Insulation·white EPS 300mm
white EPS · 300mm
R 8.33
U 0.118 W/m²·K

white EPS, 300 mm — R 8.33

300 mm divided by a conductivity of 0.036 gives an R-value of 8.33. The U-value is 0.118, so a square metre leaks 2.35 W across a 20-degree difference.

Standards it meets

  • passive house 0.15
  • Korean central-region wall 0.17
  • loose standard 0.30
Material
white EPS
Thickness
300 mm
Thermal conductivity
0.036 W/m·K
Thermal resistance
8.33 m²·K/W
U-value
0.118 W/m²·K
Heat lost per square metre
2.35 W
As concrete
13.33 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 panel58 mm
  • phenolic foam167 mm
  • rigid polyurethane192 mm
  • extruded polystyrene233 mm
  • graphite EPS258 mm
  • glass wool308 mm
  • mineral wool333 mm
  • cellulose350 mm
  • timber1083 mm
  • plasterboard1500 mm
  • concrete13333 mm

Nearby cells

white EPS 250mm
R 6.94
white EPS 400mm
R 11.11
graphite EPS 300mm
R 9.68
glass wool 300mm
R 8.11

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 300mm
R 42.86
phenolic foam 300mm
R 15
rigid polyurethane 300mm
R 13.04
extruded polystyrene 300mm
R 10.71
graphite EPS 300mm
R 9.68
white EPS 300mm
R 8.33
glass wool 300mm
R 8.11
mineral wool 300mm
R 7.5
cellulose 300mm
R 7.14
timber 300mm
R 2.31
plasterboard 300mm
R 1.67
concrete 300mm
R 0.19

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 300 mm of white EPS?

8.33 — 300 mm in metres divided by a conductivity of 0.036.

Q. And the U-value?

0.118. That is 8.5 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 2.35 W across 20 degrees.

Q. How much concrete would match it?

13.33 metres.

Q. Which standards does it meet?

At 0.118 it clears 3 of them.