An insulation R-value chart refers to a table that lists the levels of insulation recommended for different climates and for different areas in the home, according to Energy Star. Some R-value tables detail the specific R-values and other properties of different insulation types or building materials, illustrates Inspectapedia.
The R-value expresses a material's thermal performance, a measure of the insulation’s ability to resist heat, explains Energy Star. More specifically, the R-value is the calculated thermal resistance, which measures the insulating material's resistance to conductive heat flow, according to the U.S. Department of Energy. Insulation with a higher R-value is more resistant to heat flow and insulates more effectively.
The type, thickness and density of an insulation's material affect its R-value, explains the U.S. Department of Energy. The insulation's ability to provide its full rated R-value depends on its installation. Overall R-value varies by location of the building as well by manner of installation. Compressed insulation is less effective, as is insulation located in a wall, since heat is lost trough studs and building materials.
One uses an insulation R-value chart to find the amount of R-value needed for the type of insulation material, climate, type of heating system and part of the building to be insulated, notes the U.S. Department of Energy.