Choosing the right insulation

The main role of a thermal insulation product is to limit the transfer of heat between building walls.

An installation product is chosen on the basis of its thermal resistance, to ensure building energy efficiency. Thermal resistance quantifies the ability of the product to prevent the transmission of heat in summer and in winter. The higher the value, the less heat is transmitted.

Thermal resistance expresses insulation capability.

How is it calculated?

R = t/λ

R = thermal resistance

R expresses the insulation performance of the product. It depends simultaneously on the thickness and thermal conductivity of the product. The higher the R-value, the more insulation the product provides.

t = thickness

Insulation thickness.

λ Lambda = thermal conductivity

This value characterizes the ability of a material to transmit or prevent the transmission of heat. A good insulation must prevent the transmission. The lambda value depends on the nature of the material and its density. The lower the thermal conductivity value, the more effective the insulation material.

Thermal insulation products are also selected on the basis of the constraints they will be subjected to.

  • Mechanical performance checks may be necessary (vertical performance, compressive strength under load, etc.).
  • The insulation product may be installed internally, but also fitted to the exterior of buildings. Where this is the case, it is important to know how it behaves in the presence of water, in terms of water vapor transmission and its ability to resist biological proliferation (insects, fungi, microorganisms, etc.).

The thermal insulation product may also fulfil other functions, such as acoustic insulation and/or fire protection.

Insulation products are intended for long-term installation in buildings. They must therefore retain their properties over time.

A multi-criteria choice

A thermal insulation product provides insulation against heat and cold, but may also provide acoustic insulation and/or play a role in fire protection.

All the properties of an insulation product and their performance levels must therefore be considered in the context of the building and all applicable regulations.

A reliable choice

Insulation products are chosen on the basis of:

  • The lambda thermal conductivity of the material relative to its intrinsic properties
  • Product performance measurement reliability