Air Conditioning Systems are designed to remove (heat) moisture from the air in a given space; removing moisture makes the area more comfortable. For example, a Florida home with aproximately 1500 square feet may need a (3) three ton system to remove the moisture. HOWEVER, there are conditions called HEAT LOAD which can add or remove to the need. If the same Florida home with energy efficientcy building products, better insulation, and a properly installed system, it may only require a (2.5) two and a half ton system. Let me Load you up with this one. The same Florida home that used to have a three ton system, just removed all the shade trees from around the home. Now the home gets the full direct sun exposure, and the owner has added new lighting along with other heat generating devices. This home may now require a (3.5) three and a half ton system.