Solar energy through glass windows has an influence on the thermal environment in the cabin and thermal comfort of occupants. A medium-size electric vehicle (EV) is conducted for evaluating the performance of solar reduction glass under summer conditions in the climate chamber by experimental measurements. For this purpose, two kinds of glass are attached to the medium-size EV with different performance of solar reduction rate (IR-cut type and normal type). In this paper, two types of experimental measurements, steady state and unsteady state conditions, are conducted. Surface temperature, air temperature and electric consumption of air conditioner are measured under some conditions of air-conditioner. EHT (Equivalent Homogeneous Temperature) by thermal manikin, thermal sensation and thermal comfort by male and female subjects are also measured. Significant difference in the measured surface temperature of the instrument panel where solar radiation reaches through the glass window is found between IR-Cut glass and normal glass. In addition, one or two rank difference in the thermal comfort at the part where solar radiation reaches is found, and “hot” thermal sensation and discomfort in the female subject is much improved. Heat load of the air conditioner can be decreased by 20% from the view point of controlling the air conditioner by thermal comfort of the occupants. The solar reduction glass such as IR-cut glass has a significant influence on the thermal sensation, thermal comfort of car occupants and electric consumption of EV.