Redo of Blower Door Test

Way back in 2015 before we moved into the house we completed a Blower Door Test. Check out my previous post for a more thorough breakdown of the testing and our rationale for decisions/assumptions. Briefly though, a Blower Door Test assesses the airtightness of a building – basically, how leaky/drafty a building is. It probably goes without say but an eco house should not be drafty. Drafy = bad. Airtightness is rated based on “air changes per hour a 50 pascals of pressure” (ACH). Typical construction in Canada these days reaches about 3 ACH. The Canadian R2000, our high-efficient energy standard, is 1.5 ACH. While the Passive House standard is the most ambitious and rigorous target of 0.6 ACH. These days, pretty much anyone shooting for an energy efficient target has their eyes on the Passive House standard – even if not building a true Passive House per se.

Although that was the ultimate target, when we were building and modelling the house, we’d shot for a modestly ambitious goal of 0.8 ACH (again my prior post for the background information). I was only aware of a handful of houses that had been able to reach 0.6 ACH in Canada and much less that had ever done so in Saskatchewan. Anyways, when we’d originally run the Blower Door Test in 2015 we’d ended up hitting 0.72 ACH – meeting our goal. We were happy with that.

Still after we’d tested, Howard, who ran the test, speculated the results were perhaps not entirely accurate and he’d suggested running the tests again. But one thing led to another and we got busy, life happened and we sort of forgot about doing it again…

That is until this past Spring. I’d written in my last post about having issues with 2 of our exterior doors needing to be replaced due to bowing of the frames (increasing leakiness). When we replaced these we’d also decided to add cam locks to all of the doors to increase the seal and prevent any potential bowing in the future. Surprisingly, we had noticed almost immediate improvement in the comfort of the house. It’s strange but when you have such an energy efficient house any slight deviations from it (that you may not ever perceive in a standard home) become blatantly obvious.

Also, which I did not write about, but around the same time I realized that the locking mechanism on one of our windows was not working at all – basically the window would close but it did not lock (also increasing leakiness). When the service technicians came out to replace the doors, they fixed the locking hardware of this window as well. We asked them to check all of the other windows when they were here and they recognized that a couple of the other windows were not totally centred (several of our windows had to be site glazed, i.e. glass installed in the frames on site as they were too big to ship with the glass in the frame). So they fixed those as well.

I started to think back to the Blower Door Test. I wondered how much tighter our house was now that these issues were fixed? I mean, we actually noticed a perceptual physical change in the airtightness of the house. It felt different, better. How could that not correlate to some change in the actual air leakage values?

I contacted Howard again and asked if he would like to come repeat the test. I was cautiously optimistic about the potential to actually reach 0.6 ACH – the Passive House standard. But I was not going to hold my breath.


The testing took about an hour or so and I was anxiously awaiting the results.

Drum roll…

The air leakage rates for the house were:
Depressurization: 0.56 ACH
Pressurization: 0.61 ACH
Total: 0.58 ACH

That’s right. We hit the 0.6 ACH Passive House benchmark! Might have been 3 years in the making but we made it. I’m so pleased with the results.

Granted back in 2015, as I said, there really weren’t that many houses that hit the 0.6 ACH Passive House benchmark. There are more houses since that are reaching this standard and I couldn’t be happier that we can now put ourselves in that fairly elite category as well. It makes me very proud of the house and all the people that have worked to reach that level of efficiency.

Processed with VSCO with a6 preset


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