clarkecu wrote:
I think it is always better to have too large of an AC unit then one that is too small.
Most manufacturers recommend slightly under sizing an AC system.
While the general rule is one ton of AC size per 1000 square feet of home, a home needs to be assessed - square footage - sun exposure - size and number of windows etc.
But in general, you are better off with a slightly smaller AC than a larger AC.
There are two reasons for this.
One job of the AC is to remove heat from the home, the other is to remove humidity from the air in the home.
1 - A slightly undersized AC will run longer with fewer stops and starts increasing the life of the compressor.
2 - and more important, is that an oversized AC can create an less comfortable interior climate. Because they are large, they cool the home quickly but they do not run long enough to remove humidity from the home. The sort cycling can cause premature compressor failure and you can end up with a cool but humid home that is not comfortable.
Say you have a smaller 1500 square foot home with a mature tree or two in the yard on the south or west side of the home. In this case a 1.5 ton AC would be a better choice than the larger 2 ton. It may run a bit longer to keep the home cool but the longer run time will enable the system to remove more humidity making the home more comfortable.
If you Google "oversized air conditioner" you will see a number of articles on that subject.