I have been getting bids for an ac unit in my home and I have been getting a range of 3 tons to 3.5 tons. I live in Dallas Texas and my home is pretty well shaded during the days and the majority of my windows face north or south. Thanks for any help. The ones that want to sell me the 3.5 tons say they want to oversize a bit so it will cool better when temp reaches 95+. Also it is a heat pump being installed. My home has 1450 square ft of cooling space, energy efficient window and plenty of attic installation.