R'BULL reflective insulation, or passive cooling

What passive means

A passive device consumes nothing, is not controlled and does not break down. It acts by its presence alone, by changing the way energy crosses a surface. It is a precise technical category, not a figure of speech.

What that rules out

No production of cold, no setting, no control. A passive device does not adapt to demand and does not make up for a lack of output. It moves the starting point of the problem, it does not replace it.

What it gives in return

No bill, no maintenance, no wearing part and no refrigerant to top up. Over the life of a building, those four absences weigh heavily against active equipment that requires monitoring.

The two directions of transfer

A low emissivity face does not know which way the heat is going. It pushes back solar radiation in summer and holds back indoor radiation in winter, with no change of setting since there is none.

The condition to respect

A still air gap in front of the reflective face, closed around its edges. Without it, the product conducts heat instead of sending it back, and being passive does not compensate for careless fitting.

How to check it

An infrared thermometer, on a hot day, under the roof. The temperature difference between the exposed face and the inner face is measured in a few seconds and understood without any particular training.

Summer comfort is developed on the dedicated page, and the product on its data sheet.