Insulation·white EPS 100mm
white EPS · 100mm
R 2.78
U 0.339 W/m²·K

white EPS, 100 mm — R 2.78

100 mm divided by a conductivity of 0.036 gives an R-value of 2.78. The U-value is 0.339, so a square metre leaks 6.78 W across a 20-degree difference.

Standards it meets

Not up to any of them yet

Material
white EPS
Thickness
100 mm
Thermal conductivity
0.036 W/m·K
Thermal resistance
2.78 m²·K/W
U-value
0.339 W/m²·K
Heat lost per square metre
6.78 W
As concrete
4.44 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 foam56 mm
  • rigid polyurethane64 mm
  • extruded polystyrene78 mm
  • graphite EPS86 mm
  • glass wool103 mm
  • mineral wool111 mm
  • cellulose117 mm
  • timber361 mm
  • plasterboard500 mm
  • concrete4444 mm

Nearby cells

white EPS 70mm
R 1.94
white EPS 120mm
R 3.33
graphite EPS 100mm
R 3.23
glass wool 100mm
R 2.7

Same material, other thicknesses

white EPS 10mm
R 0.28
white EPS 20mm
R 0.56
white EPS 30mm
R 0.83
white EPS 50mm
R 1.39
white EPS 70mm
R 1.94
white EPS 100mm
R 2.78
white EPS 120mm
R 3.33
white EPS 150mm
R 4.17
white EPS 200mm
R 5.56
white EPS 250mm
R 6.94
white EPS 300mm
R 8.33
white EPS 400mm
R 11.11

Same thickness, other materials

vacuum panel 100mm
R 14.29
phenolic foam 100mm
R 5
rigid polyurethane 100mm
R 4.35
extruded polystyrene 100mm
R 3.57
graphite EPS 100mm
R 3.23
white EPS 100mm
R 2.78
glass wool 100mm
R 2.7
mineral wool 100mm
R 2.5
cellulose 100mm
R 2.38
timber 100mm
R 0.77
plasterboard 100mm
R 0.56
concrete 100mm
R 0.06

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 white EPS?

2.78 — 100 mm in metres divided by a conductivity of 0.036.

Q. And the U-value?

0.339. That is 2.95 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 6.78 W across 20 degrees.

Q. How much concrete would match it?

4.44 metres.

Q. Which standards does it meet?

At 0.339 it does not clear any of them yet.