The Importance of Insulation

Insulation is a method for slowing down the movement of heat. Heat seeks a cooler area so it flows out of your home in the winter and into your home in the summer. Insulation materials are similar to goose down in that they trap air in tiny pockets that restrict it from moving. Natural air movement is slowed down because the air can't move as freely. Insulation keeps your home cool in the summer and warm in the winter because it resists the flow of heat. Reducing the flow of heat by properly insulating your home results in using less energy for heating and cooling. It also works well as a sound absorber. In walls and ceilings, insulation can reduce the transmission of sound from one room to another or from the outside. Insulation increases the overall comfort of your home and adds to the resale value.

The amount of insulation you need to use depends on where you live. There are a variety of different kinds of insulation including fiber glass, mineral wool, cellulose, foam and cotton. The two most common for residential applications are fiber glass and cellulose. The way insulation is measured is by R-value. The "R" stands for resistance to heat flow and the higher the R-value, the greater the insulating power. The R-value is usually printed either on bags or labels by insulation manufacturers. It is also often printed on facings of fiber glass batts and rolls.

Make sure you know what R-value to use. You can get this from the builder or the local building code. This makes sure the product provides long-lasting thermal performance. The overall R-value is what counts, the R-value "per inch" is not important. Fiberglass insulation products come in R-values ranging from R-11 to R-38 for fiberglass batts and rolls. Fiberglass and rock and slag wool insulation can be blown in an attic to nearly any R-value. The more R-value alternatives provided, the greater the flexibility in meeting code energy requirements in your area.

To get the expected energy savings from insulation, you should make sure it will not deteriorate or settle over time. Fiberglass batts and rolls do not settle. Fiber glass and rock and slag wool loose-fill insulations may settle approximately 1-3 percent which means that there is pretty much no impact on the thermal performance of the insulation. Cellulose installation settles 20 percent and at a higher rate which means a significant loss of insulating effectiveness. The Insulation Contractors Association of America recommends that an additional 25 percent of thickness be added for cellulose insulation to compensate for the great loss of R-value.

Another factor to consider along with insulation is air infiltration. The Department of Energy estimates that about forty percent of a home's heat loss results from air infiltration. It most commonly occurs in parts of the home that are not insulated such as around windows, doors, fireplaces, HVAC ductwork and perimeter joints. It should be taken care of with the use of house wrap, proper caulking and sealing of band joists, sill plates, header plates and insulation around doors, windows, electrical outlets and other openings.

The most important thing to know is that proper installation is the key. Not only will proper installation save energy, heating and cooling costs, financial incentives are offered in many states for the purchase and installation of insulation.