I recently did a blower door test on a house that was built in the early 1990’s. As expected it was very leaky, and I made suggestions to address the leakage.
Here’s the kicker. As leaky as this house was, it still passed the newly introduced National Construction Code requirement for air leakage. The new code requires an air permeability rate of no more than 10m3/hr.m2 at 50 Pascals. The house tested at 9.2m3/hr.m2. So far with my testing of houses of this vintage, this result is pretty typical.
So, what does this mean? Firstly it means that the current requirements set the bar very low, and are pretty easy to meet, (without really having to try). Secondly, and more optimistically, it means that we can easily implement some simple air sealing strategies into our new homes without breaking the bank and resulting in a great improvement in efficiency.
The challenge we face is to convince home owners that these air sealing strategies are worth implementing. Written reports and verbal advice are often ignored. A blower door test is a very tangible way to show people the effects of poor air sealing but this test is done after the house is built. Implementing air sealing strategies after the house is built is more expensive and less effective than doing it during construction.
When it comes to energy efficiency, air leakage is a big deal. It’s hard to keep a house warm if the air that you are heating keeps escaping. The air that escapes is replaced by outside air which then needs to be heated. It’s like trying to keep warm water in a leaky bucket and having to continuously top up the bucket with more warm water to keep it full. Do you really want to live in a leaky bucket? . Click here to go to my previous blog post about how much outside air you are heating or cooling. Click here to see a leaky bucket.