glass wool · 100mm
R 2.7
U 0.348 W/m²·K
glass wool, 100 mm — R 2.7
100 mm divided by a conductivity of 0.037 gives an R-value of 2.7. The U-value is 0.348, so a square metre leaks 6.96 W across a 20-degree difference.
Standards it meets
Not up to any of them yet
- Material
- glass wool
- Thickness
- 100 mm
- Thermal conductivity
- 0.037 W/m·K
- Thermal resistance
- 2.7 m²·K/W
- U-value
- 0.348 W/m²·K
- Heat lost per square metre
- 6.96 W
- As concrete
- 4.32 m
Thickness for the same performance
This is the number that shows what insulation is worth. Matching 100 mm of XPS with concrete alone would take 5.7 metres of it. No one builds a wall like that — which is why a concrete building only gets warm once a thin layer of insulation is added.
- vacuum panel19 mm
- phenolic foam54 mm
- rigid polyurethane62 mm
- extruded polystyrene76 mm
- graphite EPS84 mm
- white EPS97 mm
- mineral wool108 mm
- cellulose114 mm
- timber351 mm
- plasterboard486 mm
- concrete4324 mm
Nearby cells
Same material, other thicknesses
Same thickness, other materials
How to read this
- Thermal resistance is the thickness in metres divided by the conductivity. Bigger is better.
- The U-value adds 0.17 of surface resistance and then flips the total. Smaller is better.
- Resistances add across layers, so a whole wall is the sum of its parts.
- Conductivity varies by product; the values here are typical for the material.
Frequently asked questions
Q. What is the R-value of 100 mm of glass wool?
2.7 — 100 mm in metres divided by a conductivity of 0.037.
Q. And the U-value?
0.348. That is 2.87 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 6.96 W across 20 degrees.
Q. How much concrete would match it?
4.32 metres.
Q. Which standards does it meet?
At 0.348 it does not clear any of them yet.