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What Is An R-value?

An R-value is a rating used to measure how well insulation can resist heat flow. The higher the R-value, the greater the insulation properties and the slower heat and cold flows through it. Because insulation with higher R-values is more energy-efficient, the colder the climate, the higher the required R-value.

Different areas of the home have different recommended R-values, depending on what materials are used and how much space is available for insulation. The table below shows the suggested R-values for homes.

The R-value you need will also depend on where you live. The map shows you what R-values you might need, based on your main home heating source.

   Area of Home Good Better Best
   Attics R-30 R-38 R-49
   Cathedral Ceilings R-19 R-30 R-38
   2x4 Walls R-13   R-15
   2x6 Walls R-19   R-21
   Floors R-19 R-25 R-30
   Crawl Spaces R-19 R-25 R-30
   Basement Walls R-11 R-13 R-15

*please consult your local building code for the minimum R-value required

- View R-value Map

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