Mike was willing to shed some light on how builders could tackle the challenge of selecting high-performance windows to fit the airtightness and comfort goals of a project and some of the barriers he sees in the adoption high-performance construction.
Just a note that the interview was edited for clarity and brevity.
Mike: It’s certainly an interesting time in the industry, especially for windows and doors, where we’re facing fairly rapid change in an industry that was pretty static for about a century before.
The biggest thing to happen to windows previously was going with double glazing instead of single and that that was about it.
Now we’re seeing rapid changes. We’re being introduced to completely new types of operating hardware, new advanced glazing systems, triple glazing and even vacuum insulated glazing or “hybrid” glazing units.
In numerical terms, you could say a window 40 years ago was about the same as it was 100 years ago. It had very limited protection from air, water, thermal loss, or solar heat. Within the last 40 years, we’re now producing windows that can basically be air and watertight, and the thermal values just keep rising.
There are not many products out there that can say they’re 10, 12, or 15 times better than they were 30 years ago, but windows certainly can.
Jessica: Yeah, there’s been a massive escalation in window technology. For some builders, there’s a question about how to evaluate the difference in high-performance windows. What would you recommend?
Mike: It’s kind of an unusual thing to look at because there are a lot of different perspectives that the builder can approach it from that will affect how they view it in the first place.
When you’re trying to introduce a higher performance product, some builders will want to see a kind of cost-benefit ratio. They’ll say, “okay, well, what’s the payback and in strict dollar-and-cents terms.”
There may not be that rapid of payback in some cases – especially if you’re only talking about one factor of the performance.
If you were to say, “based on your value, it saves X amount of energy, so it has on average maybe a seven to 10 years payback”. Well, that seems like a long time, but you’re also forgetting about the airtightness. That can be as much as 40% of the energy loss in a building. So, you can see a pretty significant increase to your energy savings when you combinemultiple factors – better insulating and more airtight windows – just like the rest of the building.
For me, the biggest factor to consider is the comfort and usability of the home for the property owners.Mike Cairns
If you have poorly performing windows, the surface of the window will get cold during winter and allow that cold to transfer in from the outside. And because hot air rises, cold air drops. It creates a natural convection current inside the room that makes the room feel drafty. It makes it feel colder and allows the heat to escape more rapidly through the exterior walls.
So, your home becomes very uncomfortable very quickly because of that loss of heat. And then on top of that, you’re going to feel cold radiating through the window.
[It’s not just a winter or heating-dominated climate problem.] In the summertime, you will have high levels of heat coming through the glass. So, what you end up with is a room where half of the room is uncomfortable, possibly even unusable, for a significant portion of the year.
If you’re in an area like the prairies where it’s very, very hot in the summer and very, very cold in the winter, you basically have rooms where you would not use the window side of the room except for, you know, a couple months in the spring and a couple of months in the fall. And square footage is expensive. You don’t want to be writing off your floor space just because poor performing products allow for discomfort. So, the payback on the high-performance products is much greater than just the strict savings of energy.
Jessica: Yeah, believe me, I just bought a house built in 1979 and the backroom is always 10-20 degrees colder or hotter.
Mike: Exactly! One of the beautiful things about some of the enhanced standards, like Passive House, is that it looks at things like the specific performance of the individual part. So, it would look at a window frame and say “that frame is performing so poorly that you’ll get condensation on it”. It doesn’t matter if the glass quality is high in that case.
The poorly performing frame will lead to condensation, which can lead to mold and rot. It’s an unhealthy indoor environment.
It’s nice to see those elements starting to become part of the common knowledge in the industry. Our grandparents had towels that they would stick at the bottom of the window to collect water through the winter.
We don’t need to live with that anymore.
Jessica: Can I circle back when a builder is trying to evaluate which high-performance window that they’re going for? What are some of the questions or criteria that they’re going to have to look for?
Mike: Builders need to know a little bit more about what the energy goal of their building is. So that they have an idea of what to ask about and what to ask for. A term like “high performance” is a very relative term. If you said, “I’m going to build a high-performance house,” what exactly does that mean?
If you hired an energy modeler, and said, “I want a house that performs 40% better than code standard”, in our area here (British Columbia), we have Step Code that gives builders levels (of energy use). The energy modeler would say, “40% better is Step Four.” We have this target to hit and they can advise much better.
You also have an airtightness target; you have an energy target; as a result of both, the average home that’s built to that step level is going to need a window that meets a certain level of performance. Now we can tailor that performance package to work without having to put too much extra effort into it.
At the end of the day, the better the performance of the window, the easier the rest of the home build is going to end up being. That’s the typically the lowest performing component in your building. Your walls can be R22 but your windows aren’t going to be, so you usually get the best bang for the buck if you’re spending money on the windows. You’re going to have the most appreciable difference in the end result.
Jessica: In some parts of the US or Canada, we don’t have airtightness building codes strictly defined. What do you say to a builder who says they want to build high performance, but they don’t have a numeric goal in mind?
Mike: My experience says that shooting for very high levels of performance is a better value than shooting for just a little bit better than the code.
Once you start making changes, like adding exterior insulation, adding more exterior insulation is not a big deal. Once you start shooting for some form of airtightness target to make your building more airtight, it doesn’t really cost any more to get it more airtight, it just takes a little more attention to the details.
Trying to build something that’s just a little bit better at the end of the day doesn’t make a whole ton of sense.
You can build to a very high level of performance without a huge uptick in cost. Because as you build to the higher levels of performance, you have more cost offsets. If you build airtight for example, you no longer need the same heating and cooling system, which helps bring the cost down while making it easier to build.
Jessica: Yeah, the risk of building to code or just slightly above actually opens you up a lot more problems, versus shooting for the stars and gives you a lot more room for success.
Mike: Yeah, of course. You know, there’s always a benefit to be gained as well. There’s an initial cost to be a leader, but it’s fantastic down the road when you’re the one that can say “I’m the first person in the area to build to this standard, and the first net-zero builder in the state or in the county. And I’ve been doing this for 10 years.”
So, when the code eventually elevates, and everybody else needs to build to it, now everyone’s going to talk to you first because you’re the guy that did it first.
Jessica: So, is there anything that you think people in the industry aren’t talking enough about?
Mike: This can go in a few different directions. I think, in general, not enough people are talking about airtightness in the right way. There’s still a lot of education to be done out there.
You know, we still, on a regular basis, face the old guard that says a house has got to breathe. There are still a lot of barriers to a breakdown in getting that knowledge out there that airtight doesn’t mean unhealthy. It means the opposite.
Jessica: How do you keep yourself up to date on all the information flying around?
Mike: What I do is I attend a lot of educational events on a pretty regular basis. I do a bit of research on the internet. I go through YouTube videos, I read literature that’s published. You know, there are a lot of different sources of information out there.
And some may be better than others. Some might be kind of contradictory. It’s nice to get a sort of balanced view from multiple sources and pull together what I think is maybe the best amalgamation of people’s knowledge.
Jessica: Okay. Would you mind naming some of the educational events or people that you follow things that you’ve recently read?
Mike: Well, there are a few great educators out there.
- Obviously, Joe Lstiburek with Building Science Corporation.
- RDH offers one of the best technical libraries out there (and for free).
- The National Research Council of Canada is a Federal organization that looks into a vast range of topics. You can search, or go down to “subject” and select form articles based on Walls, Moisture Performance, Acoustics, Air and Vapour Barriers, etc. There’s a lifetime’s worth of reading in there.
- Construction Connection teaches builders and developers how to build better and how to sell high performance and how to approach the topic of high performance. And they’re very knowledgeable guys.
- A lot of both national and local associations are fantastic. I pay attention to the local Homebuilders Association in Vancouver (HAVAN) and Passivehouse Canada.
- BC Housing is also great at putting valuable info out there – their mandate covers ensuring builders are doing good quality work, and ensuring occupant comfort
Jessica: With all these resources out there, what do you think is the barrier for the knowledge spreading?
Mike: Building Code is often a barrier because it sets the bottom rung of the ladder. There will always be people that want to work at the lowest possible price and people that want to pay the lowest possible price – and do things the easiest way. Anybody that’s competing and working at that level is going to be pushing down the dissemination of knowledge.
You know the old Maxim; you can’t teach an old dog new tricks. It’s not about age; it’s about learning a new way to do something. A lot of people are reluctant to try something new. Maybe because they’ve been burned in the past when they tried something out and it didn’t work. Maybe they just aren’t comfortable with the unfamiliar. If you spent your entire career building low performing homes it takes a lot of information to overcome the barrier to entry.
I see a lot of younger trade professionals adopting higher performance skills. Maybe everything is new to them anyway, so one other new thing is no big deal when you’re already learning everything from scratch.
Of course, there are some people in the industry who have been doing true high-performance buildings for a long time. We need to make sure we get their knowledge and experience passed down to the younger generation. Soon, I hope.
Jessica: What do you think we can do better in the high-performance industry about disseminating that information or making it more accessible?
Mike: I think just sharing the knowledge as much as possible. You know, don’t keep it proprietary.
Some guys will think “I have a competitive advantage because I’ve got this figured out” and then not share what they’ve learned along the way. At the end of the day, you’ll still be ahead of the other guy that’s just starting out. If you give them a couple of hints about how to do it right, it’s very much a rising tide that lifts all boats.
Jessica: Okay. So, increase everyone’s skills, better standards. Is there anything that we haven’t touched on? Or a message that you want to get out that we haven’t talked about?
Mike: Yeah, I’m hoping we continue to see more prefabricated products, more panelized products, and a lot more cooperation between different trades and different industries.
By working together and packaging our craft and skills together, everybody can help each other out and make sure that we can make this high-performance thing happen on a larger scale.
A big thank you to Mike Cairns for taking the time to talk with me.
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