Insulation Thickness Comparison Calculator
Compare two insulation thickness options using thickness, thermal conductivity, area, density and material cost assumptions. See the trade-off between added material and estimated thermal resistance.
Project and option inputs
Thickness comparison
What changes when insulation gets thicker?
For a homogeneous insulation layer with constant conductivity, thermal resistance increases with thickness. Material volume also increases linearly with thickness for the same surface area.
Estimated material R = thickness ÷ conductivity
Material cost = volume × price per m³
Worked comparison
For 200 m², increasing thickness from 100 mm to 150 mm increases insulation volume by 50%. If conductivity stays the same, the idealized material-layer R-value also increases by 50%.
Why conductivity matters
Two products at the same thickness can have different thermal resistance because their conductivity differs. That is why thickness alone is not enough for a meaningful product comparison.
What this comparison cannot tell you
A building assembly includes framing, fasteners, joints, air layers, thermal bridges and other materials. The calculated material R-value therefore should not be treated as the whole-wall or whole-roof thermal performance.
Decision guidance
Use the comparison to understand the quantity and material-cost impact of changing thickness. Use the project specification, climate design, assembly calculation and applicable requirements to select the actual insulation thickness.
Frequently Asked Questions
Does thicker insulation always mean higher R?
For the same homogeneous material, idealized material R increases with thickness.
Does thicker insulation always cost more?
For equal price per volume, yes.
Can two materials have the same R at different thicknesses?
Yes, when their conductivity values differ.
Is this a code-compliance calculator?
No.