What is insulation?
Insulation is a material that slows or inhibits heat flow from one area to another. It can take many forms. A common type is fiberglass or mineral wool (aka rock wool and sag wool). Another is cellulose insulation, an environmentally friendly option that is blown into wall cavities. Sprayed foam insulation is a go-to option if you need to add insulation to existing areas and around obstructions.