Originally Posted by sammy37
I think 3 tons is a little big for your size house and climate.
Actually, that totally and completely depends on the house. If there's a lot of South facing glass, that house will get a lot more sun and heat up a lot more. The air conditioner won't be able to keep up. Other things play a role as well, such as how much insulation you have and how many windows and glass doors there are. Are your windows shaded, etc.
Any contractor worth his salt will always do a heating and cooling load. If they don't, kick em out and find someone who will.