If you’re thinking about weatherizing your house without an energy audit, think again. I just had my new home receive an energy audit and though the formal results haven’t been processed yet, the experience was fascinating as always. Going into it, my assumption was that the house would need better insulation in the attic and around the rim joist. These assumptions were quickly confirmed, but there were many other areas of needed improvement that even the first steps of the audit didn’t pick up.
For example, prior to running the blower door test, our energy auditor will take infrared photos of numerous locations throughout the house and record data, such as surface temperature, and the image itself. When we did this, the usual problem places for fiberglass insulation were revealed. But after we ran the blower door test for a while, allowing the system to draw in cold air from the outside through unsealed cracks and crevices, a new image was formed with the infrared camera. One place this happened was in the master bathroom where the wall hiding the exhaust pipe had no insulation where it joined with the exterior wall. This essential resulted in a conduit where the warm surface of the interior wall bled right out through the exterior along this viaduct. Another trouble spot revealed by running the blower door and the infrared together was above our open, Cape home entry way. The exterior wall above the door (which happens to run beneath a porch roof) had no insulation what-so-ever. In fact the more we looked, the more problems we found. While the first photos showed little trouble, running the blower door test revealed steady air infiltration between the first and second floor. Where the image showed no problems before, now the strapping and floor joist were clearly visible. This is a bad sign. It shows that the environment is not being effectively controlled.
Running the blower door test requires the same process. The first results of the test showed an air change of 1700 cfm. Pretty good for a house conventionally built, though not up to the standards of new efficient construction. As George, our auditor put…”not bad”. That assessment of course comes with a caveat; that caveat being the smoke test. The smoke test simply involves using a device, much like an automatic match-stick, that produces a puff of smoke instead. When George puffed the canned lights in the kitchen, we watched as the smoke was quickly sucked up into the light system. This is a major problem my assumptions overlooked. The analysis was simple. Often times, insulating the space between the top plate of a wall and the bottom plate of the next wall (around the rim joist) is overlooked. In cases like this, cold air outside simply rushes between the clapboards, through the seams in the sheathing and right between the floor joist running along your ceiling, effectively cooling a large space. Because nature is always trying to create balance, the warm air in the house takes the exact opposite path, running head on with the cold air and directly outside the house. That’s the energy you paid for from the money you made through hours of work rising up to the atmosphere because the original builder of the home didn’t have the knowledge, the experience, the sense or the cost/benefit desire to build the home right. He was only thinking of sticks and nails. Now you have to fix.
The first step – get the energy audit. Don’t go blindly spend $15k on windows. There’s a lot more low hanging fruit to be found first.
p.s. I forgot the fourth sense. Analyze your appliances and heating system. Our house requires about 60,000 btu to heat. The ding dong who built the house installed a furnace that runs at 120,000 btu. It doesn’t take a builder to figure out the problem there; just a careless one to not even consider the matter.