Should You Insulate the Attic Floor and Rafters?

How Insulation Works in the Attic

• The value of insulation cannot be underrated. Insulation provides a resistance to heat flow in a home and traps needed heat or cooled air within an insulated, enveloped space. The attic and the roof of the home are the prime sources of energy leaks in a home, as heat naturally rises and cold air naturally moves towards the hot. To keep the interior space at the desired temperatures, install insulation in the attic.

Energy Savings, Incentives and Rebates

• By installing insulation in your attic, you can reduce your energy bill up to 20 percent or more. Well-insulated homes with dual-pane windows take less energy to heat or cool and retain their set temperatures longer than homes without attic insulation. Many states and utility companies provide tax incentives and rebates to people who install insulation in the attic. Check with your state or public utility for further information.

Attic Floor or Rafters

• If you have an attic floor with joists, simply insulate between the attic joists. Ensure that insulation is installed into the walls of the attic as well. If you place insulation between the attic floor joists, you are not required to place insulation between the attic rafters. For an easy install, use blown-in insulation for the attic. In an attic without a floor, blown-in insulation fills the space between the joists and gets all over the place, making the room look like someone dumped a load of cotton balls in the attic. In homes with cathedral ceilings, apply rigid board insulation instead.

Recommended Levels of Insulation

• Attics take more insulation than exterior walls do because most of the home's energy escapes through the roof. For instance, if the walls of a home are insulated with R-13, then install R-30 in the attic. For walls that are insulated with R-19, R-38 goes into the attic. These figures vary, based upon the region's climate where the home is built.