R Value

The R-value, also known as thermal insulance, is the temperature difference per unit heat flux, at steady state, between two defined surfaces of a material or construction that induces one unit of heat flux between the surfaces. The R-value is used for comparing insulating values of different materials, for the specific thickness of the material. The higher the R-value, the greater a material's insulating properties and the slower heat flows through it. The R-value does not include the interior and exterior air film coefficients. The R-value is the reciprocal of the U-factor.

Data Type: 
Decimal
Category: 
Unit of Measure: 
hr-ft2-F/Btu
Source: 
ASHRAE
Sector: 
Commercial, Residential, Multifamily
Term ID: c24d66cb-8f89-4dd6-8c3b-39542499a472
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