The Passive House Build, Part Five: Installing High-Performance Windows
By far the weakest link in a Passive House, these imported windows must be installed perfectly.
Synopsis: In the fifth and last installment of The Passive House Build, Steve Baczek writes about “Installing High-Performance Windows.” Through a clear sequence of flashing, taping, and insulating, Baczek shows how to install these windows and hold up to a five-minute spray test without any signs of leaking.
Watch the videos and read the articles in this series (links below), then head on over to GreenBuildingAdvisor.com to join the conversation with the designer of this house, Architect Steve Baczek.
All articles in this series:
“The Passive House Build, Part One: Designed for Success” (FHB #240)
“The Passive House Build, Part Two: Air-Sealed Mudsill Assembly” (FHB #241)
“The Passive House Build, Part Three: Superinsulated Slab” (FHB #242)
“The Passive House Build, Part Four: Framing for Efficiency” (FHB #244)
“The Passive House Build, Part Five: Installing High-Performance Windows” (FHB #245)
All videos in this series:
The guiding principle of a Passive House is that its primary source of heat is the sun. Not only do you have to locate and size windows and doors to take advantage of that sunlight, but they have to be high-quality units capable of retaining that energy for times when the sun isn’t shining. That’s a tall order when you have 24 windows and three entry doors and your goal is a finished house with an air-leakage area that’s roughly the size of an index card.
Most of the windows and doors that are built to handle the stringent criteria required to meet Passive House standards come from Europe. That’s not because Americans can’t build them; rather, it’s because in Europe, there is a market that demands them.
For this job, Makrowin aluminum-clad, triple-glazed tilt-turn windows were used, with matching full-lite doors. Built in Slovakia, they are imported to the United States through a Massachusetts-based company called Yaro, which also provides the local product support necessary to bridge the gap between the builder and the distant European manufacturer.
In a typical American home, a window is fastened to the exterior sheathing through a nailing flange, and then the flange is sealed to the house’s weather barrier with flashing tape. As is typical with European windows, the units used on this project had no nailing flange and were instead screwed through their jambs and air-sealed to the Zip system sheathing that was used to build the deep rough openings. The windows were then air-sealed inside and out with a combination of tape and expanding foam.
Custom comes standard
The beauty of these Makrowin windows, and many other European windows like them, is that they are customized. Windows that are built to suit are great from a design standpoint because I’m able to get what I need and want out of the windows without much restriction. For example, if we decide during the energy-modeling stage that we need to let in a little more sun to make the energy calculations work, we don’t need to jump up to the next standard size; we can order the windows 1 in. wider or taller.
One thing to understand about high-performance windows and doors is that the frames are more costly than the insulated glazing units they hold. Therefore, larger windows are more cost-effective than smaller ones, which is not a bad bonus when windows make up 30% to 40% of the south wall of the house. Aside from function, these windows are just plain impressive in their fit, finish, and function. They close and latch with the heavy satisfaction of a bank vault and are perfectly balanced.
For more photos, illustrations, and details, click the View PDF button below: