Smartphone-enabled real-time data on home electricity use and indoor air quality to promote energy-saving behaviors

Occupant behaviour is recognized as a key factor in influencing energy efficiency in residential buildings. Research has shown that feedback programs are effective in motivating consumers to take proactive steps toward improving energy efficiency. However, there remains a need for empirical evidence on how real-time feedback on both energy consumption and non-energy indicators, such as indoor air quality (IAQ), can effectively motivate behavioural change and be integrated into energy efficiency policies. This study aimed to conduct a cross-over randomized controlled trial (RCT) to assess the potential of using real-time data on home electricity consumption and IAQ via a smartphone app to encourage households to make more informed decisions and reduce energy use. A total of 101 Portuguese families with children participated, with IoT systems installed in their homes to track daily electricity consumption and IAQ. Three sequential nudging interventions were delivered through the app, providing real-time data on energy consumption and IAQ, in some cases along with push notifications. Results revealed that the number of household occupants (p = 0.002), the existence of north-facing glazed façades (p = 0.017) and the use of electricity for heating (p = 0.034) were significant factors influencing electricity consumption, in a model explaining 34.9 % of the variance. The study also highlighted that families in homes built before 1980 are exposed to higher risk of increased electricity consumption and compromised thermal comfort, suggesting that retrofitting older buildings to address inefficiencies should be a priority. Whereas nudging interventions did not lead to a significant reduction in energy consumption, they did increase participants’ intention and motivation to save energy. Additionally, IAQ was found to play a role in fostering energy-conserving behaviours. Future research should investigate the long-term impact of combining nudging with strategies such as financial incentives and building upgrades to develop a comprehensive and sustainable approach for improving energy efficiency and well-being in residential buildings.