Hello I have a 3 ton goodman system. Its cooling aprox 1200 square feet. My contractor has his duct work set up with 2 main branches. The main branch whiches goes to the bedrooms is 12 inch round ducting with another 10 inch branch going to our living room. If we wanted 2 tons of cooling to the bedrooms wouldnt this branch line be to small? I am asking because the unit is not cooling the rooms enought. Thanks for any help you guys can give him. He hasnt been much help.