The “R” in R-Value stands for “resistance to heat transfer.” The higher the R-Value, the better the resistance to the heat we pay for in the winter months escaping through the attic, and the heat from hot summer getting in the home from the attic space. While there are numerous insulation types available on the market, the most common residential types in homes less than about 10-15 years old are:
- Loose fill fiberglass (2.5 R-Value per inch)
- Loose fill cellulose (3.2 R-Value per inch)
- Fiberglass batts (2.5 R-Value per inch)
Each type of insulation has an assigned R-Value per inch (shown above). To know what R-Value you currently have, you simply identify the type, measure the thickness, then multiply by the designated R-Value per inch. For example, if you have 9 inches of loose fill fiberglass insulation, you would multiply 9 x 2.5 which equals an R-Value of R-22.5.