The Department of Energy estimates that up to 45% of a home's energy loss can occur through the attic if the insulation is missing or isn't installed correctly. When installed properly, loose-fill insulation creates an energy-efficient home, lowers utility bills, and decreases fossil fuel burning and carbon dioxide emissions. To ensure energy and cost savings, builders need to follow manufacturers’ installation guidelines and check for the following:

• Correct R-value. A material’s insulative property is measured by R-value. Because each loose-fill insulation material has a different R-value, it’s necessary to install them at different densities in order to achieve an adequate level of insulation. Check the coverage chart for the bag count, density, and thickness needed for the desired R-value. Make sure the installer adjusts for the amount of settling that will occur over time and affect the installed R-value. Cellulose loses 20% of its R-value, so you should add 20% more in an attic during installation. The settling percentage of fiberglass and mineral wool is minimal and doesn’t affect thermal performance.
• No gaps or fluffing. If insulation isn’t installed at the right density, voids and gaps can form, lessening the R-value. When insulation is fluffed, it’s installed to minimum thickness but not to minimum weight requirements, allowing air and heat to pass through it. Before signing off on the attic insulation, check for gaps, insufficient depth, and insufficient density.
• Appropriate placement. Loose-fill insulation works well in attics because it’s the most cost-effective place to install a large amount of insulation. Make sure insulation is installed at the correct depth at end dams, and the top plates of the exterior walls are covered with insulation at the eaves. Check for continuous coverage and sufficient depth under ductwork, walkways, and mechanical platforms.
• Adequate drying. Make sure the loose-fill insulation has enough time to dry before the drywall is installed. For instance, if cellulose insulation is not completely dry, it will not meet R-value requirements.

Loose fill is an effective, environmentally friendly option for insulating attics, as long as it’s installed according to manufacturer’s specifications.

For more information about loose fill insulation, visit the Energy Efficiency and Renewable Energy website. More Best Practices® for insulating your homes can be found in BuildIQ University’s online training course, Insulation & Air Sealing.