I am sure it costs more to keep a house air conditioned at, say, 72 degrees than at 80, and it costs more to use the a/c than an attic fan on cooler days. But I've always heard different opinions about leaving the a/c off or set at a higher temp while we're at work all day and turning it on when we get home. I've been told it costs more to cool a house from 95 down to 76 than it is to leave it at 76 to begin with, because the a/c uses more energy and works harder to cool an entire house than it does to maintain a cooler temperature. We normally leave the a/c at something like 80 while we're gone and drop it a bit after we get home. In the winter we normally set the furnace at 60 if we're gone all day (and when we go to bed at night).
What say you guys?