Abstract Global warming has been raised as a key issue recently. The carbon emission is considerably affected by the energy consumption of daily life among plenty of causes, and the need of changing people's behavior formed a consensus for reducing the energy consumption. Because people's lifestyle can be affected by those who create the built environment to a great extent, designers’ awareness about sustainable lifestyle facilitates people's behavior change into sustainable one. The basic assumption is that, if some information insinuating eco-friendly design is provided in an ambient way to the designers during the design education, the awareness about sustainable design can be significantly improved. In this paper, we identify the effects on the design process when the eco-friendly design information is provided to students together with visual information of comparative evaluation. A game theory-based scenario was utilized to stimulate the competitive design activities among students. We propose a design education assistance system that reflects the outcomes of the experiment. In conclusion, providing the competitive evaluation comparison with ambient information about sustainable design helps develop the design awareness on sustainability with better outputs.