An Introduction to Insulation

What Is Insulation?

Thermal insulation in buildings is an important factor to achieving thermal comfort for its occupants. Insulation reduces unwanted heat loss or gain and can decrease the energy demands of heating and cooling systems. The effectiveness of insulation is commonly evaluated by its R-value. For attics, it is recommended that it should be at least R-49 in this climate.

Benefits of Insulation

According to the U.S. Department of Energy, 50% to 70% of the energy used in homes is for heating or cooling activities. By properly insulating your home, you can create a more comfortable and consistent indoor climate while significantly improving your home’s energy efficiency. Insulating your roof or ceiling will help keep your home at a pleasant temperature while saving you money on energy bills. With energy costs on the rise, maximizing the energy efficiency of your home is more important than ever before.

What Are the Priorities for Insulation?
insulationHeat constantly travels towards cooler areas. Insulation works by decreasing the amount of heat entering from outside when it’s hot, and trapping warmth inside when it’s cold outside. The highest proportion of heat transfer occurs through the roof and ceiling, so it’s most important to insulate in those areas.

Most homes are insulated in the attic and any floors that are located above unfinished basements or crawl spaces. The most effective places to add insulation to older homes are exterior walls, attics, basements and crawl spaces.

Types of Insulation

Blow-in Insulation

Blow-in insulation, or loose fill insulation, is usually made of fiberglass or cellulose (recycled paper fiber). It is blown or sprayed into place with pneumatic equipment and is ideal for use in hard-to-reach areas, such as attics. It can also be used to fill wall cavities and can be installed over existing insulation.

Densely packed cellulose

Densely packed cellulose and fiberglass are the favored methods if insulating walls and other closed cavities in existing dwellings. Dense packing is also gaining favor in new construction. Dense-pack methods have the advantages of preventing insulation from settling, completely filling the cavities, consistent insulating val-ues, and the ability to slow airflow.


Batts are precut sections of fiberglass or rock wool insulation that are designed for easy handling and use between framing, such as studs and joists. Batts are available either with or without paper or aluminum foil facing. They can be used in floors, walls, attics and ceilings.

Spray Foam

Latex or polyurethane spray foam is sprayed into place with a spray can or specially designed equipment. Spray foam can be used to fill small gaps and cracks and is ideal for sealing around doors, windows and vents. Special equipment is used to apply foam to larger areas. Spray foam sets quickly and can be trimmed, painted or stained.

Vapor Barriers

House wraps and kraft-faced insulation are examples of vapor barriers that help control the amount of moisture that passes through the insulation. Vapor barriers are most commonly used when framing the exterior walls of a house.