A heated ceiling tested with a thermal camera

What a thermal camera actually measures

It does not measure a performance, it measures the apparent temperature of a surface. That is already a great deal, provided you know what you are looking at: a thermal image depends on the emissivity of the material in view, on the angle, and on what is reflected in it.

What the image reveals on a heated ceiling

Evenness of heating first: a genuinely radiant ceiling appears uniform, whereas a strip system shows alternating zones. Then local defects, which give away a debonding, a badly connected element or a crushed air gap.

The aluminium trap

An aluminium surface has a very low emissivity, so what the camera mostly reads there is the reflection of its surroundings. Pointing a thermal camera at reflective insulation says nothing about its temperature, and a good many comparisons published online fall into that trap.

When to make the check

After a complete warm-up and before the ceiling is closed. An image taken ten minutes after switching on shows the inertia of the materials rather than how the system works.

A check of the same kind on the ePan Slim system is presented on the page devoted to it, and the method of a test bench on the comparison page.

What the client can ask for

A thermal image of the ceiling before closing up, included in the handover file. It costs nothing to produce during the works, it serves as proof of correct operation at handover, and it becomes the reference if an area behaves differently in a few years' time.