Smart thermostats, combined with multiple temperature sensors, and home energy management systems (HEMS) are experiencing rapid growth worldwide. Meanwhile, behavioral science-based programs, such as energy feedback and energy saving tips, have been also gaining attention. Can the two strategies work together and save even more energy? An experimental program was undertaken in Sapporo, Japan – a climate similar to Minnesota – to assess the joint impact of these two strategies.
One hundred households participated in the program. The first group received a tablet with an energy saving app and a HEMS control system, whereas the second group received only the tablet with the app. The app was designed to stimulate behavioral change through recommendations regarding indoor temperature and humidity settings. It also gave energy consumption feedback and energy saving tips (utilizing “nudges” such as social norms and prompts). The HEMS control system was designed to automatically control heating based on schedules configured in advance.
The impact of the different strategies was evaluated with a randomized control trial (RCT). Energy consumption data 1 year after the interventions indicates that the combined treatments yielded about 3.5% reduction compared to the control, while the app alone achieved about 2.4% reduction in winter. We also found out that the usage of the app differs between the two groups, suggesting that the app results in different levels of reduction with and without the combination of the HEMS control system.
- Do Smart Thermostats + Nudges Yield Greater Energy Savings?
- Sho Hirayama, Takahiro Tsurusaki, Mikiko Nakamura, Ruo Lin Yaw, Jun Kikuchi and Ayaka Tokuta
- 2018 Summer Study on Energy Efficiency in Buildings, August 2018