 Make sure that you've got all those heat things in your house. If you've got a heated tile floor in the bathroom, turn that stuff off. Anything that's generating heat, the clothes dryer, only use that early in the morning at the coolest part of the day so you can help ventilate things out. Only use that stuff that creates heat when you need to. So heated tile floors, shut them off. Otherwise, you're paying to heat that and cool. You're just fighting it.