Promoting environmental awareness and sustainable behavior is an important action for climate protection. In this paper, we introduce a gamified eco-feedback approach using an interactive plant-like physical interface to encourage lower heating energy consumption in households. The interface is designed to be a part of the user's environment and evoke a caretaker relationship. It measures indoor climate parameters via sensors, awards users with points for environmentally friendly and healthy heating and ventilation habits, and changes its shape to mimic growing and flourishing. Through their mobile device, the users can retrieve detailed information in a companion app. A prototype implementation demonstrates the feasibility of the concept and serves as a basis for further work in this emerging research area.