Insulation — Materials
Record thickness, the applicable λ or R, usable pack coverage and units. Check moisture and load conditions separately before choosing insulation.
Insulation
- EPS
- XPS
- PIR
- PUR
- mineral wool
- wood fibre
- cellulose
Thermal conductivity, density and dimensions vary by product. Enter verified product data in the calculator.
Product documentation
Use the manufacturer’s declaration or technical sheet for the exact product and intended use. Record the source, thickness, thermal conductivity, density, coverage and units where relevant. A material family is not a certified design value. Use comparable conditions when comparing products.
Lambda values for EPS, XPS and mineral woolSeparate insulation performance from pack coverage
These are hypothetical purchasing examples. Use the exact product, joint specification, pack contents and current supplier price for your order.
For the same product at 100 mm and an illustrative λ of 0.040 W/(m·K), layer R is 2.5 m²·K/W. Pack coverage changes the purchase quantity, not this resistance. For 42 m² and 5% allowance, plan 44.1 m²; eight packs of 5.76 m² supply 46.08 m², leaving 1.98 m² above the plan. Carry 44.1 m² with 0% additional allowance into a cost calculation. Check usable coverage for the exact thickness and installation system.
Related calculators and guides
- Layered thermal resistance
Nominal R and U for entered homogeneous layers.
- Insulation thickness calculator
Calculate insulation thickness in mm and inches from your target RSI or US R-value and product lambda, k-value or R per inch.
- R-value calculator: thickness and conductivity
Calculate insulation R-value from thickness and lambda, US k-value or R per inch. Enter mm, metres, inches or feet and compare RSI with US R.
- Insulation packs
Estimate insulation packs or pallets from net area or individual walls and openings. Use product coverage, whole layers and one allowance.
- Material purchase cost
Estimate whole packages, surplus and total purchase cost from your quantity and supplier price.