Smart thermostats allow continuous learning, remote scheduling and control of indoor temperature. This paper empirically evaluates indoor environmental conditions, occupant experiences and prevalence of summertime overheating in three low energy dwellings with smart thermostats and compares the results with three similar dwellings with standard programmable thermostats. The study uses building performance evaluation methods combining time-series data on temperature, relative humidity, and window opening with survey data on occupant perception of thermal comfort and heating control over the period 2019 - 2020. While there was little difference observed in the measured and perceived indoor temperatures between dwellings with and without smart thermostats, the six dwellings were different in the way they heated their homes and controlled their indoor environment. A wide indoor temperature range of 16oC-22oC was observed in dwellings with smart thermostats during the heating season. Majority of dwellings also experienced summertime overheating with temperatures in bedrooms going up to 34oC. Individual heating preferences dominated the use of smart or standard thermostats ranging from Cool Conserver, On-off Switcher to On-demand Sizzler. It is vital that energy models consider a range of heating preferences to avoid a gap between expectation and reality.
Gupta, Rajat Gregg, Matthew
School of Architecture
Year of publication: 2022Date of RADAR deposit: 2022-02-01