The indoor temperature regulator is a machine used in cooperate with an air conditioner. Its purpose is to control the indoor temperature for a long time, thereby reducing the energy consumption of air conditioning in summer and providing a new attempt for a green and sustainable lifestyle. Using phase materials as a storage medium to store heat air during the day, and then taking advantage of the temperature difference between day and night to release the heat in the material at night, can help reduce energy consumption from air conditioning use in summer.