I live in a 2 story home. We have 4 different window AC units in 4 different rooms. Obviously we aren't in all four rooms at the same time, but we do use all 4 areas at different times throughout the day. I am wondering if it is more energy efficient to keep all 4 running at a low setting to keep the whole house at a constant temperature. Or would it be better to turn the units off and on according to when we are in each area of the house.