Blown-in Insulation is one of the most common and cost-effective ways to insulate your home. Blown-in insulation works well because it fills in gaps. The R-value is measured by the depth of the insulation. R-30 is the minimum value required, which is generally equivalent to about 10 inches of insulation material. The insulation material is usually made of fiberglass or cellulose and both insulate about the same.