thermal bridges illustration

Thermal bridges: the temperature factor fRsi

We continue our series of articles on the topic of thermal bridges: this time, we illustrate the fRsi value, which describes the thermal ”strenght” of a node under the point of view of internal surface temperatures. As we have explained in a previous article, the PSI value describes a higher or lower heat flow caused by a discontinuity in the thermal envelope - a thermal bridge - the fRsi factor is of primary importance for health and comfort considerations.

A Disastrous Case Study: How Replacing Windows Alone Can Lead to Mold

In our previous articles, we have cautioned that an energy retrofit should be approached with an integrated, whole-building approach, and by a professional with experience in calculating and simulating thermal envelopes. The photos below show what happened to one family's home when they decided to do an independent partial energy retrofit, without consulting a qualified professional. In this case, they decided to replace the old windows of their house with newer, high performance windows, hoping that they would be able to reduce their energy consumption.