Envelope performance

A U-Value and R-Value Builder for Comparing Envelope Options

Compare thermal resistance and transmittance through homogeneous or parallel-path envelope assemblies in SI and US customary units.

What U-Value & R-Value Builder does

Layer and path resistances with SI and US U- and R-value results.

How it fits into the workflow

  1. Define the assembly paths, layers, thicknesses and conductivities.
  2. Check path fractions and any justified correction entered by the user.
  3. Review U-value, U-factor and R-value results with the exposed method trace.

Where it can save time

Layer libraries, reversible units and a visible calculation trace make early assembly comparisons faster and easier to review than isolated calculator results. Parallel paths can be tested without hiding the area fractions behind a single unexplained value.

Compliance and professional limits

The method can support early work informed by ISO 6946 and Approved Document L, but it is not a complete regulatory assessment. Repeating bridges, fasteners, cavities, ground contact and project-specific corrections may require a different verified method.

Professional boundary: Repeating bridges, fasteners, cavities, ground contact and other standard-specific corrections require an appropriate verified method.

Official and standards references

In summary

U-Value & R-Value Builder is most useful when its saved output remains connected to the project decision and is reviewed within the limits described above.