What is the effect of a thermal bridge?
Heat seeks its way from the heated room to the outside. It follows the path of least resistance.
A thermal bridge is a localized area of the building envelope where a changed (usually increased) heat flow occurs compared to directly adjacent areas (assuming a temperature difference between inside and outside).
Effects of thermal bridges are:
-Changed, usually reduced internal surface temperatures; in the worst case this can lead to moisture penetration of building components and mould growth.
– Changed, usually increased heat losses
Both can be avoided in a passive house: The surface temperatures are then so high everywhere that there is no longer any critical moisture load – and the additional heat losses become negligible. If the thermal bridge losses are smaller than a limit value (set at 0.01 W/(mK)), the detail meets the criteria for “thermal bridge-free design”.