concrete · 120mm
R 0.08
U 4.082 W/m²·K
concrete, 120 mm — R 0.08
120 mm divided by a conductivity of 1.6 gives an R-value of 0.08. The U-value is 4.082, so a square metre leaks 81.63 W across a 20-degree difference.
Standards it meets
Not up to any of them yet
- Material
- concrete
- Thickness
- 120 mm
- Thermal conductivity
- 1.6 W/m·K
- Thermal resistance
- 0.08 m²·K/W
- U-value
- 4.082 W/m²·K
- Heat lost per square metre
- 81.63 W
- As concrete
- 0.12 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 panel1 mm
- phenolic foam2 mm
- rigid polyurethane2 mm
- extruded polystyrene2 mm
- graphite EPS2 mm
- white EPS3 mm
- glass wool3 mm
- mineral wool3 mm
- cellulose3 mm
- timber10 mm
- plasterboard14 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 concrete?
0.08 — 120 mm in metres divided by a conductivity of 1.6.
Q. And the U-value?
4.082. That is 0.25 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 81.63 W across 20 degrees.
Q. How much concrete would match it?
0.12 metres.
Q. Which standards does it meet?
At 4.082 it does not clear any of them yet.