Overall R-Value / U-Value

Series area-normalized resistance R″ = Σ(L/k) + surface resistances. U = 1/R″. Not parallel paths.

Thermal & HVAC

Series area-normalized resistance R″ = Σ(L/k) + surface resistances. U = 1/R″. Not parallel paths.

App id: THERM-07. Reference version 1.0.

How to fill it

Fill the inputs. The tool shows the outputs.

On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.

Formula

R″ = Σ Lᵢ/kᵢ;  U = 1 / R″

Inputs

Name	Unit
Layer 1 thickness	`m`
Layer 1 k	`W/m-K`
Layer 2 thickness (optional)	`m`
Layer 2 k (optional)	`W/m-K`
Layer 3 thickness (optional)	`m`
Layer 3 k (optional)	`W/m-K`
Inside surface R″ (optional)	`m2-K/W`
Outside surface R″ (optional)	`m2-K/W`

Outputs

Name	Unit
R-value (R″) (hero result)	`m2-K/W`
U-value	`W/m2-K`

Diagnose

This tool does not attach diagnose observations.

Assumptions

Surface resistances are area-normalized (m²·K/W), not K/W.

Provenance

Series only. Leave unused layers blank.