Energy education has been conducted to equip learners with relevant energy conservation knowledge for many years. However, learners seldom put the knowledge into practice and even have few ideas about how to reduce energy consumption. To this end, there is a need to address this issue to improve the efficiency of energy education. One of the strategies is digital game-based learning, which can enhance learning motivation and interaction with learners. In this vein, this study develops an Energy COnservation PET (ECOPET) system using a game-based learning strategy. With the use of a pet avatar, learners were encouraged to use home-energy conservatively in a playful and engaging way. The aim is not simply to teach learners how to reduce energy use, but to engage them in adopting appropriate energy conservation measures. An empirical study was conducted to examine if the ECOPET system could promote learners' understanding of energy conservation. The results demonstrated that the system significantly promoted learners' self-awareness, learning motivation, as well as willingness to conserve energy. (Contains 4 tables and 5 figures.)