We have a wall unit (like a window unit) Air conditioner in our place. The house was built in '58 I believe and is in fantastic shape. It is 1100 square feet and the 2 ton unit is plenty for the house. -Central air actually would be MORE expensive and less efficient due to the layout of the house. Lately, the thing has been leaking water all over the wall and inside the house due to a problem with the built in styrofoam tray in the base of the unit. Apparently it wasn't designed to be taken apart that far. It is a Wards model from at least 15 years ago. We are going to sell the house soon and so far, it has been pretty warm outside. Yesterday it hit 102. It should be 105 by Saturday. My computer room in the back of the house gets MUCH hotter than everywhere else. Needless to say --yesterday we junked it and put in a model that is 3 years old that we had in the garage but had only been used for about 3 weeks. It is 1/4 the BTUs and a good bit smaller than the previous unit. Much duct tape and styrofoam cut-outs later, we had a patched hole with a new under-powered AC unit installed. Now when we sell the house, we can pull this one and give 'em $500 for a new one inside the price of the house. I hate the heat. Did I say that yet?