Can app-based communities support energy sufficiency in households? Evidence from a one-year quasi-experiment in Switzerland

App-based interventions are increasingly used to foster energy-sufficient household routines. Previous studies rarely measure whether the effect persists in the long-term, and for the few that have, the savings effects – often estimated without a control group – are not maintained over time. To favour long-lasting effects, we posit that (i) app users should be engaged in the app design, (ii) apps should focus on collective-level features that support community building (rather than individual-level consumption feedback only), and (iii) specific app features are needed in the long-term to resist relapse. We assess the overall effect of these strategies in the “Social Power Plus Community Energy Challenge”, an app-based intervention run in 2022 in Switzerland involving about 200 voluntary households. Quasi-experimental estimates under a weighted Difference-in-Differences approach show that on average the intervention produced nearly 5% energy savings over one full year. However, the effect was higher in the first quarter (up to 11% energy saving), becoming negligible in the last quarters. We reflect on how the three strategies did not ensure long-term effects and recommend future research to further explore the potential of community-based processes, focusing less on apps and more on collectively questioning dominant social norms around household routines.