I'm having my 17-year-old gas furnace and A/C unit replaced. My current A/C is a single-stage 2 1/2 ton unit, and that is the correct size based on the load calculation.
I live in a 3-story townhouse and on very hot days (all of late spring & summer), the top level is more than 10 degrees hotter and more humid than the main level of the house. It's VERY hot upstairs.
I'm getting a new Trane 2-stage gas furnace with variable speed blower, and I'm trying to figure out if I'd be better off with a 2 1/2 ton single-stage A/C or a 3 ton 2-stage A/C (the 2-stage units do not come in half-ton sizes). I'm hoping to achieve maximum cooling/dehumidification on my upper level. HERE'S MY MAIN CONCERN: It's my understanding that if an A/C unit is too big, it will short-cycle. So if the right size unit for my house is 2 1/2 tons, will getting a 2-stage 3 ton unit be a problem and cause short-cycling on the hottest days? My top priority is properly cooling the upstairs and I'm not really concerned with monthly $ savings.
I'm worried if I make the wrong decision I might be stuck for many more years with an unbearably hot upper level. My contractor thinks either unit would be fine. Anyone who has experience with this type of situation, please help me make an educated decision. Thank you!