R-value

{
  "id": "MLC-T-ENE-002040",
  "term": "R-value",
  "field": "Energy",
  "definition": "A measure of a material's resistance to heat flow in units of Fahrenheit degrees x hours x square feet per Btu. The higher the R-value of a material, the greater its insulating capability. The R-value of some insulating materials is 3.7 per inch for fiber glass and cellulose, 2.5 per inch for vermiculite, and more than 4 per inch for foam. All building materials have some R-value. For example, a 4-inch brick has an R-value of 0.8, and half-inch plywood has an R-value of 0.6. The table below converts the most common \"R\" values to inches. For other \"R\" values, divide the \"R\" value by 3 to get the number of inches.\n\n\"R\"-ValueInches\n\n31\n\n113.5\n\n196\n\n5218",
  "references": [
    "EIA Glossary"
  ],
  "url": "https://mlchart.com/terminology/energy/r-value/"
}