Thermal insulation: three winning strategies from tennis

The first strategy: play before the rally

On a court, the best point is the one never contested. In insulation it is the same: the cheapest heat to manage is the heat that does not come in. Dealing with the roof and the glazing before sizing any equipment follows exactly that logic.

The second strategy: send back rather than absorb

A player who absorbs all the opponent's power eventually gives way. A surface that absorbs solar radiation releases it into the room afterwards. A low emissivity face sends that radiation back instead of storing it, and the problem no longer arises.

The third strategy: positioning

Being in the right place beats running fast. In insulation, the right place is continuity: the perimeter, the corners and the penetrations. A high performing product fitted with breaks gives a poorer result than a modest one fitted continuously.

What the metaphor does not say

A surface has no opponent. It obeys three known modes of transfer, conduction, convection and radiation, and each is dealt with by a different means. The image helps memory, it does not replace calculation.

The order of the three

It counts as much as their content. Act at the source, then send back, then ensure continuity. Reversing that order leads to equipping a house before protecting it, which costs more for a poorer result.

How to check your own game

An infrared thermometer and ten minutes. Measuring the temperature of a room's surfaces on a cold day, then on a hot one, shows precisely where the strategy falls short, with no particular technical skill.

Summer comfort is developed on the dedicated page, and airtightness on the airtightness page.