It was hot driving across Arizona, but my father refused to turn on the air conditioning. "You know that if I turn on the air conditioning, we only get 16 miles per gallon. Right now, we're getting 18" I thought that I was going to die from the heat when my mother said, "You know George, turning on the air conditioner really isn't that expensive. And it's a whole lot cheaper than getting a divorce. " My father took the hint and turn on the air conditioner. But I got interested and started figuring out how much it did cost per hour to run the air conditioner. We were going about 55 miles per hour out there in the desert, and the gas cost 1.60 per gallon. How much did it cost to keep cool?