After covering thermal transmittance U and resistance R of opaque assemblies, and insulated glass, we now cover one of the most critical areas of the thermal envelope: window frames. Good windows are the cornerstone of a performing building for both comfort and energy efficiency, specially if it is a passive house.
Insulated glass units, IGU for short, have been around for a long time. These elements are of primary importance for the energy balance of highly performing buildings and passive houses: that is why we dedicate this article to the thermal transmittance of insulated glass.
With a short investigation, we add our contribution to what has been recently published by some Italian consumers and professionals associations. Although the example described in this article is purely Italian (and deeply so), we believe that the same situation with thermal paints is happening in other countries too. Here we try and evaluate how solid this products are, and whether or not they can be helpful, with an example of a thermal bridge.
We cover here two real examples of mold and condensation problems, with thermal insulation installed on the inside of existing masonry walls. In both cases, the solutions were chosen on an empirical basis, and turned out to be worse than the problems they were trying to mitigate.