How to Calculate Cellulose Insulation for Installation

You can maintain an energy-efficient home by insulating it with blown-in cellulose. Cellulose insulation typically is made of organic and recycled materials, such as newspapers, that are treated with flame retardants. To determine how much cellulose insulation you need, you must calculate the space to be insulated and the weight of the materials to be installed.

Things You'll Need

• Measuring tape
• Calculator
• R-value chart

Instructions

1. Measure the length and width of the area you are insulating. Then measure the depth of the area you need to fill. Inside a wall, the depth is the distance between the interior dry wall and exterior barrier.

2. Multiple the length times the width times the depth to determine the cubic footage of insulation required.

3. Calculate the weight of cellulose material you will need to fill the area. You'll need 2 to 3.5 pounds of cellulose per cubic foot depending on the brand of insulation and the type of area you're filling.

4. Determine the R-value required for the job. The R-value measures a material's ability to stop heat conduction. Roofs, walls, and floors have different R-values. Additionally, R-values differ depending on where you live. In areas with extreme climate changes, R-values are higher compared with those for moderate climates. Use a chart such as the one offered by Lowes or check with a local contractor or building inspector to determine the correct R-value for your space.

Tips & Warnings

• Contractors generally use fiberglass or cellulose insulation. Many people don't like fiberglass because of its carcinogenic properties. Cellulose doesn't have these properties, but it can increase a fire load because it is combustible. Even cellulose treated with fire retardant may give more fuel to a fire. Consult a contractor if you are concerned about cellulose insulation.

References

• Lowes: R-value table
• Energy Savers - R-value of Insulation
• Bob Villa: Blow-in-Blanket