U-Value Calculator
Build a wall section, get its thermal resistance + compliance.
Lay up an assembly layer by layer (insulation, masonry, air gap, etc.), and the tool reports the U-value, R-value, thermal mass, and whether it meets climate-aware targets.
U-Value Calculator
Runs in the browser — nothing to install.
Free account required. Create one.
| Standard | ISO 6946 |
| Input | Material library |
| Output | U / R-value |
Using it
Pick your workflow
Quick Check for a single element; Project Analysis for a full 3D envelope.
Add layers
Stack materials in the order they appear in your wall section — exterior to interior.
Set thicknesses
Adjust each layer's thickness; U/R-values recalculate live.
Load climate (optional)
Add an EPW to see climate-aware compliance targets.
Read the results
U-value, R-total, thermal mass, and pass/fail verdict appear on the right.
Tips
- Do — Order layers exterior → interior; the calculator uses surface resistances on the boundaries.
- Avoid — Forgetting air gaps or membranes — they affect R-value too.
U-Value Calculator
Runs in the browser — nothing to install.
Free account required. Create one.