Hello, I want to request some help on some HVAC + insulation choices:
We (Me, Wife, 2yr old, 6mo) live in a 3500 sq ft home in the upstate of SC, built in 1950. We currently have a 2-zone HVAC with a 3 ton 12 seer system(I think) each upstairs and downstairs. The outdoor units are from 1990 and the furnaces are 80,000 btu units, 92% efficiency, which were installed in 2006. I assume the efficiency of all the units has gone way down since installation, but I'm not sure how much.
Currently the upstairs ducts are duct board with flex tube to the vents, while the downstairs is metal to the end. Only one return upstairs, but downstairs has a separate return for each room. Our total utilities bill is $4,500ish, and I estimated a heating load of 74 mil BTUs and 13 mil BTUs of cooling. I try to keep the thermostat at a reasonable level, 67 in winter, 78 in summer.
The attic insulation is very poor, maybe 2-3in, and I am currently working on sealing the house. I am unsure of how to measure the wall insulation, and the house has an unfinished, uninsulated basement. I am also in the process of replacing the windows, and they seem to be really poorly sealed too.
I got a HVAC company to come in and check the units as they are quite old, and they gave me the following estimates for replacing the systems:
Option 1:
Replace AC units with 16 Seer units(York YCG), upgrade electrical to current code: $11,253
I assume these units are also 3 ton, but the quote did not specify
Option 2:
Option 1 plus switch out furnaces for 80,000 BTU 96% ones: $17,119
Option 3:
Change to 19 Seer 3 ton, 2 stage heat pump(York YZT) paired with 96% furnace: $22,453
For this one, I could get the 30% tax break up to $2k, so it's really $20k.
Obviously, I need to work on the sealing and insulation, but I wanted to get y’alls advice on how much I can reduce my heating and cooling load by doing that, and if you would replace the furnace as well as the AC, as those are pretty clearly on borrowed time. We plan on living in this house at least until the kids are out of the house, so we’ve got a pretty long timeframe.