mineral wool · 120mm
R 3
U 0.315 W/m²·K
mineral wool, 120 mm — R 3
120 mm divided by a conductivity of 0.04 gives an R-value of 3. The U-value is 0.315, so a square metre leaks 6.31 W across a 20-degree difference.
Standards it meets
Not up to any of them yet
- Material
- mineral wool
- Thickness
- 120 mm
- Thermal conductivity
- 0.04 W/m·K
- Thermal resistance
- 3 m²·K/W
- U-value
- 0.315 W/m²·K
- Heat lost per square metre
- 6.31 W
- As concrete
- 4.8 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 panel21 mm
- phenolic foam60 mm
- rigid polyurethane69 mm
- extruded polystyrene84 mm
- graphite EPS93 mm
- white EPS108 mm
- glass wool111 mm
- cellulose126 mm
- timber390 mm
- plasterboard540 mm
- concrete4800 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 120 mm of mineral wool?
3 — 120 mm in metres divided by a conductivity of 0.04.
Q. And the U-value?
0.315. That is 3.17 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 6.31 W across 20 degrees.
Q. How much concrete would match it?
4.8 metres.
Q. Which standards does it meet?
At 0.315 it does not clear any of them yet.