Insulation is some material that is used to reduce the rate of heat transfer.
An R-Value is a calculated value used to measure and compare the insulative values of different materials.
R = Temperature Difference × Area × Time ÷ Heat Loss The temperature difference is measured in degrees Fahrenheit, area in square foot, time in hours, and heat loss in BTUs.
|Material, for each inch||R-Value|
|High density EPS foam||4|