Air-conditioning not only cools the air, it also cools the solid materials inside the house. That acts as a bank of thermal inertia. If you keep switching off t

Air-conditioning not only cools the air, it also cools the solid materials inside the house. That acts as a bank of thermal inertia. If you keep switching off the air-con, those materials never get to reach a cool temperature too. For those who advocate turning off the air-con during the day, tell me, do you switch off your refrigerator during the day too? Much better to have the the air-con 'idling' all the time rather than working either 'flat-out' or 'off'. The same arguments also apply to heating as for cooling. Read up on duty-cycles.