The armchair experts of the heated ceiling

The word exists

Ultracrepidarianism means holding forth with confidence on a subject in which one has no competence. The term comes from an ancient anecdote: a cobbler who, having rightly corrected the sandal in a painting, went on to judge the leg. The painter told him not to go beyond the shoe.

Why this subject attracts so much of it

Heating is a field where everyone has personal experience and where physical intuition seems to be enough. The sentence heat rises is true of air and false of radiation, but it has the appearance of common sense, which makes it very hard to correct.

How to recognise a solid argument

It separates conduction, convection and radiation instead of talking about heat in general. It states the conditions under which a measurement was taken. And it is willing to say what the system does not do, which is the best sign of seriousness in a technical account.

What we are willing to say

A radiant ceiling is not right everywhere. It needs a closed envelope to give its full effect. It does not replace properly sized insulation in a poorly performing home. And it is of no use in premises permanently open to the outside.

The only answer that convinces

No argument matches a room you walk into. That is why we keep a showroom with everything running, and why we would rather answer objections there than in writing.

The received ideas about heat rising are dealt with on the page devoted to that objection, and the showroom on the Ceilingo shop in Toulouse page.