Our furnace is approaching 25 years old and we have no cooling capabilities, so my wife Michele and I are looking into buying some new equipment before the temperature climbs this summer. I am especially interested in installing a mini-split heat pump, which would allow us to get rid of the ductwork and furnace in our unconditioned attic. But the initial expense may be a hindrance.
We knew that the Energy Upgrade California (EUC) incentives for retrofitting our home would not be around forever, so I contacted the EUC folks and picked an HVAC contractor, Stewart Heating and Air. I had met Bill Stewart, an icon of the HVAC and energy efficiency world of the Bay Area, at an EUC intro meeting at our local library three years ago. Bill’s company was getting customers $4,000 back for $8,000 of work through the rebates offered through the EUC program. Scott Mellburg of BayREN is our EUC advisor and is standing by to help us through the process and meet with us and our contractor any time we think it will be helpful.
Basically there are two ways to get the rebates. First, you can choose from a set of measures from a list that includes air sealing, adding insulation, and other retrofits. The measures you choose determine the amount of the rebate. Second, you can drop your energy use, according to modeling, by 10% for a $1,000 rebate, up to 40% for a $4,000 rebate. Michele and I are leaning towards the latter, even though we had air sealing done and insulation added to our attic several years ago, and it may be difficult to reach that 40% energy savings.
This morning Rich Cunningham from Stewart came to do the energy audit. He performed the usual blower door and duct leakage measurements, took some electric plates off the outside walls to confirm that the walls have no insulation, did a number of safety checks including measuring CO levels, and looked at the crawlspace, among other things. Instead of depressurizing the house, Rich pressurized it to do the leakage testing.
Michele and I were working last night to clean out our fireplace, and I was pumping caulk into the space between the walls and the floor near the fireplace. Last time we had a blower door test done, the house was depressurized and we had some black soot spewing into our living room. No problem this time, with the pressure aimed out of the house and not into it. Rich explained that for some customers, feeling the air rushing into the depressurized home is a direct learning experience. The last time we had work done on the house, we could feel the air rushing in through the unsealed can lights all over the house. But we were sold on air sealing already and didn’t need the dramatic demonstration for a second time. In fact, our house may now be a little cleaner than it was last night after being pressurized.
Rich also pressurized the whole house, not just the ducts, to 25 Pa before doing the duct leakage testing. This is called “testing leaks to the outside”.
In a week we will sit down with someone from Stewart Heating and Air to discuss the results of our audit, possible measures to install, and possible rebate amounts.
Here are the numbers so far (stay tuned for more):
Table 1. Air Leakage (CFM50)
Sept 2007 test in air leakage
Sept 2007 test-out air leakage
April 2014 test-in air leakage
April 2014 test-out air leakage
Table 2. Duct Leakage
Sept 2007 test-in duct leakage
Sept 2007 test-out duct leakage
April 2014 test-in duct leakage
April 2014 test-out duct leakage