Smart thermostats solve this problem by learning your habits and either maintaining a moderate temperature while you are away, or turning off completely then coming back on just prior to your arrival. This means when you walk in the door, your AC doesn’t have to work as hard to achieve the temperature you desire.
A smart thermostat can learn your habits, like a routine where nobody is home Monday through Friday from 9 am to 4 pm. It would then adjust your programming to power down the AC at exactly 9am and come back on again at 3:30pm. Coming home early from work and your smart thermostat doesn’t know? No problem, your mobile phone will let your smart thermostat know automatically so it can prepare the right temperature.