In mid-November 2015, just before we moved into our new house, we were asked to be part of the Passive House Days tour (a worldwide weekend of awareness of Passive House and energy-efficient building). Well, not “officially” — we were asked to be a part of the tour by the event organizer in Saskatchewan, who was the Passive House (PH) consultant on what should become the first certified PH in Saskatchewan. Even though we did not build a PH, we did follow the standards as closely as I could justify. From the beginning we were not pursuing certification.
Although all of the visitors on the PH tour were very interested in our house, our process, and why we did the things we did, one question we got a lot was, “If you were following the Passive House standard, why not go all the way for certification?”
First, let’s back up a little bit. Indeed, the principles of a PH are second to none. From Passipedia: “Passivhaus is a building standard that is truly energy efficient, comfortable and affordable at the same time.” So simple. Brilliant even. I wanted to build a Passive House. Who wouldn’t?
BLOGS BY KENT EARLE
Adding It All Up, Part 1Blower-Door TestingInsulation, Air-Sealing, and a Solar ArraySoffits and Siding at the Blue Heron EcoHausPlacing the Concrete FloorsAdding Walls and RoofDealing With Really Bad WaterMaking an ICF FoundationLet Construction BeginPicking High-Performance WindowsHow Small Can We Go?Choosing a Superinsulated Wall SystemHeating a Superinsulated House in a Cold ClimateIs Passivhaus Right for a Cold Canadian Climate?
Strangely, if you visit the Canadian Passive House Institute (CanPHI) website, you’ll find that there are total of five projects that have received Canadian PH certification. If you look up the Passivhaus Institut’s Project Database, you’ll find that there are a grand total of 23 houses in all of Canada that have received PHI certification.
Why the discrepancy, you may ask? Why so few certified projects?
A standard designed for the German climate
This is a bit complicated, and took me a while to figure out. But here are the basics as I understand it: the Passivhaus standard was developed in Germany for German buildings in the German climate (obviously). However, when other builders in other countries tried to build a “Passivhaus” — in, say, the U.S., England, or Canada — they realized something profound: Hey… wait a second… I don’t live in Germany!
Maybe trying to build to the German Passivhaus standard in Minnesota or Saskatchewan is going to be really difficult? Maybe impossible? Or maybe possible but really expensive? Or maybe possible but only to produce a really uncomfortable building to actually live in?
Still, PH satellites started to spring up in most countries around the world. Slowly, Passive Houses, built to the German requirements, started to be built in other countries, with the first certified Canadian building being built in 2009. The uptake, however, was certainly neither rapid nor widespread. Why? Was it not as the Passivhaus Institut of Germany said — that these buildings are “truly energy-efficient, comfortable, and affordable”? Or is it just that we are too cheap or lazy or complacent to meet those strict German requirements elsewhere?
A few years ago, though, some people started to say, this is silly. Why are we following German standards and requirements for our buildings when we don’t actually live in Germany?
The German Passivhaus standard is as follows:
Space heat demand: Maximum of 15 kWh/m2 annually OR a peak demand of 10 w/m2.
Blower-door test result @ 50 Pa: Maximum of 0.6 ach.
Total primary energy demand: Maximum 120 kWh/m2 annually.
Simple enough, right? Hit these numbers using the PH planning software and your building can be certified as a PH. Where’s the problem?
The airtightness standard of 0.6 ach50 is strict but not impossible. There had been many houses built to this level of airtightness before PH came around. Rob Dumont’s own home in Saskatoon in 1992 tested at an awe-inspiring 0.47 ach50.
Jumping to the third requirement, the total primary energy demand of 120 kWh/m2âˆ™yr ensures essentially that you are not wasting energy or are at least using it wisely. It forces you to use energy-efficient lighting, appliances, and mechanical system components. I don’t think anyone can argue with that as being important to green building.
The space heating demand is the sticking point
The real problem, in my opinion, is the space heating demand of 15 kWh/m2âˆ™yr or a peak load of 10 W/m2. These numbers dictate the maximum amount of space heating allowed for each square meter of a building. Remember — this is based on a German climate.
In Germany, the number of heating degree days (HDD) is around 3,100 annually compared to more than 10,000 in Saskatoon. That means that the heating requirement in Saskatoon is three times that in Germany. Besides that, who really cares what your heating demand is? With the maximum energy demand of 120 kWh/m2âˆ™yr already stated, what difference does it make whether you use 50% of that to heat your house or 10% in terms of your overall efficiency? This is my real beef with PH and the one that most others working towards PH in countries that have climates other than a German one tend to struggle with, too.
Recently, the Passive House Institute U.S. (PHIUS) split off (or was banished — depending on what you read) from the German Passivhaus Institut. This allowed PHIUS to develop its own standard and specific requirements for climate zones in the U.S., and also allowed it to use North American calculation values instead of European. As a result, it is now easier — OK, let’s say, more attainable — to hit the PH targets for your Minneapolis house using a Minneapolis climate to calculate your requirements. Now that makes sense to me.
Sadly, the Canadian PH Institute has resisted following its American counterparts and has continued to align itself with the German requirements. Thus, it’s darn near impossible (practically) to meet the PH standard and become certified by the Canadian PH Institute.
There is a small loophole of sorts, though. A Canadian house can pursue certification via PHIUS, which has climate-specific standards for the northern states, where the climate is somewhat closer to our climate. Although the conversion is not exact, the space heating demand requirement for the northern U.S. is about 30 kWh/m2 annually (or double that allowed in the German standard). That’s better — but still, the maximum heating degree days in Saskatoon are more than any other place in the continental U.S. Nonetheless, there have been a few Passive Houses in Canada that have used the U.S. system to become certified (maybe 10 or 12).
I told you this was complicated…
Canada needs its own standard
Anyway, let’s try to bring this full circle, back to my original question: Why don’t we just build all new houses in Canada to the PH standard?
I hope that I have presented the argument that it may not be realistic to build a certified PH in Canada and follow the original edicts of the German Passivhaus Institut of “energy-efficient, comfortable, and affordable.”
From Part 1 of this series (see the first entry in the “Blogs by Kent Earle” sidebar), you may be able to see that there is a huge chasm between how most new homes in Canada are currently built (as a result of our pathetic building code allowing inefficient homes to be perpetuated) and the extremely difficult PH standards currently set in Canada.
Unfortunately, I think the CanPHI has done itself a disservice in not distancing itself from the German Passivhaus Institut. By not developing its own Canadian climate-specific standard for the unique climate zones of our country, which maybe (just maybe) one day could be adopted on a large nationwide scale.
Until such time that the CanPHI recognizes this and modifies its requirements appropriately and regionally, I doubt that PH will ever gain much more than a very small handful of faithful followers willing to spend, at all costs, to meet an arbitrary set of values developed on the other side of the world.
That being said, I do know that you can in fact build a house in Canada that is energy-efficient, comfortable, and affordable. Because that’s what we’ve done.
But it isn’t a Passive House.