Monitored indoor temperatures and reported thermostat settings: How different are they?

We examined differences in reported winter thermostat settings and monitored temperatures for households participating in Bonneville Power Administration's Residential Standards Demonstration Program (RSDP) in the Pacific Northwest. The reported thermostat settings were obtained from a survey of RSDP participants, and indoor temperatures were read from special recorders inside the house. We found reported thermostat settings to be on the average 2 °F cooler than actual temperatures; differences between settings and temperatures were less for very energy-efficient homes than for homes built to current practice. We also contrasted households with small differences (±2 °F) between reported winter thermostat settings and monitored temperatures with those with substantial differences (5 °F or more). We were able to identify households with substantial differences based upon their space-heating electricity use, the winter outdoor temperature, the physical/structural characteristics of the house, the number of appliances, the socioeconomic characteristics of the occupants, the energy behavior of the occupants, and/or energy-related attitudes. Using discriminant analysis, we were able to classify 100% of the high-difference and low-difference groups correctly, using these variables.