An R-value represents a material’s insulating ability or its resistance to the flow of heat. In Virginia, the recommended R-value for attics is R-38 to R-60. As for the rest of the home, R-13 to R-15 is recommended for 2×4 walls, R-19 to R-21 is recommended for 2×6 walls, and floors or crawl spaces should receive R-25 to R-30. Different insulation materials offer different R-values per inch; your Tidewater technician can advise you on how best to achieve a certain R-value in a particular space.