Where and how to install it. Tiny air pockets in insulating materials resist the transfer of heat, keeping it inside your home in cold weather, outside in warm. The ability to resist heat flow is measured in R (for resistance) values. The higher the R value, the greater the insulating power.
Buy insulation on the basis of R value, not thickness. Look for the R value printed on the insulation or its packaging. Types of insulation Batts (precut 4- or 8-foot lengths) or blankets (continuous rolls) of glass fiber or rock wool are sold with or without vapor-barrier facings. Loose fill of rock wool, glass fiber, vermiculite, or perlite is poured in place by hand. Loose fill and poly urea foam are blown into enclosed walls with special equipment. Rigid insulation is used for interior or exterior sheathing or around a foundation perimeter.
Insulate surfaces that separate living areas from unheated spaces or the Vent.
Where to insulate:
1. Unfinished attic floor, 2., 3., 4. Knee walls, Rafters, Collar beams in finished attic; 5. Walls in heated basement; 6. Floor over cold crawl space; 7. Exterior walls