A Yardstick Consumers Use to Measure Home Energy Performance

D. A. Hoffmeyer, U.S. Environmental Protection Agency

Keywords

Abstract

ENERGY STAR has developed a software application, the Home Energy Yardstick (www.energystar.gov/yardstick), that compares the annual energy use of a home to the energy use of other homes nationally using data from the 1997 Residential Energy Consumption Survey (RECS). The comparison is made through a simple metric that ranks a home on a 0 to 10 scale after adjusting for home size and age, occupant number, climate, and whether a home has a well pump. This adjustment allows the tool to compare energy use across homes with different climates, size, age and number of occupants, and compensates for homes with well pumps. The adjustment is based on a regression model developed from analysis of RECS. These factors, which are considered beyond the control of the homeowner in the short-term, accounted for 20 - 30% of energy use variability, based on model R-square. Once energy use is adjusted, the application compares the adjusted energy use to the energy use of other homes within the RECS database and assigns a performance ranking. The performance ranking depends on the building envelope, the heating and cooling system, and the homeowner’s appliances (i.e. pool/spa), lighting and consumer electronics. Homeowner behavior is also important. This paper will describe the development of the adjustment procedure, and the results from testing the application using actual home energy data from the RECS 1993 database. In addition, a brief discussion of the potential applications and implications of this new metric for measuring home energy performance is included.