What does thermal bridging refer to, and why is it important?

• A. A path for heat flow through more insulated parts; reducing thermal bridging worsens energy efficiency.
• B. A path for heat flow through less insulated parts; reducing thermal bridging improves energy efficiency.
• C. A method to increase heat storage within walls.
• D. A measure of how quickly a building gains heat from sunlight.

Answer: (D)

Thermal bridging happens when heat moves through parts of a building that conduct heat more easily than the surrounding insulation, such as studs, metal frames, or concrete. These higher-conductivity elements create a path that bypasses the insulated envelope, so heat can leak out in winter or seep in during summer despite good insulation elsewhere. Reducing these bridges is important because it lowers overall heat loss, improves energy efficiency, and helps prevent cold spots on interior surfaces that can lead to condensation and mold. The correct idea describes heat flow through less insulated parts and notes that cutting these bridges boosts energy efficiency. It’s not about heat storage or how fast a building gains heat from sunlight, which are different concepts.