Hi,
Awhile back my cousin told me to leave my air conditioner on, ALL the time in the hotter months, whether I was home or at work. (that was when I was working...) He said it would lower my electric bill cuz the AC wouldn't have to work so hard to cool off the space that had gotten hot.
He tested it for a few months himself. I figured I'd test it too - so for a few months, I left it on. And my electric bill was lower than when I'd been turning it off when I wasn't home. That was a few years back - but I still do it now and it still works - thought with the increased electric rates, "anything" helps!
Kat