How to Save Energy--Insulate Your Attic

Heat always flows from warmer spaces to colder spaces, and that's why you should insulate your attic. Good insulation keeps the heated air in your living area during the winter and prevents the hot air directly under your roof from migrating into your home during the summer. With poor insulation in the attic, your furnace and your air conditioner have to work harder. Follow these steps to insulate your attic.

Difficulty: Moderate

Instructions

Things You'll Need:

• Fiberglass batt insulation
• Dust mask, eye goggles, work gloves and hard hat
• Utility knife
• Baffles
• Plastic sheets
• Straight edge
• Stapler
• Tape measure

Understanding Insulation

1. Know the ratings system. Insulation is rated by R-value (resistance to heat flow), and the higher the R-value, the more resistant insulation is to heat flow. Choose a higher R-value for better insulation.

2. Research material options. R-values depend on the type of material itself as well as the thickness and density of the material. Common insulation choices for an attic are fiberglass batts or blankets or blown/loose-fill insulation (either fiberglass or cellulose). Fiberglass has an R-value of about 3 per inch, while cellulose has an R-value of about 4 per inch.
   

3. Check for air flow and adequate ventilation, a requirement for insulating an attic. Keep the insulation material over the living area of your home, and leave the soffit vents clear so air can circulate under your roof.

Insulating Your Attic With Fiberglass

4. Climb into your attic and measure how thick the insulation is. Calculate the current R-value based on that thickness. In northern states, it's recommended that attics have an R-value of 39, but any extra insulation will help improve your home's energy efficiency.

5. Determine the size of the area you want to cover to calculate how much insulation you need.

6. Fasten baffles in the areas where you don't want insulation to go. Baffles permit air to flow freely--for example, where roof rafters join with ceiling joints over the soffits.

7. If your attic doesn’t have any insulation now, install a vapor barrier first. Lay a sheet of 6 mil plastic between the floor joists and staple the plastic to the joists to hold it in place. Overlap the edges of the plastic to form a continuous layer that covers the area to be insulated.

8. Install insulation at the end of the attic away from your attic access. Measure and cut the fiberglass and tuck it firmly in between the ceiling joists. Don’t compact the insulation (that will decrease its insulating capability), just lay it in place.

9. Continue to cut and lay pieces in between the joists. Do not cover any lights or electrical fixtures that come through the ceiling. Also keep the insulation 3 to 4 inches away from any heating pipes.

10. Add a second layer of insulation to double your R-value. Lay it at right angles to the first layer.

Tips & Warnings

• Fiberglass insulation is commonly very itchy to work with. Wear a dust mask, goggles, long sleeves and work gloves to prevent contact with your skin.
• Move carefully in your attic. Step only on the ceiling joists, never on the "floor" itself. For better mobility, lay a plywood sheet across the joists to walk on.
• Don't remove any existing insulation. Its R-value will combine with the R-value of the new insulation you add.
• Add insulation and weather stripping to your attic access door to block air from migrating into your living space.
• Wear a hard hat when working in your attic. Banging your head on a roof joist can cause a serious injury.

[eclectic-one]

on 1/30/2009 Well written article, full of good information. Thanks for the insight.

[writer7]

on 10/28/2008 Great article. Thanks for the advice.

[iamageniuster]

on 10/27/2008 Awesome article. I'll give this a try. Thanks! 5 stars!