I am replacing an 18 year old Trane heat pump in a house of the same age. I live in very humid Tampa, Florida, where heat is needed at most 10-12 days per year, while the a/c runs day and night for 6-8 months per year. The old Trane is a 2 1/2 ton, and the house was originally 1400 square feet. Since then, a 400 square foot back room has been added, bringing the total to 1800 square feet. The addition is ducted with overhead vents, but the air barely reaches the room. If not for two glass doors, there would be virtually no heating or cooling the addition. I've talked to three contractors so far, but their information seems confusing or contradictory. First, all three recommend a new 12 SEER unit. The say that anything rated higher won't save enough electricity to warrant the additional cost. But 12 SEER seems on the low side, especially considering the new government minimums. Also, they differ on size recommendations: One says stay with 2 1/2 ton. He claims that anything larger would necessitate replacing all the duct work. (However, he said this without ever examining the existing ducts.) Another contractor recommended a 3 ton, and the third said 3 1/2 ton. (These would be the sizes of the outside compressor unit, with the corresponding air handler 1/2-ton bigger in all three cases.) Finally, the three guys all want to sell me different names: Carrier, Bryant, and Payne. I wonder if you could provide some solid info to cut through the confusion. Also, any other considerations or recommendations (i.e. Puron vs. Freon) will be appreciated. By the way, I have lived in this house less than a year, so I have little extensive past history of the existing unit, comfort level, etc. But I do know that the current electric bill runs at least 50% higher than it should.
Thanks for your consideration.