Eco-feedback has been proved effective in promoting energy-saving behaviors in residential contexts. However, in terms of thermostat settings in the workplace, its effectiveness may be reduced by thermostat-setting habits and low motivation to save energy. To solve these problems, this study proposed and compared two types of interactive feedback integrated with thermostat interfaces: feedback of energy efficiency, and feedback of health level of the current temperature setting. Experiments with simulated thermostat interfaces on 84 office workers in a controlled thermal environment showed that both types of interactive feedback resulted in higher temperature setting and preference than interfaces without feedback. Self-reported data revealed the mechanism of the change: feedback not only transformed users' decision-making style from a habit-driven mode to a deliberate thinking mode, but also induced more positive attitudes towards higher temperatures in setting thermostats. The attitude change was caused by changes in both the belief about importance of related attributes (e.g. comfort not being so important), and in the ratings of temperatures on these attributes (e.g. 27 degrees C being a comfortable temperature). While the two types of feedback did not differ significantly in terms of temperature setting, preference, and attitude change, they acted on different factors underlying thermostat-setting process. These findings demonstrate the power of interactive feedback in promoting energy saving in setting thermostat, and the possibility to save energy with feedback content appears unrelated to energy saving. (C) 2018 Elsevier B.V. All rights reserved.