I am a confused home owner - HVAC is not my field, and for good reason. I would be grateful for any advice from experience here...
I have a 2700sq/ft single story home with a split system - A/C compressor outside, gas furnace/coils in the attic - in the Upstate South Carolina area. I have two 20x25 returns, 22 supply vents, 16" return lines, 8" supply lines (with a lot of Y's that need to be fixed). Most of the house does have 12' ceilings and I have a ton of windows/french doors.
I currently have a 16 year old Goodman 10 SEER 4 ton A/C with a 5 ton system in the attic. I have only been here about 4 years and have dropped about $1,000 keeping it running and am being told it needs to go by two different contractors. The unit has never been able to really do a good job of cooling things down in the Summer, though the heat works great.
I have decided I am going to be here for a very long time and want to do this right - not just a band-aid until I can sell. That said, I have had 5 companies give me quotes.
Trane - Nice units but spec for spec I am getting about $2K higher estimates on Trane than Lennox and I am unable to see a justification. Warranty on both as well as other performance specifications seem the same on the models I have compared. Perhaps the rep didnt know enough about the units? In any case, I have not been sold on Trane.
Lennox is my next choice. I also looked at Goodman and Rheem, but Lennox and Trane really seemed to be head and shoulders above those. Maybe just better sales reps...?
In the Lennox line what is being recommened (partly due to my wanting the best long term investment) is the XC21 series matched with the SLP98V furnace. Also getting the air purifier, the iComfort Touch controller and some duct work modifications.
So my question: I have 2 guys saying I need a 5 ton unit, 2 guys saying I need a 4 ton unit and 1 "whatever you want". The 5 ton units are much lower SEER ratings, but aside from a piece of paper I have no real world idea what is better. I tend to be one of those "if a little is good, more is better and too much is just about perfect" kind of guys. I am not sure if that works in HVAC though. Is too big a bad thing? WIll it shorten the life of components, not dehumidify enough, not be energy efficient?
Thanks for any advice!