AC Issues and Repair/Replacement Quotes
I have a two story house in Cincinnati, OH with two split gas furnace systems that heat and cool the place. The second floor of the house (approximately 900 square feet of finished living space and approximately 800 additional square feet of "2 story living area" comprise the second floor. The house is 7 years old (as are the HVAC systems) and is well insulated.
The upstairs system today is comprised of a 60k BTU 90% carrier furnace (58MCA060) with a 2.5 ton coil (CK3BXA030) and a 2.0 ton 10-SEER, R22 Carrier outside condenser (builder's grade). We have only lived in the house since October, and the furnace seems to heat the second floor without too much issue and keeps the place comfortable in the winter. This summer, when we turned on the AC for the first time, we discovered we were low on freon due to a leak in the evaporator coil. We have had the unit filled with R22 and the house is cool (for the time being). Unlike the heating, the cooling of the house is challenging in some rooms. The furnace sits in our attic and feed 11 registers and have four return air registers. The air flow just seems a bit low. Also, humidity is a bit of an issue on the second floor of the house. However, it is presently keeping the second floor at 76F without issue.
The registers are fed with a series of insulated, flexible ducts in different sizes. Most are reasonable in length (4'-12'), a couple are a bit longer (about 15-16'). The flex duct is taught and not kinked.
At first, we thought we'd just replace the coil. However, quotes for replacement are running $1500-$1800 and universally all the contractors have advised against just repairing the existing unit.
Instead, all have recommended replacing the coil and outside unit with a new system. I have received quotes from three different dealer on replacement units. Also, two of the three dealers are recommending changes to the existing ductwork. I'd appreciate any expert opinions on these systems and their recommendations:
DEALER # 1 -NATE Certified
Trane XR15 (2 ton)
Trane CC 17.5 SEER coil (cc)
10 year parts / 1 year labor
Flush & clean existing lines. Use existing programmable thermostat (Carrier)
recommends installing new unit first and only making changes to duct work if issue persists with new unit. Says current duct work appears "ok" and new units are stronger than older ones and may be fine. Duct work changes could be addressed after installation if issues continue. Says that might increase diameter of longer runs.
DEALER # 2 - NATE Certified
Trane 4TTR5024 2 ton
Trane 4TXCB025 coil
Clean, flush, and reuse existing line set.
Use existing thermostat (Carrier programmable)
Change 2 supply runs (further away) to larger diameter (included in the bid)
10 year parts / 3 year labor warranty
DEALER # 3 - NOT NATE Certified
Install 2.5 TON Trane system (not 2.0)
Clean existing line set with RX-11 and nitrogen and reuse
Trane XR13 system with 10 year parts / 5 year labor $3,620
Trane XR15 system with 10 year pars / 10 year labor $4,445 - includes 4TTR5030A1000A coil
Trane XL15i system with 12 year compressor / 10 parts/10 labor $4,810 includes 4TTTX5030A1000A coil.
This dealer also recommended reinstalling (8) 6" RIGID supply pipes in place of the flexible duct that lead to the bedrooms and bathrooms. - $1,110
Sealing off (3) supply ducts in attic (these currently supply closets) - $185
I have mixed feelings about the contractors, but I would love to hear what this group thinks about these bids and recommendations.
Also, I'd be interested in what this group would think about possibly replacing the furnace as well with a variable speed unit (this would allow us then to qualify for $900 in rebates). How much extra cost could I expect to add for this? Would you think it worth it?