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.
In the fifth and last installment of The Passive House Build, Steve Baczek writes about “Installing High-Performance Windows.” 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. 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.
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.…