Discovering the Culprits
Part 2 of 3 (Shadowing an Energy Audit)
The homeowner complained of temperature differentials. Wm asked where the thermostat was located and quickly solved that mystery. It was by the front door, directly in the path of the sun and on the west side of the house, which heats up in the afternoon. Her thermostat was registering the correct temperature and sending a signal to the hvac unit that their job was done. Simply moving the thermostat to the middle of the house would fix this. (You could move it to the east side of the house, but then you'd have the reverse problem in the morning while the sun was rising.) Some thermostats are wireless and it can easily be done, unfortunately, hers was not so an electrician would be necessary.
While discussing why replacing windows is not the answer to having an energy efficient home, the home owner identified one storm window that had an actual gap, but also had some moisture issues. She asked if she should get some weather-stripping, but Wm advised her to get a tube of silicone and seal it up about 90% of the way, so the moisture could still escape. "90% of the cure is better than 0%."
Now, for the fun part - blower door! The funny red door was all set-up and turned on.
The giant fan is trying to reach 50 pascals of pressure and measure how many cubic feet of air is leaving the house at that pressure. William has created a handy-dandy excel spreadsheet on which he inputs information from the house and from the blower-door read-out to determine the air tightness score of the house.
While that fan is spinning and pulling you can feel wind blowing through your house and that leads you to the leaks. Wm goes to each interior door and closes it with just enough room for his hand to still be in it and feel how much air is moving and even if the draft in that room is strong enough to noticeably push against the door.
The usual culprits - attic stairs and basement were blowing a light breeze, but much to my surprise, it wasn't the most significant draft. The bathroom had the most movement. We inspected the bathroom closely and found that the electric sockets and vents had their own little weather system with plenty of breeze flowing through. Air coming through the electric sockets indicates no or ineffective insulation in the walls and the attic. Then Wm had the homeowner touch the windows as well to help contradict the oft held belief that the problem is windows. There was almost no air moving from the windows.
With this information from the bathroom, Wm whipped out his handy dandy manometer - a tool that reads the pressure differentials between the house and the ducts while the blower door is operating - which can help determine if your ducts are leaking. They were leaking! We found one of the significant problems! This isn't usually a main issue, but for this home it was. When we started the audit that day, the ducts were not high on our suspect list, but by carefully following the clues Wm identified the worst culprits.
Now for writing the report. Wm likes to keep mulling over the house as a system for a couple of days. He stresses over these reports, making sure they are the absolute best and most helpful recommendations he can make. In the evening in the middle of an episode of "Comedians in Cars Getting Coffee" he'll blurt out a seemingly random new angle he's considered for that house or I'll hear him talking to himself around the house until finally he is satisfied with the report he's composed. This means it's time to sit down with the home owner and review the performance of their home and our recommended solutions for problem areas.
Up Next: Part 3 Performance Scores, Recommendations, Follow-up Meeting
Part 1 Turns Out It's Detective Work
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