Posted by: lcowie | November 16, 2010

First Time Energy Auditing

I have a quick tip for all those preparing for their first energy audit inspections: check the attic first, then the basement.

Due to the Stack Effect, hot air rises to the top of the house and escapes through insulation gaps in the attic. You will know if there are insulation gaps in the home if you examine the attic. It depends on how the homeowner treats his or her attic. Most people treat their attics as an unconditioned part of their home, which means the insulation should be on the attic floor, thereby connecting the attic essentially to the outside. Other homeowners treat their attics as conditioned space, in which they may have a child’s bedroom or some other kind of livable room. In this case, the insulation should not be on the attic floor. Rather, it should be on the top walls of the attic, keeping the heating or cooling side the attic and the home.

The attic is generally the best place to check for gaps because the Stack Effect naturally exposes the pressure difference within the house. Is your attic incredibly warm, while the rest of your house is cool? That’s the Stack Effect in action. Insulation also plays a role here, so keep in mind how the homeowner intends to use the attic.

The reason why you should check the attic first is not only because the gaps are likely there, but if these gaps get closed, the Stack Effect will be reduced. Even if there is still a gap in the basement, there will be less of a need for infiltration if the hole in the attic is closed. The Stack Effect will be diminished because there won’t be an influx of uncontrolled air, and there won’t be a need to replace any air. As I mentioned in another post, when one cubic foot of air escapes the home, one cubic feet of air will replace it. If you seal up the hole in the attic, no air will leave, so virtually no air will enter.

Once you have secured the attic insulation, you shouldn’t stop there. You would be doing an incomplete job if you walked away from the basement knowing there was a hole there! A gap in the basement insulation is also a problem. You may have reduced the Stack Effect, but the gap in the basement may still bring in air from the outside – air that will be exfiltrated through a gap somewhere else in the home. Homeowners do not want air from the outside coming into their homes.

So when you go to the home where you will be conducting your first energy audit inspection, check the attic first, and then the basement. It’s important to check the attic before the basement because the Stack Effect will make any gaps in the insulation very obvious. These are the two hot spots that you want to pay attention to, before anything else.

Leave a comment if you have anything to add about attic and basement gaps or if you have a “The first time I conducted an energy audit…” story!

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