Many homes used to be inefficient when it came to maintaining a comfortable temperature in homes, and many homeowners installed an air conditioner that was able to provide more than the required capacity, in an effort to compensate. Today's more energy efficient homes don't have that problem.

Improved home insulation, weather stripping, caulking, and better energy efficient windows are some of the steps that Houston homeowners have taken to deal with the high temperatures. However, many homeowners end up replacing their old air conditioning unit for a newer unit of the same size, without realizing this isn't helping them a great deal. The situation isn't helped by the fact that if your current system is about 10 years old, the BTU ratings aren't the same as on a new A/C system.

You may end up with an air conditioning unit that's undersized or oversized if you go by the specifications on the nameplate on your old unit. And it can cost you thousands of dollars if your unit just isn't performing as you expect it to, on top of the actual price of the new unit to begin with.