plasterboard · 250mm
R 1.39
U 0.641 W/m²·K
plasterboard, 250 mm — R 1.39
250 mm divided by a conductivity of 0.18 gives an R-value of 1.39. The U-value is 0.641, so a square metre leaks 12.83 W across a 20-degree difference.
Standards it meets
Not up to any of them yet
- Material
- plasterboard
- Thickness
- 250 mm
- Thermal conductivity
- 0.18 W/m·K
- Thermal resistance
- 1.39 m²·K/W
- U-value
- 0.641 W/m²·K
- Heat lost per square metre
- 12.83 W
- As concrete
- 2.22 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 panel10 mm
- phenolic foam28 mm
- rigid polyurethane32 mm
- extruded polystyrene39 mm
- graphite EPS43 mm
- white EPS50 mm
- glass wool51 mm
- mineral wool56 mm
- cellulose58 mm
- timber181 mm
- concrete2222 mm
Nearby cells
Same material, other thicknesses
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 250 mm of plasterboard?
1.39 — 250 mm in metres divided by a conductivity of 0.18.
Q. And the U-value?
0.641. That is 1.56 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 12.83 W across 20 degrees.
Q. How much concrete would match it?
2.22 metres.
Q. Which standards does it meet?
At 0.641 it does not clear any of them yet.