshness of air inside the house, evenness of temperatures from room to room, reliability and cooling cost compared to Baseline and ENERGY STAR houses. Combining the results from these two studies shows that Guaranteed Performance homes consume less energy than comparable ENERGY STAR or code-built homes while simultaneously improving homeowner satisfaction.