cellulose · 20mm
R 0.48
U 1.548 W/m²·K
cellulose, 20 mm — R 0.48
20 mm divided by a conductivity of 0.042 gives an R-value of 0.48. The U-value is 1.548, so a square metre leaks 30.95 W across a 20-degree difference.
Standards it meets
Not up to any of them yet
- Material
- cellulose
- Thickness
- 20 mm
- Thermal conductivity
- 0.042 W/m·K
- Thermal resistance
- 0.48 m²·K/W
- U-value
- 1.548 W/m²·K
- Heat lost per square metre
- 30.95 W
- As concrete
- 0.76 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 panel3 mm
- phenolic foam10 mm
- rigid polyurethane11 mm
- extruded polystyrene13 mm
- graphite EPS15 mm
- white EPS17 mm
- glass wool18 mm
- mineral wool19 mm
- timber62 mm
- plasterboard86 mm
- concrete762 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 20 mm of cellulose?
0.48 — 20 mm in metres divided by a conductivity of 0.042.
Q. And the U-value?
1.548. That is 0.65 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 30.95 W across 20 degrees.
Q. How much concrete would match it?
0.76 metres.
Q. Which standards does it meet?
At 1.548 it does not clear any of them yet.