I have a 2-story home with 2 A/C units. The master bedroom is down stairs and the other bedrooms are upstairs. During the summer, we are all sleeping upstairs so that we do not have to cut the A/C on (Energy Savings?) I would like to be able to sleep in the bedroom down stairs but my spouse wants to conserve energy (Bless her) and wants to stay upstairs. I.E. will keeping both A/C units on during the night utilize more energy relative to having 1 A/C running upstairs?