Where do thermal bridges occur in a foam box?

Corners, lid channels and compressed surfaces warm or cool differently from the rest of the wall. A multi-point trial with the real load shows the local difference.

6 April 2026Updated 28 September 2026

Short answer

Thermal bridges form most often at thinned corners, hand recesses, the lid channel, surfaces compressed for labels and pressure points from the outer carton. You find them by monitoring product temperature at several points inside the box with the real load; an infrared image shows only the surface.

A thermal bridge is a spot that conducts heat more readily than the rest of the wall; in a foam box it is usually a thinned corner, a compressed area or an interrupted lid joint. The places to look are corners, hand recesses, the lid channel, surfaces compressed for labels and pressure points from the outer carton. A box that looks undamaged may have lost section under repeated compression.

The risk runs both ways. In a warm setting the weak point speeds up heat ingress; when a very cold source presses against it, a sensitive product can freeze locally. Average air temperature hides both extremes, so several representative points are monitored with the real load.

An infrared image helps, but it gives the apparent temperature of the surface and does not replace the product temperature record. If a deviation repeats at the same corner, look at the box section and the outside pressure first, then at the product.