The purpose of the study was to understand the effect of smart thermostats in residential homes within specific PG&E climate zones. The two focus areas were:
- An estimation of the energy savings
- An assessment of the participants’ experience
Three different brands of thermostats were tested with the goal to install 1,000 units of each brand. A total of 2,207 thermostats were installed.
The study used a randomized encouragement design (RED) in which several thousand homes were randomly assigned to the encouraged group and offered a free, directly installed smart thermostat. Two thousand similar homes were randomly assigned to a control group.
Monitoring occurred over two winter heating and two summer cooling seasons from late 2015 through the summer of 2017.
Overview of Analysis
The impact analysis leveraged a regression-based approach to estimate monthly and annual electricity and natural gas savings from participants with smart thermostats in the encouraged group.
The Participant experience analysis employed web-based surveys over the course of the study to understand experience, satisfaction, and energy efficiency attitudes among participants. The study also surveyed control customers for comparison. The bar graph shows percent of participants using green features.
Key Results & Applications
The study resulted in the acceptance of the Smart Thermostat measure as a deemed savings estimate in the California TRM.
Year 2 Annual Impact Results: Electric
View the full report: Smart Thermostat Study | ETCC (etcc-ca.com)