Performance metrics & physics
Thermal Bridging
Thermal bridging is the unwanted transfer of heat through conductive paths in a structure — for vehicles, this includes metal pillars, roof skin and door frames bypassing the insulating effect of glass.
In buildings, thermal bridging is a well-known issue: metal studs in walls conduct heat across the insulation. In vehicles the analogous effect is the metal body parts that conduct solar heat directly into the cabin.
Window film addresses the glass component of thermal bridging — the largest single source — but cannot prevent body-skin heating.
For Singapore vehicles, the combination of solar film plus reflective car shades (used when parked) plus a light-colour body produces the best overall thermal performance.