The insulation in the attic area retards the warm or cool air from escaping the living area. One of the least expensive and easiest ways to reduce heating and cooling costs is to properly insulate the attic area. The inspector will identify the type of insulation used, its condition and how well it has been installed. Most modern construction is insulated with fiberglass rolls or bats. Up to twelve inches may be advised for maximum effectiveness. Some older types of insulation such as: rock wool, vermiculite, and cellulose can be ineffective and possibly a fire hazard. Many non-professionals will install insulation into the soffits or against the roof sheathing between the rafters. These types of installations will be pointed out because they can cause damage to the building materials.