Windows are one of the most critical elements of a Passivhaus and any super-insulated energy home. The placement of the windows, the type of glazing, the type of coating, and the frames all have an integral role in how much or how little energy your home will use. But what most energy aficionados consider to be the most important is the frame. For us, the only real option was fiberglass. Most regular home install run of the mill vinyl, wood or metal – but these materials are simply highly inferior to fiberglass when it comes to energy performance.
“Fiberglass is created by pulling strands of glass through a heated die, resulting in a material that is strong, resilient, and suited to all weather conditions… Energy efficient frames have low conductivity that discourages the transfer of heat or cold into a building. Fiberglass has a much lower conductivity than metal options; simply placing a hand on a fiberglass frame compared to an aluminum frame in -20°C weather makes the difference very clear… Fiberglass is much less conducive to allowing cold temperatures to pass through the frame, thus helping to prevent condensation and loss of heat… Subjected to temperature extremes, windows must remain stable, with minimal expansion and contraction to keep an excellent seal. Considering that the bulk of a window is glass, what better material to surround it with than glass? Hence “Glass on Glass Advantage”. Composed of about 60% glass, fiberglass, like plate glass, has a very low rate of expansion and contraction. Fiberglass maintains an excellent seal with reduced movement relative to the plate glass. Superior stability also results in greater longevity, fewer seal failures, and better paint adhesion.” -Duxton windows
Although we are targeting Passivhaus performance levels for our house, actually purchasing “Passivhaus Certified” windows was simply far too cost prohibitive (~$90/sq.ft.) and must be shipped across the ocean from Germany (that is a big carbon footprint to overcome). There is one Passivhaus manufacturer of windows in Canada that I’m aware of called Northwin, but we didn’t pursue a quote from them, the only reason being is that no one around here had any experience with them, and from what I was told the cost was extreme. I had wanted a recommendation or at least a review from someone who had worked with, lived with or installed them before.
One of our friends had built a very energy efficient house and installed Fibertec windows out of Ontario. Although they were beautiful looking windows, they had nothing but problems with them (air leaking, condensation). My thought is that these windows, made in a warmer part of the country, were not designed with a cold prairie climate in mind (I have no evidence to prove this, mind you). As such we avoided any manufacturers outside of our climate zone. That basically let us with two fiberglass window manufacturers: Duxton windows and Accurate Dorwin, both from Winnipeg MB.
We knew people who’d either installed or worked with these windows before and each of them were happy with them. We received quotes from each of them and they were essentially equal (Duxton being $500 more). We ran the two windows through the energy modelling software and Duxton came out the winner. I’d also talked to a Passivhaus engineer who’d found that Duxton “performed very well in the PHPP.” My wife also liked the name “Duxton” better.
They are a pretty impressive and innovative company. We actually met the owner, Al Dueck, and had a drink with him at a Building Green conference a few weeks ago. The company has recently developed a quintuple paned window! Five panes with a rating of R20! Outrageous.
We ordered the windows way back in early May, before the ground had even been broke on the foundation. I’d been expecting this to be more than an ample amount of time for them to be fabricated and delivered. Well, I was wrong. So very wrong. Although I was told that they would be ready in 6 weeks, they weren’t actually delivered and installed for nearly 10 weeks. Fortunately for us, our builder and the subcontractors were willing to continue on and not wait.
We had everything coordinated when they confirmed at last that the windows and doors had been sent out. Our builder, received the shipment, unloaded them and said “WTF!” We were missing all of the doors and one of the largest windows. It was the end of the day and we scrambled to try and find out which of the three shipping companies may have lost them… but all of them confirmed, when I called them frantically, that they had received the same items. It wasn’t until the next day that we received a sheepish email from Duxton that they had “forgotten” to ship them. Oops!? What a headache.
Not only were we trying to coordinate the shipping, delivery, installation of the frames and smaller windows, but also the “site glazing” (6 of the windows were too large and heavy to be sent as a single piece, therefore the glass and frame were sent separately and had to be installed by another subcontractors). Basically there was a lot of pieces that had to fall into place. And none of them did. But after hours on the phone rescheduling everything, like most (kind of) things, in the end it worked out. The windows and doors arrived and were installed. And they look super sexy.