Insulation·white EPS 250mm
white EPS · 250mm
R 6.94
U 0.141 W/m²·K

white EPS, 250 mm — R 6.94

250 mm divided by a conductivity of 0.036 gives an R-value of 6.94. The U-value is 0.141, so a square metre leaks 2.81 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
250 mm
Thermal conductivity
0.036 W/m·K
Thermal resistance
6.94 m²·K/W
U-value
0.141 W/m²·K
Heat lost per square metre
2.81 W
As concrete
11.11 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 panel49 mm
  • phenolic foam139 mm
  • rigid polyurethane160 mm
  • extruded polystyrene194 mm
  • graphite EPS215 mm
  • glass wool257 mm
  • mineral wool278 mm
  • cellulose292 mm
  • timber903 mm
  • plasterboard1250 mm
  • concrete11111 mm

Nearby cells

white EPS 200mm
R 5.56
white EPS 300mm
R 8.33
graphite EPS 250mm
R 8.06
glass wool 250mm
R 6.76

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 250mm
R 35.71
phenolic foam 250mm
R 12.5
rigid polyurethane 250mm
R 10.87
extruded polystyrene 250mm
R 8.93
graphite EPS 250mm
R 8.06
white EPS 250mm
R 6.94
glass wool 250mm
R 6.76
mineral wool 250mm
R 6.25
cellulose 250mm
R 5.95
timber 250mm
R 1.92
plasterboard 250mm
R 1.39
concrete 250mm
R 0.16

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 250 mm of white EPS?

6.94 — 250 mm in metres divided by a conductivity of 0.036.

Q. And the U-value?

0.141. That is 7.11 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 2.81 W across 20 degrees.

Q. How much concrete would match it?

11.11 metres.

Q. Which standards does it meet?

At 0.141 it clears 3 of them.