FAQ
Frequently asked questions
Practical answers about lambda, U-value, comparisons, and exports.
What is lambda?
Lambda is the thermal conductivity of a material in W/mK. Lower values usually mean better thermal insulation.
What is U-value?
U-value describes how much heat passes through a building element. Lower U-values indicate better thermal performance of the full assembly.
Can I compare materials?
Yes. Use the comparison section to choose a category, set a thickness, and compare materials by lambda and calculated thermal resistance.
Can I print or export the result?
Yes. You can print the result or export it to CSV, Excel, or PDF for reporting and documentation.
Does the calculator work for walls, roofs, and floors?
Yes. It is designed for layered assemblies such as external walls, flat roofs, pitched roofs, floors, and slabs.
Is the calculator suitable for quick design checks?
Yes. It is intended for fast concept-stage calculations, insulation comparison, and envelope optimisation before detailed design.
Can I switch thickness units?
Yes. You can switch between millimeters, centimeters, and inches, and the calculator keeps the values consistent.
Continue with the calculator and guides
Kalkulator ścian
Wall-specific landing page that feeds back into the main calculator.
Kalkulator dachów
Roof-specific landing page that feeds back into the main calculator.
Kalkulator podłóg
Floor-specific landing page that feeds back into the main calculator.
Porównanie izolacji
Osobna strona do porównywania izolacji i sprawdzania grubości docelowych.
U-value guide
Practical guide to lambda, R, and U with formulas and examples.
R-value vs U-value
A short guide to the difference between layer resistance and whole-assembly U-value.
Insulation thickness guide
Practical advice on choosing insulation thickness for real assemblies.