Yesterday was an 84 degree day, and I baked dinner in the oven. The house warmed up to 74 degrees. I opened all the windows last night about 9:30. This morning, the outside temperature was 44 degrees, and the house had cooled down to 65. Any cooler and the heat pump would have run.
I was very pleased with the way the house worked. The air conditioning will probably not run much this summer - another money saver!