The new HVAC system was installed this week and on Monday they put in the new insulation in the attic and did all of the air sealing, including fixing the attic door and sealing the house fan. Today they ran a follow-up blower test to see what difference all of this made. They had missed a couple of things on the first pass, so they sealed around the ash dump door in the back fireplace and installed some weatherstripping on a door. They said the air leakage had improved by 30%. That didn’t seem like that much to me since the house was very leaky before. One thing we found was that a lot of air was leaking from the back room which has wood paneling. Apparently, air was being sucked down from the attic of the back room, down the walls, and out the joints of the paneling. The only way to seal that would be to caulk all the joints of the paneling, overlay the paneling with drywall, or replace the paneling. That would be great, but that’s more than I want to do right now. You could feel a breeze blowing from those joints, but they also had a pretty powerful fan sucking all of the air out of the house. There wasn’t a way to seal from above because that room has a low flat roof that isn’t accessible.
The supply and air vents were measured for air tightness as well. The reading is supposed to be below 1.0 for each vent and there were a couple that were higher than that. Part of that may relate to the way the “boots” for those vents fit into the wall opening, leaving a small gap that lets in air from the crawlspace. The HVAC guys didn’t really mess with the boots at all, just tied their ducts into them. I will see if they can make some improvements to that, though I think that is kind of beyond the scope of their work. The guys that were here today did caulk the worst one and brought the value down a little.
Even with all of the leaks, their software calculated that I could save about 28% on my energy costs, qualifying me for a $1450 rebate from Georgia Power. If you can get to 30%, you can get an extra $400 rebate from Georgia Power. So they started trying to figure out ways to get another 2% that would cost less than $400. One idea they had was a water heater blanket which would bump it up another 1% and would cost $100. They asked how many incandescent bulbs I had in the house, but I don’t have any, so that wasn’t an option. I asked if they had entered the SEER value of the new air conditioner at 15.7 SEER. They had included the original work estimate which included only a 13 SEER unit. The condenser I have is actually rated at 14 SEER, but the installers were able to tweak it and get up to 15.7. Just to be safe, they entered 14 SEER and got just over 30% savings to 30.2%. Then we were talking about rebates and I mentioned I could get a Georgia Power rebate for half of the price of the thermostat they had installed. This turned on a light for them, so they said that was something they could enter into the software. With that thrown in it went up to almost 34%. I had a programmable thermostat before but I think the software model may not take that into account, or it could be that a manufacturer’s thermostat will just operate the equipment more effectively than the old one I had from Home Depot (which was a pretty old model). I think that would be more true with the variable speed systems than mine, but I don’t really know. It’s all theoretical since they can’t measure actual savings without waiting a year and seeing what happens.
Anyway, there is no way the rebates and tax credits will come close to paying for all of this, but overall efficiency rebate paid for about half of the attic and sealing improvements (though a lot of the overall efficiency was due to the HVAC system and new ductwork). And even though I don’t pay that much for heat and air conditioning, I think I should see a significant change in my power and gas bills.