Recently, the window-to-wall ratio in the building envelope has gradually increased. In summer, as a result, cooling load significantly increases because of a large amount of sunlight coming through the windows. And in winter, thermal comfort can decrease at night because of heat loss and cold radiation which take place through the windows which have relatively low thermal resistance. To evaluate on characteristics of cooling and heating energy consumption under the blind-integrated window system which can fundamentally block this kind of cooling and heating load, this study has measured inner & outer surface temperature of glazing, electricity consumption and heat flux after installing the general and blind-integrated window systems in the test bed. According to the inner & outer surface temperature of glazing, the blind-integrated window system was 20.4 °C while the general one was 14.4 °C in summer. And in winter, the blind-integrated window system was 2.1 °C while the general one was 0.8 °C. Under the blind-integrated window system, in other words, electricity consumption was saved by up to 26% (about 11% daily), and heat flux decreased by approximately 34%. In addition, it's been confirmed that heater electricity consumption in winter could be saved up to 17%.