Impacts of home energy management systems on electricity consumption

•Real-life consumption data was gathered in 10 households before and after the installation of the HEMS.•Energy conservation increased and the daily consumption profile changed.•HEMS brings savings up to 30% if householders value energy conservation over comfort.•Even families, who value comfort above other values, gained savings.•The level of energy conservation varies greatly in each household and between them. Home energy management systems (HEMS) connect homes to a smart grid and may increase the overall use of renewable energy by directing energy demand to off-peak hours and increasing energy conservation. However, the promised changes in electricity consumption have yet to be proven in real-life experiments. We therefore analysed the changes in electricity consumption, daily consumption profiles, and number of low and high consumption hours after installing HEMS in 10 Finnish households. These changes were examined in the context of the values related to energy use in each household, which were derived from semi-structured interviews. In the real-life experiment, we showed that the HEMS reduced the total consumption of electricity in the winter months by up to 30%, shifted the consumption to off-peak hours and decreased the number of high consumption hours. These changes occurred even in the homes that valued comfort over savings or ecological sustainability. Nevertheless, the levels of energy conservation varied greatly between the households and between months in the same homes.