Hi Pros! Have spent the past couple of weeks lurking/reading/learning.
I'm looking to replace a 13 year old R-22 A/C, and would like your suggestions.
2422 sq ft. house (~1210sq ft main floor, 1210sq ft 2nd floor, semi-unfinished basement - to be finished in the future)
Back of house faces west with 8'x8' patio door, kitchen with 2 windows, and family room with 3 windows on main floor back of house, and master bedroom w/4 windows, main bath w/2 windows, and 2nd bedroom w/2 windows on 2nd floor back of house.
Typical heating season is 4-6 months, and typical cooling season is 2-4 months (rest of the time, windows are open/closed as needed)
Current issues include AC system struggling to cool house on 35-40C (100-115F) afternoons (approx. 20 per year), and frosting of pipe on AC unit (freezing of pipe was caused by Filtrete Ultra filters in furnace - removed & freezing went away, now just frosts up on certain days). Moderate days (25-35C / 80-100F) system works fine.
House built 1999 with York Diamond 90 gas furnace (P3URB12N07501C 92.0 AFUE 80K btu/hr) and International Comfort Products High Efficiency 5000 air conditioner (NCA5530VKD2), and General Whole Home bypass humidifier (with manual knob control). All airflow control is done manually using the duct dampers/registers (I close east side (50%) mainfloor & 100% of basement in summer for better cooling upstairs, open all in mainfloor & basement in winter for heating).
Have received 9 quotes from various Carrier, Trane, and Lennox dealers. All have quoted 2.5 ton single-stage units as follows (except where noted);
Carrier Comfort 16
Carrier Performance 16
Carrier Infinity 17 (3 ton, 2-stage)
Lennox Elite XC14
Only 1 has suggested replacing the furnace to get the variable speed motor - all others say that the furnace could last another 3, 5, or even 10 years before needing replacement.
No plans to sell house at this time, but will be selling in 10-15 years time.
I asked for a quote on the 2-stage AC as I felt that a 2 stage might help with the AC struggling on the hot, humid days in high mode, and operate in low mode on the moderate days.
A new outside compressor as well as a new indoor coil is required. The indoor coil seems to be a factor for SEER rating, as only certain size coils will fit on the York furnace. (The SEER rating will determine the power rebate amount, and in some cases, larger coils are required to get to 15 SEER). Noise is not a factor as the outdoor AC is on the south wall near the front of house (with furnace just on the other side of the basement wall).
Keeping me awake at night are these options;
1) buy a single-stage now as a straight replacement with standard coils
2) buy a single-stage now with more efficient (larger) coils
3) buy a two-stage now, that can marry to a new furnace 5+ years down the road
4) buy a whole new system now (single or 2 stage AC + 2 stage ECM furnace + automatic humidifier)
Pros, any suggestions on which option to pursue based on your experience in terms of fixing similar issues that I've relayed above?
Thanks in advance!