Adding attic insulation is one of the most cost-effective home improvements you can make. But it is not part of many homeowners’ to-do lists because many homes already have some insulation in place. Unfortunately, the amount they have is not enough to take full advantage of the energy-saving capabilities of attic insulation.
How Do I Shop for Insulation?
Recommended insulation levels are based on climate. You can find the recommended R-values for your area by checking here. Insulation amounts are listed in R-values rather than inches. R-value indicates the material’s resistance to heat flow. The higher the number, the more resistance. Insulation products have their R-values listed on the product packaging so that you can compare one product with another.
You will see that the table lists R-values for both uninsulated attics and those that have a few inches of insulation already in place. Most homes will fall into the second category. In general, if you can see the tops of the ceiling joists, you need to add more insulation.
Do-It-Yourself or Do-It-for-Me?
Insulating an attic is one of those jobs that is trickier than it looks. Most homeowners fail to see the connection between insulating and air sealing, which is the plugging of openings that allow heated or air-conditioned air from the living area to escape to the attic. And there are a lot of openings, including those created by flues and chimneys, ducts, electrical and plumbing lines and recessed light fixtures. Many are hard to find, especially if there is some insulation in place. Insulation and air sealing work together to make an attic energy efficient, because each technique stops a different type of heat flow.
Attics that are uncluttered can be insulated with fiberglass or rock wool batts or blankets. But if there are obstructions or unusual angles, you may need a loose-fill material, such as blown-in fiberglass or cellulose. These require special equipment and should be left to a professional contractor to ensure even coverage and a consistent R-value throughout the space.
Another area that may require a pro’s expertise are recessed lights that have their housings in the attic. Old style “can” lights should not be covered with insulation. A contractor can set up safe ways to block the insulation as well as other alternatives.
Installers also need to consider ventilation. The attic space above the insulation should be ventilated so that any moisture laden air that makes its way from the living space to the attic is exhausted to the outside. There are a few ways to obtain adequate ventilation, including using a combination of ridge and soffit vents. But if the airflow is blocked because the insulation is installed incorrectly, condensation could occur, leading to wet insulation, which is worthless, or structural damage. Discuss your ventilation options with a qualified insulation contractor.
Installing attic insulation saves energy and money, but only if it is installed correctly.
Guest blog submitted by Fran Donegan, a DIY-for-the-home authority who writes on energy-saving tips for The Home Depot.