Insulation Thickness for Target R-Value

Divide the target by the product's R-value per inch.

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Formula

Thickness = target R ÷ R per inch

Example calculation

R-50 with blown cellulose at R-3.6/in → 13.9 in.

Practical HVAC use

Attic top-ups and rigid foam selection.

Common mistakes

Ignoring settling for blown products.

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