Hi, this is my fist post, hope I include all the relevant info - this forum is super informative.
I live in Houston, TX in a 2 story townhouse.
House has 2 A/C systems (upper floor about 900 sq ft). The upstairs system (original, 13 years old) is a 10 SEER, 3.5 ton condenser, 4 ton furnace, and evaporator. The fan motor on the condenser is new and the system needed some freon 2 years ago and new capacitor (twice I think in the last 3-4 years).
For upstairs, the plenum and evaporator areas have a lot of mildew as well as poor seals (gaps between parts in the attic) and I finally decided to do something (replace them). I am also a bit worried of the air quality. I use the 3M Ultra allergen filters in the return (30x20x1).
My first dilemma is this:
1. should I just replace the plenum and the evaporator to eliminate the existing mildew? This does not sound like it's going to eliminate the cause.
2. Should I replace the evap and furnace with a variable speed unit with humidity sensor that would adjust the aiflow, hopefully preventing recurrence thereof
My 2nd question:
If i go for the furnace+evap, should I do the whole system? I expect we'll be in this house 5-7 more years, so if the current system is going to break during that time, I might as well change it. On the other hand I have a home warranty that will probably replace the compressor when it breaks.
I talked with 2 companies listed in the EBSCO Research Best Pick report and they both described good quality work and quoted me 2 systems (to choose whatever parts I want):
1. American Standard
Honeywell 8000 control panel
Tech told me they install a humidity sensor in the furnace outlet that will be used to adjust fan speed as needed (var speed)
Plus resealing all air outlets at drywall and the 2nd A/C unit (I asked for this)
furnace md# 58cva.
controller will be the infinity - can also dynamically adjust blower speed to control humidity
Plus same resealing as above
Did not give me the P/N for the condenser, since I had primarily asked for the furnace + evap
Carrier system (2nd company) is 3-4 thousand more expensive than the other -- why? is it worth it? (not sure if I'm allowed to post the actual price quotes). My electricity bills are not too high, so efficiency is not a big issue.
It's a big chunk of money, so I would appreciate any advice/guidance on:
- what should I replace?
- Which system is a better value
- anything important I am missing / missunderstanding?
- anything else to ask the contractors?
Thanks a lot in advance.