Just a little background. Our house is 2,000sqft in hot/humid NC. The house is 2 story and is 22 years old with the original 3-ton Carrier heatpump. Just one unit for both floors. The temperature difference can be 8-10 degrees different between the 2 floors. Other than the system is very old, the temperature difference is the reason we are replacing. Oh yeah throw in a goverment check, so its time for a new heat pump.
Two contractors have inspected my house and will be getting me quotes in a few days. They both noticed the small return and supply duct (10") coming from the 2nd floor and saw very little space for a bigger size. The working space is a vertical shaft from the 2nd floor down to the crawl space.
Contractor (A) recommends a dual zone (2 thermostats) system and Contractor (B) says to do two systems (one unit per floor). In fact Contractor (B) refuses to give me a quote on the dual zone because of the small return/supply from the 2nd floor. He is adamant about the dual zone not being able to send enough cool air up stairs when the system is calling for it because of the smallish 10" duct.
I have another contractor coming out next week but kinda confused right now.
Sorry to run long. I described the best I could. Any thoughts on this??