Choosing Attic Insulation: A Homeowner’s Guide

Adding insulation to your attic is a great way to lower energy bills, and fall is a great time to do it. This guide can help you narrow your choices when choosing attic insulation, both in terms of insulation type and R-value (thermal resistance).

• Batt insulation is the most common type placed in attics. It’s usually made from fiberglass, and its thickness indicates its R-value.
• Blown-in insulation is made from recycled paper, known as cellulose, or loose fiberglass. Cellulose has a slightly higher R-value than fiberglass. The paper is finely shredded and treated with borates to increase its fire resistance and repel bugs, moisture and small animals. Loose insulation is suitable for both attics and walls.
• Foam insulation has some of the highest R-values inch for inch, so if your attic is small or hard to move around in, foam may be the answer. It’s more expensive, but it provides greater protection from temperature change. If you plan to use an attic as living space in the future, spraying foam on the underside of the roof sheathing represents a workable solution for insulation.
• Rigid foam insulation has a higher R-value than batt or blown-in. Rigid foam board is easy to lay between joists. It’s lightweight and usually doesn’t contain any volatile organic compounds that could irritate respiratory systems.
• Reflective insulation is another good choice when choosing attic insulation for our region. It reflects the sun’s heat away from the structure, and since we use more cooling than heating, choosing reflective or a combination of batt with a reflective film gives you better protection from the heat.