I have a 4 ton 10 seer air handler. My house is 1485 square feet. I want to get a 14 seer condenser, would a 3 or 3 1/2 ton be more efficient?

Thanks

Gary

Can't tell without a manual J calculaion. Manual D is used to size ductwork, Manual J heat and AC. A lot of stuuf goes into the analysis. See HVAC Software, HVAC-Calc for Heat Loss, Heat Load Calculations

Changing seer does not make it so you can change the tonage... get a consult before doing anything from a local company. Most will give estimates for free and they can do a heat load calculation.