What does the term thermal bridging refer to?

Thermal bridging refers to the phenomenon where heat is conducted through building materials at a faster rate than surrounding materials, leading to increased heat loss or gain in a structure. When there is a thermal bridge, it generally involves materials that have a higher conductivity than the insulation around them, allowing heat to flow through these materials more quickly.

This can occur at various points in a building, such as at window frames, metal studs, or any location where there is a disruption in the building envelope. The effect of thermal bridging can significantly impact energy efficiency and comfort within a building, as it can create cold spots or increase the heating and cooling loads required to maintain a comfortable indoor environment.

The other options—heat loss through insulation, air leakage through windows, and moisture transfer through walls—do not accurately describe thermal bridging, as they focus on different issues related to building performance. Heat loss through insulation pertains to the overall efficiency of insulation materials, air leakage addresses gaps that allow uncontrolled airflow, and moisture transfer deals with the movement of moisture, rather than the rapid thermal conduction effects described by thermal bridging.