Insulation Buying Guide

  • Getting Started

  • According to the U.S. Government, up to 20 percent of a home’s heating and cooling costs can be saved with insulation. Insulation slows the movement of warm air into cooler spaces. The comfort of the occupants is most important for insulating a home.

  • What to Consider

  • All openings in a home transfer warm/cold air during each season. Choosing Energy Star windows and doors will assist in slowing the movement of the air. These products have achieved the rating by submitting to a third-party test showing their ability to stop or minimize heat/cold transmission.

    An Energy Audit will identify the areas of the home with air leaks. An insulation contractor will use a blower door test, smoke test, or infra-red cameras to identify areas of the home through which air is leaking. provides instructions for homeowners to use for insulating their homes. If the project is beyond the ability of the homeowners, an insulation contractor may be hired to perform the tasks.

    Different areas of a structure will demand different means of providing the desired  result. Know and understand what is available and will provide the needed insulation.

    Various types of insulation are available and some can be used to fill spaces in older homes without too much injury to the original building. New construction is easier to insulate. Install insulation at the proper stage of construction.

    Building Codes have a major impact on the amount of insulation and the type.

    Building Science is a term that is used when designing an insulation plan. Knowing that roofs need ventilation, determines the thickness of the insulation for cathedral ceilings, for instance.

    Doing it Yourself is an option for re-insulating in many parts of the home, such as adding batts to the attic, or spray foam around pipes. But applying spray foam in walls of an addition or an existing wall will necessitate hiring an experienced professional insulation contractor.

  • Terms

  • R-Value measures the ability of the material to reduce heat flow. The higher the number, the slower the heat flow.

    Batts are pre-cut lengths of insulation manufactured to fit between studs, joists and rafters of a home. May be faced with paper or foil, or plain face.

    Rolls are continuous lengths of insulation produced in a variety of lengths and thicknesses to fit between studs, joists and rafters of a home. May be faced with paper or foil, or plain face.

    Blown-in insulation materials will be installed using machinery that will thrust the product using water or chemicals to reach into areas not easily accessed.

    Loose insulation comes in small pieces that are tossed or thrown into cavities such as attic floors.

    Rigid Panels are foam produced in various thicknesses to be attached to or between studs to slow the movement through structural elements. Can be cut to fit spaces.

    Spray foam insulation is available in easy-to-use cans to fill small cavities, such as around pipes, or is installed using machinery that sends the foam into larger spaces, such as between studs and rafters to fill the area and block air movement.

  • Types

  • Fiberglass consists of glass heated and spun —as in a cotton candy machine — to create fibers that are similar to wool. May include other raw materials and formed into batts or rolls with or without a paper or aluminum foil facing or left loose for blowing into spaces. Used commonly in exterior walls, attics, floors, ceilings and basements.  Contains 20 percent to 60 percent recycled content depending upon the manufacturer and the facility. The thickness of the batt will provide the added insulation value. Produced in thicknesses of 3.5 inches to 13 inches, fiberglass batts are rated at R-2.9 to R-3.8 per inch. Use gloves and wear a mask when dealing with fiberglass as the strands can cause irritation.

    Rock Wool or Mineral Wool (Slag Wool) are created by recycling iron ore from steel processing or from basalt that is heated and spun into fibers that are formed into batts, rolls or loose fill forms. Used in exterior walls, floors, ceilings, attics or basements. Depending upon the material and the manufacturer, they claim 10 percent to 15 percent, or 70 percent to 90 percent recycled content. Batts are rated for R-values of 3.3 to 4.2; loose fill rates R-2.2 to R-3.3.

    Cotton or Denim Batts are created with about 80 percent post-manufacturing fabrics treated with chemical to be fire retardant and mold resistant. The batts most frequently are blue due to their denim content and range from 2-inches thick to 8-inches thick with R-values ranging from 3.1 to 4 to be used in exterior walls (vapor barrier not included), attics, floors and crawl spaces. For attic floors, under floors or in crawl spaces, a mesh or wire support system will be necessary. Some manufacturers produce thinner material for use as water heater blankets, etc.

    Cellulose is a product of paper, usually recycled paper or wood with other materials to assist in making it fire resistant. Installed as batts, rolls, blankets, loose fill or blown in, cellulose is used in walls and attics; can be blown in over existing batts. Recycled content is 80 percent and higher, depending upon manufacturer. R-3.1 to R-3.8 per inch as blown-in.

    Spray Foam insulation is created from chemicals mixed on-site to form foam that is sprayed between wall studs and on attic floors — especially in areas not easily reached or filled with batts. A can of spray foam can be used to fill holes around pipes, or small trouble spots. The must be installed by professionals who have the appropriate chemicals, equipment and expertise.

        •  Open Cell foam uses water to spray the polyurethane foam into the cavities. It goes on as liquid and cures within minutes as a foam. The cell walls are often shared, so the plastic chemical portion is lighter and carbon dioxide is contained in the bubbles. As it ages the carbon dioxide depletes and at least 50 percent of the cells are open. This is a soft product and is a vapor retarder. It will dry out if exposed to blown rain or a roof leak. Claims up to R-3.5 to R-4 per inch of depth.

        •  Closed Cell foam uses a chemical as the spraying agent and traps the chemical within bubbles forming a harder structure. At least 90 percent of the bubbles have separate wall structures. As the foam ages, the chemical off-gases but the bubbles retain their structure. This is a moisture resistant product. Closed Cell foam claims up to an R-6 to R-6.5 (aged) per inch of depth.

    Rigid Foam Boards are plastic products and easy to install. Three variations of rigid foam boards are available:

        •  Expanded Polystyrene has an R-3.6 to 4.2 depending upon density. It is water permeable and is used for structural insulated panels and insulating concrete forms.

        •  Extruded Polystyrene is strong and waterproof, used often below grade as an insulation of foundations or as exterior wall sheathing. R-5 per inch due to its density makes it a good insulator.

        •  Polyisocyanurate has the highest R value among the rigid foam boards, but it will absorb moisture so is not used below grade. Produced with a foil facing, when taped at seams Polyiso can be installed on exterior walls as the facing will repel the water. R-6 to R-6.5 per inch.

  • Cost Considerations

  • Professional installation costs more than doing it yourself, but the professionally installed products, such as spray foam in walls and attics, may provide more energy savings over the long-term and a comfortable home.

    Homeowner installed batts and blankets in an attic will produce the desired results at a much lower cost.  Loose fill is easy to install and some blown-in insulation can be accomplished by proficient do-it-yourselfers

    Materials vary in costs with fiberglass the least expensive to purchase and to install. Sold by thicknesses, the materials will vary in cost by the amount of material needed to achieve the desired R-value Closed cell foam is the most expensive to install, and most often will be installed by a professional.

    Cost of Material should be compared to the R-value of the material, and the desired comfort of the occupants when making a decision on which material to choose.