I've had several contractors out to look at my house. It was built about 15 years ago. 2 story 3100 sq ft. House is in So. California (that means hot!) All double pane glass- R11 walls- R30 attic. Upflow furnace is in garage on stand.
Here's the problem- it does a poor job of cooling on hot days- now it's dead. Compressor burn-out. House has only 1 system for house. Furnace & coil are original to house. 80,000 btu Comfortmaker furnace I was told is a 4 ton. Coil is a 5 ton (60,000 btu). Condenser was replaced 3 years ago w/ a Goodman by previous owner. It's a 4 ton, but the factory compressor is only 42,000 btu's (I'm repeating what HVAC guys told me BTW.
I want a 5 ton. No one on this street has a system that works well & we entertain alot during the summer months. I wanted a 14 SEER but it won't fit in working area of platform. So- I'll go w/ a 12 SEER- probably the Rheem 2 stage for the short furnace so we can install an EAC or media filter under it. A couple of the guys who came out say no problem. A couple more weren't sure. I don't know who to believe. I had a Manual J performed (cost me $250.00!) & it requires 53,800 BTU's for cooling based on a 90 degree temp (it was 105 yesterday & humid as heck) so I'm not sure how accurate that calc was. Return grille is a 14x36- they say that's good. The supply may be a problem. I had the guys pull out the coil to see what size ducts were running from garage. The plenum box is 24x24- is about 18" tall & is capped off on top. What we have is 2- 12" flex lines & 1- 9" flex lines into the side of the box. The guy who seems to think it will work (the 5 ton) says the total square inches of the 3 ducts are slightly larger than 18" & will probably be ok. They have installed them many times on same duct size w/o problems.
What do the pros think? Will it work? Will I have problems w/ too much backpressure? I don't want to do this twice. BTW_ there's no access to the supply box to either increase duct size or add more outlets. I'm stuck w/ what we have. I really want 5 tons of air if it's do-able- but will settle for the 4 ton if that's my only other option.
This is suppose to be EZ- pick up phone & get it installed. The more people I call- the more stories I hear. I'm beginning to think some of these people will tell me whatever I want to hear to land the sale. I hope not.
That's why I came here- for neutral advice.
[Edited by tri-five nut on 07-27-2005 at 01:46 AM]