Common House Insulators

Batts or Blankets

• Rolls of insulation batts, or blankets, are the most common insulation material, according to the U.S. Department of Energy. They are simpler for you to install than other types of insulation, because you roll them out and cut them to fit. They are usually made of fiberglass, but some are made of rock wool or cotton. The fluffy nature of this type of insulation contributes to its ability to insulate. Batt insulation is available in a wide range of insulating R-values, from 2.9 to 4.3 per inch of thickness. If you are considering additional insulation to go over existing batts in your attic, choose unfaced batts, that is, batts without a facing of kraft paper, vinyl or foil-kraft paper attached.

Blown-in or Loose

• Blown-in insulation has benefits and drawbacks. It fills spaces between joists or studs more completely than some batts, but installing the insulation in large areas requires a special blower machine. Loose insulation is made of cellulose, fiberglass or rock wool. It's wise to have an experienced professional perform the installation. Spreading consistently by hand is difficult, and blower machines are expensive. Installed unevenly, it loses R-value. Some contractors are skilled at filling walls with blown-in insulation by drilling holes in the walls and filling the cavities.

Sprayed-In Foam

• Sprayed-in foam is an extremely efficient insulation, but it requires special chemicals and equipment. It is easier to install in new construction or areas where the spaces in the walls are fully-exposed. Thin, liquid foam is sprayed evenly into the wall or floor cavity with a hose. Within moments, the foam expands, filling even the smallest spaces in the cavities. After it is dry, excess foam is trimmed back to the floor joists or wall studs.

Rigid Foam Board

• Rigid foam board insulation's R-value is not as high as that of other types, but it does have its place. It is usually installed on the exterior, under siding, where it helps block heat transfer and drafts. Interior installation is also possible. Attaching it to solid basement walls helps insulate where installing other insulation materials isn't feasible. Many locations require adding a fire-resistant barrier if foam board is used indoors, so check your local code.