I have the thermostat set at 79 degrees in the summer when I run the air conditioning. What percent savings be achieved by raising the thermostat by two or three degrees to 81 or 82? I live in Arizona so humidity isn't a factor. My A/C unit is 5 ton, built in 1995, but has only had 11 years of use since first owner of house was never present in summer. I don't know what specific number insulation the house has, but it's the blow-in type in the attic vs thick pads. I don't change the thermostat, but rather leave leave it at a set temperature.