What is an R-value?
R-value measures how well insulation resists heat flow — the higher the R-value, the better the insulating performance.
Energy codes set minimum R-values for ceilings, walls, and floors that vary by climate zone, so colder regions require more insulation. R-value adds up across the layers of an assembly.
It's the standard way insulation is specified and compared; pair it with proper air sealing for real-world performance.
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