As the use phase of buildings produces a substantial negative environmental impact, mechanisms to guide individuals towards more sustainable energy consumption are of interest. Smart energy apps which constantly monitor energy consumption and provide energy reduction recommendations to private households are a promising tool to tackle this issue. However, as little is known about factors driving their adoption, it remains unclear whether their potential can be leveraged. Against this backdrop, this study derives a technology acceptance model for smart energy apps which builds on a quantitative survey with 300 participants and the partial least squares approach. The results highlight personal innovativeness and environmental norms as additional acceptance factors. Our study points at the importance of personality traits and individual beliefs in technology adoption research, unveils potential levers for IS to drive adoption, and provides guidance to smart energy app designers.