The energy saving and comfort were investigated under the same experimental conditions in enthalpy difference lab. The results show that the constant-speed air-conditioners can make the room reach the set temperature quickly under the same conditions. When the power consumptions of the constant-speed and variable-speed air-conditioners reach the same,the time is 11 hours at the outdoor temperature of 35℃ and 6. 3 hours at the outdoor temperature of 40℃,so the higher the outdoor temperature is,the earlier th...