Musings on Passive House Standards and the Costs of New Home Construction, Part 2

If you have not read Part 1 yet, please go back and read it first. 

In mid-November of 2015, just prior to us moving into the house, we were asked to be apart of the Passive House Days tour (a world-wide weekend of awareness of Passive House and energy efficient building). Well, not “officially” – we were asked to be apart of the tour by the event organizer in Saskatchewan who is the Passive House (PH) consultant on what should become the first certified PH in the Saskatchewan. Even though we did not build a PH, we did follow their standards as closely as I could justify, but from the beginning we were not pursuing certification.

Although all of the visitors on the PH Days 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 PH standards 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 efficientcomfortable and affordable at the same time.” So simple. Brilliant even. I wanted to build a PH. Who wouldn’t?

Strangely, if you visit Canadian Passive House Institute (CanPHI) website there are total of 5 projects that have received Canadian PH certification. If you look up the PH Project Database there are a grand total of 23 houses in all of Canada that have received certification.

Why the discrepancy you may ask? Why so few certified projects?

This is a bit complicated and took me awhile to figure out. But here are the basics as I understand it: the Passivhaus standards were 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 USA, England, or Canada, they realized something profound: Hey… wait a second… I don’t live in Germany!

Maybe trying to build to German PH certified standards in Minnesota or Saskatchewan is going to be really difficult? Maybe impossible? Or maybe possible but really expensive? Or maybe possible but a really uncomfortable building to actually live in?

Still PH institute 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 not rapid nor widespread. Why? Was it not as the PH Institute of Germany said that these buildings are “truly energy efficientcomfortable and affordable”? Or is it just that we are too cheap and/or lazy and/or complacent to meet those strict German requirements elsewhere?

It seems like this is something that these PH satellites were struggling with as discussed herehere and here.

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 PH standards are as follows:

  1. Space Heat Demand: max. 15 kWh/m2a  OR  Heating load max. 10 W/m2
  2. Pressurization Test Result @ 50 Pa: max. 0.6 ACH
  3. Total Primary Energy Demand: max. 120 kWh/m2a

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 Pressurization Test for 0.6 ACH 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 ACH.

Jumping to the third requirement, the Total Primary Energy Demand of 120 kWh/m2a 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 systems. I don’t think anyone can argue with that as being important to green building.

The real problem though, in my opinion, is the Space Heating Demand of 15 kWh/m2a or heat load of 10 W/m2. These numbers dictate the maximum 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 3100 compared to over 10,000 HDD in Saskatoon. So that means there is over three times as much heating requirement in Saskatoon as compared to Germany. Besides that, who really cares what your heating demand is? With the maximum energy demand of 120 kWh/m2a 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 PH Institute in the USA (PHIUS) split off (or was banished – depending on what you read) from it’s affiliation with the German PHI. This allowed them to develop their own standards and specific requirements for climate zones in the USA (Minneapolis also has different heating needs compared to Miami) and also to use North American calculation values instead of European. As a result it is now easier – ok, let’s say, 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 been resistant to following their American counterparts and has continued to align itself with the German requirements. Thus making it darn near practically impossible to meet the PH standard and become certified by the Canadian PH Institute.

There is a small loop-hole of sorts though, a Canadian house can pursue certification via the PHIUS, which is somewhat closer to our climate in the northern States. Although the conversion is not exact, the Space Heating Demand requirement for the northern USA is about 30 kWh/m2a (or double that of the German standard maximum). That’s better, but still the maximum heating degree days in Saskatoon are more than any other place in continental USA. Nonetheless, there have been a few of PHs in Canada that have used the US system to become certified (ok, like maybe 10 or 12).

I told you this was complicated…

Anyway, let’s try to bring this full circle, back to my original question of 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 Institute of “energy efficientcomfortable and affordable.”

From Part 1 of this post, 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 perpetuate, 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 PH Institute. By not developing it’s own Canadian climate specific standards for the unique climate zones of our country, which maybe (just maybe) one day could be adopted on a large nation-wide scale.

Until such a time that the CanPHI recognizes this and modifies their 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 efficientcomfortable and affordable.

But it isn’t a Passive House. 

Because that’s what we’ve done.

house-snow

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