Insulation·rigid polyurethane 20mm
rigid polyurethane · 20mm
R 0.87
U 0.962 W/m²·K

rigid polyurethane, 20 mm — R 0.87

20 mm divided by a conductivity of 0.023 gives an R-value of 0.87. The U-value is 0.962, so a square metre leaks 19.24 W across a 20-degree difference.

Standards it meets

Not up to any of them yet

Material
rigid polyurethane
Thickness
20 mm
Thermal conductivity
0.023 W/m·K
Thermal resistance
0.87 m²·K/W
U-value
0.962 W/m²·K
Heat lost per square metre
19.24 W
As concrete
1.39 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 panel6 mm
  • phenolic foam17 mm
  • extruded polystyrene24 mm
  • graphite EPS27 mm
  • white EPS31 mm
  • glass wool32 mm
  • mineral wool35 mm
  • cellulose37 mm
  • timber113 mm
  • plasterboard157 mm
  • concrete1391 mm

Nearby cells

rigid polyurethane 10mm
R 0.43
rigid polyurethane 30mm
R 1.3
phenolic foam 20mm
R 1
extruded polystyrene 20mm
R 0.71

Same material, other thicknesses

rigid polyurethane 10mm
R 0.43
rigid polyurethane 20mm
R 0.87
rigid polyurethane 30mm
R 1.3
rigid polyurethane 50mm
R 2.17
rigid polyurethane 70mm
R 3.04
rigid polyurethane 100mm
R 4.35
rigid polyurethane 120mm
R 5.22
rigid polyurethane 150mm
R 6.52
rigid polyurethane 200mm
R 8.7
rigid polyurethane 250mm
R 10.87
rigid polyurethane 300mm
R 13.04
rigid polyurethane 400mm
R 17.39

Same thickness, other materials

vacuum panel 20mm
R 2.86
phenolic foam 20mm
R 1
rigid polyurethane 20mm
R 0.87
extruded polystyrene 20mm
R 0.71
graphite EPS 20mm
R 0.65
white EPS 20mm
R 0.56
glass wool 20mm
R 0.54
mineral wool 20mm
R 0.5
cellulose 20mm
R 0.48
timber 20mm
R 0.15
plasterboard 20mm
R 0.11
concrete 20mm
R 0.01

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 20 mm of rigid polyurethane?

0.87 — 20 mm in metres divided by a conductivity of 0.023.

Q. And the U-value?

0.962. That is 1.04 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 19.24 W across 20 degrees.

Q. How much concrete would match it?

1.39 metres.

Q. Which standards does it meet?

At 0.962 it does not clear any of them yet.