The Best Insulation Material for Sound & Heat

Fiberglass and Cellulose Insulation

Fiberglass is one of the most common types of insulation. Typically pink or yellow, it can come in batts, rolls or can be blown into a space. The best type of fiberglass insulation has vapor barriers. Rolls of fiberglass material might or might not have vapor barriers. Cellulose is a fiber made from recycled paper or scrap which is shredded and has chemicals added to it. It is both fire and insect resistant. Cellulose can be poured or blown into a space as loose fill or sprayed in wet by a machine.

Rock wool is made from molten rock. As an insulating material, it can be used as hollow brick or as concrete blocks. Synthetic insulation includes polystyrene foam that comes in the form of precut boards, polyurethane foam and expanding foam that comes in a spray. Foams can thoroughly seal even tiny areas in a house by expanding up to four times its original size on application .

Houle Insulation Inc. conducted a sound transmission class test on two walls to determine the resistance in a ceiling, wall and floors for sound passage. One was filled with fiberglass batts and the other with cellulose. They were compared to a noninsulated wall and to each other. The noninsulated wall scored 35, compared to the fiberglass-filled wall which scored as more soundproof at 29. The cellulose filled wall, however, scored the highest with a score of 44, indicating it was the best in reducing sound transmission. This appears to be due to the fact that fiberglass batts can leave gaps because they are cut and patched together while cellulose thoroughly fills spaces in ceilings or walls as it is sprayed in. It totally encases plumbing, wiring and other obstacles.

The best insulation to use often depends on the type of space you need to insulate. Use mineral wool quilt, blown cellulose fiber or blown-in mineral wool to insulate a roof or loft. Preformed split foam, mineral wool mat, foil/fiberglass insulation and vinyl-faced or ridged foam insulation are best for insulating pipe or ducts. To insulate walls, use cellulose which is blown in or fiberglass batts and rolls.