extruded polystyrene · 50mm
R 1.79
U 0.511 W/m²·K
extruded polystyrene, 50 mm — R 1.79
50 mm divided by a conductivity of 0.028 gives an R-value of 1.79. The U-value is 0.511, so a square metre leaks 10.23 W across a 20-degree difference.
Standards it meets
Not up to any of them yet
- Material
- extruded polystyrene
- Thickness
- 50 mm
- Thermal conductivity
- 0.028 W/m·K
- Thermal resistance
- 1.79 m²·K/W
- U-value
- 0.511 W/m²·K
- Heat lost per square metre
- 10.23 W
- As concrete
- 2.86 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 panel13 mm
- phenolic foam36 mm
- rigid polyurethane41 mm
- graphite EPS55 mm
- white EPS64 mm
- glass wool66 mm
- mineral wool71 mm
- cellulose75 mm
- timber232 mm
- plasterboard321 mm
- concrete2857 mm
Nearby cells
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
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 50 mm of extruded polystyrene?
1.79 — 50 mm in metres divided by a conductivity of 0.028.
Q. And the U-value?
0.511. That is 1.96 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 10.23 W across 20 degrees.
Q. How much concrete would match it?
2.86 metres.
Q. Which standards does it meet?
At 0.511 it does not clear any of them yet.