Installation of windows in a passive house
In short - the installation of windows in a passive house consists of installing windows in the insulation layer, and not in the construction layer. So the window protrudes beyond the edge of the wall and "hangs" on special angles in the insulation layer. This avoids cooling down the construction layer (muru). In addition, care is taken to ensure adequate tightness, so as to eliminate air flow and water vapor migration.
However, this way of mounting the windows has its drawbacks - and these are usually the same - the price and accuracy of workmanship. Two factors influence the higher price:
a) angles for window installation. This may be surprising at first - but, anticipating the question, unfortunately, ordinary cheap angles will not work here. Professional installation requires such mounting of the windows, so that they can be regulated, leveling. Therefore, instead of the usual angles, specially developed systems are used for this purpose. Since they are a niche product, their price is right (despite the relatively low material value).
b) the difficulty of assembly. Because most of the teams installing windows are not completely prepared or convinced for this type of assembly - hence, analogously, The low supply of teams installing windows in the insulation layer results in a much higher price of such installation. Anyway, have to admit, that such a method of mounting requires even greater accuracy and precision than in the traditional method of mounting windows.
The problem with installing windows in the insulation layer is even greater in the case of large ones, and therefore heavy glazing used in passive houses (I wrote about the size of the windows in a passive house here).
Some investors who build passive buildings, especially multi-family, also beyond our western border, They consciously resign from this type of window installation, pointing to installation difficulties and high costs. In a single-family home, if we don't have big ones, heavy glazing, however, it is worth trying this method of assembly. However, if the cost is a significant barrier, we should at least limit the losses by partially insulating the window frame (the so-called. reveal) or isolating the window frame from the wall with additional insulation.