Insulation, heat transmission coefficients of the materials

Here is a summary page that lists the heat transfer coefficient Lambda current building materials.

Keywords: insulation, insulation, insulation materials, property, performance, performance, lambda, calculus, loss, loss, heat balance

All lambda are given in W / (mK)

Recall, calculating the thermal resistance of a paroie or wall:

Thermal resistance is given by the following formula:

R = e / lambda

With e = thickness of the wall in m
and lambda = heat loss coefficient of the materials used.

For the thermal resistances compound walls of several material layers aditionnent and for consitutes wall 2 1 and 2 materials:

R = total e1 / lambda1 + e2 / lambda2

therefore obtained in m2.K R / W which is not very significant, for against its opposite: W / m2.K to him is: the thermal transmission (ie: heat loss) of the wall degree of difference of T ° and m2.

A thermal resistance at least equal to 2 is considered a good standard insulation.

For example a well insulated wall:

- R = 3
- Outdoor temperature: 5 ° C
- Indoor temperature: 19 ° C

Conduction losses in the wall will therefore be equal to (19-5) * 1 / 3 4,66 = W per m2 surface of this wall.

This is a first simple approach to perform the heat balance of a house (other losses are convective air exchange, thermal bridges, carpentry etc ...).

Read more see Thermal regulation 2005: RT2005

lambda coefficients for common materials (click)

More:
- Habitat isolation Forum
- Folder comparison on natural and ecological insulation

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