Insulation·extruded polystyrene 30mm
extruded polystyrene · 30mm
R 1.07
U 0.806 W/m²·K

extruded polystyrene, 30 mm — R 1.07

30 mm divided by a conductivity of 0.028 gives an R-value of 1.07. The U-value is 0.806, so a square metre leaks 16.11 W across a 20-degree difference.

Standards it meets

Not up to any of them yet

Material
extruded polystyrene
Thickness
30 mm
Thermal conductivity
0.028 W/m·K
Thermal resistance
1.07 m²·K/W
U-value
0.806 W/m²·K
Heat lost per square metre
16.11 W
As concrete
1.71 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 panel8 mm
  • phenolic foam21 mm
  • rigid polyurethane25 mm
  • graphite EPS33 mm
  • white EPS39 mm
  • glass wool40 mm
  • mineral wool43 mm
  • cellulose45 mm
  • timber139 mm
  • plasterboard193 mm
  • concrete1714 mm

Nearby cells

extruded polystyrene 20mm
R 0.71
extruded polystyrene 50mm
R 1.79
rigid polyurethane 30mm
R 1.3
graphite EPS 30mm
R 0.97

Same material, other thicknesses

extruded polystyrene 10mm
R 0.36
extruded polystyrene 20mm
R 0.71
extruded polystyrene 30mm
R 1.07
extruded polystyrene 50mm
R 1.79
extruded polystyrene 70mm
R 2.5
extruded polystyrene 100mm
R 3.57
extruded polystyrene 120mm
R 4.29
extruded polystyrene 150mm
R 5.36
extruded polystyrene 200mm
R 7.14
extruded polystyrene 250mm
R 8.93
extruded polystyrene 300mm
R 10.71
extruded polystyrene 400mm
R 14.29

Same thickness, other materials

vacuum panel 30mm
R 4.29
phenolic foam 30mm
R 1.5
rigid polyurethane 30mm
R 1.3
extruded polystyrene 30mm
R 1.07
graphite EPS 30mm
R 0.97
white EPS 30mm
R 0.83
glass wool 30mm
R 0.81
mineral wool 30mm
R 0.75
cellulose 30mm
R 0.71
timber 30mm
R 0.23
plasterboard 30mm
R 0.17
concrete 30mm
R 0.02

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 30 mm of extruded polystyrene?

1.07 — 30 mm in metres divided by a conductivity of 0.028.

Q. And the U-value?

0.806. That is 1.24 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 16.11 W across 20 degrees.

Q. How much concrete would match it?

1.71 metres.

Q. Which standards does it meet?

At 0.806 it does not clear any of them yet.