Energy efficiency of windows: the Uf value

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…

Thermal Transmittance U vs Th. Resistance R

To achieve thermal comfort and energy efficiency in buildings, a primary role is played by the thermal envelope: this is required to thermally decouple the indoor environment from the ever-changing external conditions, both in summer and in winter. The structures…

Insulation materials: discovering the lambda value

The lambda value of a material indicates its ability to transfer heat: this property is therefore very important in the design of highly performing buildings and passive houses. The information commonly available is unfortunately quite confusing: with this article, we'll…

Thermal bridges: the PSI value

For new builds as well as energy retrofits, worldwide the construction industry is shifting more and more towards zero energy buildings and Passive Houses. With the thermal envelope becoming more and more advanced, the correct evaluation of thermal bridges becomes…

What’s the “time constant” of a building?

Among the many parameters than play a role in the thermal behavior of a building, whether or not it is built to be a Passive House, the time constant is one of the least known ones. Nontheless, this parameter influences…