Going Greener with Attic Insulation

​Insulating your attic is one of the best ways to save money on your cooling and heating.  Here is a break down of some greener options when choosing insulation material for your attic . . .

Cellulose: If you want to go green, try cellulose insulation. Typically composed of 85 percent recycled newspaper and 15 percent natural fire-retardant borate, cellulose insulation is typically blown into the wall cavity as a loose fill. Cellulose insulation is environmentally friendly, has a price tag similar to fiberglass insulation and often has a higher R-value than fiberglass. The R-factor of cellulose insulation is approximately 3.8 per inch for material thickness, and it does not vary significantly over a wide range of densities. In an attic, 10 inches of cellulose insulation will have an R-Value of about R-38, regardless of the density of the material.

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Cotton: Cotton is another green option that you can install yourself. Cotton insulation is made from textile scraps, such as denim, and typically comes in batting form. Like cellulose, cotton insulation is treated with a fire-retardant chemical. A relatively low-chemical option, cotton is often used as an insulation by homeowners with health-related concerns. Cotton has a general R-value of 3-4 per inch for material thickness compared to fiberglass insulation batt with R-values ranging from 5 to 7 per inch. In  short, cotton insulation isn’t quite as efficient as fiberglass, an issue that is usually addressed by installing thicker batts or more layers. By increasing  the thickness of the layer of insulation you install you can easily raise R-values to comparable levels. The one downside of that, however, is cost.  Expect to pay 15-20% more for cotton than fiberglass insulation to achieve  similar insulation levels.

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Sheep’s Wool: If you want a low-chemical green option other than cotton, install sheep’s wool insulation. Sheep wool is a natural, sustainable, renewable, theoretically recyclable material and totally biodegradable that does not endanger the health of people or the environment. Formed into batting or loose fill, sheep’s wool is an environmentally friendly option. Sheep wool is naturally flame retardant because it has a high ignition temperature. Although it’s a relatively low-chemical insulation, sheep’s wool is typically treated to prevent moth infestation and mildew. Made solely from sheep wool fibres that are either mechanically held together or bonded using between 5% and 15% recycled polyester adhesive to form insulating batts. Sheep wool insulation is used for both thermal and acoustic insulating applications and has an R-value of thermal resistiance of approximately 3.5 to 3.8 per inch for material thickness.

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Remember: Most of the outside heat entering a home flows through the roof. Installing attic insulation along with radiant barrier foil will make your home far more energy efficient then just using one or the other. Installing both materials will keep your indoor environment cooler making your air conditioner work far less, and help save on your energy bills.

​Jon Scott