What the heck is attic air-sealing? We get that question a lot. The striking thing about attic air-sealing, is that it’s probably the single most beneficial thing you can do to your house. Per dollar spent, air-sealing will result in the biggest energy savings. It will also improve comfort, by reducing the temperature discrepancies between floors and across rooms. By dramatically reducing moisture migration across the attic, it will improve durability. But what the heck is it? This 257 part series will explore everything you want to know about attic air-sealing and a whole lot more.
In simple terms, air-sealing is plugging holes in buildings. To be effective, air-sealing should take place in a part of the building that meets the following criteria:
- It must be accessible,
- It must be leaky,
- The parts that leak should be inexpensively pluggable (new word).
So what parts of the building meet these criteria? It turns out that the most popular energy upgrade – windows and doors – only meets criteria #1, but abysmally fails to meet criteria #2 and #3. In some cases our blower door tests have failed to find a measurable difference in pre and post testing of window replacement. This experience has been borne out by others running the same tests all across the country. Replacing windows and doors is expensive, and the original windows and doors probably aren’t very leaky.
On the other hand, most attics meet all three criteria. (For the purposes of this post, I’m talking about attics where the flat ceiling is insulated, the roof above is pitched and uninsulated, and access is through either a scuttle or drop-down ladder.) Attics are accessible, they leak a whole lot of air, and the cost of sealing isn’t very high.