bundle of questions for replacing HVAC?
We live in North Carolina. Just got an energy audit done and were recommended to replace our both HVAC's. We are thinking of replacing one unit only as of now- the on 1st floor. It is outside and is an airconditioner with gas furnace. Current Size is 3 tons, 10 seer and 80% AFUE. The house has good insulation and ducting and no hot-cold spots. Our annual energy bills are summer - $563 and winter- $ 658 and baseload is $835. We have flat cost of natural gas and electricity as: July-Oct $0.998/therm and 10.15 cents/kwh, November -June : $0.936/therm 9.15 cents /KWH.
My initial questions are:
1. Is a dual heat pump a good idea in our climate in NC?
2. Is 15.5 seer enough- that has been recommended.
3. What % efficiency for gas furnace- 95% ?
4. Is Carrier infinity brand good enough? I know pricing is importnat too but was just wondering if i can resolve these initial questions it will make us easier to go ahead. We have almost no idea about all this as this is our first home bought just last year.
5. Do we need a 2 stage or a 3 stage heat pump? A 3-stage has been recommnded ?
6. What are the most crucial factors that we need to be sure of when making the final decision?
thanks for any insights!