Calculate the amount of insulation by dividing your attic's square footage by the coverage area of the insulation package you plan to purchase.
R21 insulation is approximately 5.5 inches thick. This type of insulation is often used in walls and provides a higher R-value compared to standard insulation options, contributing to improved energy efficiency and thermal comfort in residential and commercial buildings.
The main difference is in installation; batt insulation comes in pre-cut pieces, while roll insulation is installed by rolling it out between ceiling joists.