Homefix: Cut heating bills by adding insulation

Dwight Barnett

Do you know how much you lose when heat goes through the roof? Some experts put the estimate as high as 45 percent of your heating bill, but that would be from an un-insulated attic. To reduce heat loss, you can add insulation if you are willing to get a little dirty.

First determine the type and amount of insulation you have. It's not a good idea to compress any of the loose-fill materials such as fiberglass or cellulose, but you can overlay with similar material. Use loose-fill fiberglass on fiberglass and cellulose on cellulose. If you have blankets of insulation known as batts, you can overlay with either additional batts or any of the loose-fill materials.

Remember, the more you compress any of the insulating materials mentioned, the more you will lose in the R-value of the insulation. The higher the R-value, the better the insulation is at reducing thermal transfer (the amount of heated air that passes through the insulation). Try to achieve an overall R-38 to R-49 rating with additional insulation. Batts are approximately R-3 to R-3.8 per inch of thickness. Loose-fill cellulose is R-3.13 to 3.7 per inch and loose-fill fiberglass is R-2.6 to R-3.0 per inch. You can find the R-value recommended for your region by going to:

Once you have decided on a material, make a plan and get help. If you choose one of the loose-fill materials, some of the big-box stores will either loan or rent the blower equipment necessary for installation. This is not a DIY project, and for safety reasons it should be a team effort.

1. Wear a long-sleeved shirt and use gloves, eye protection and dust masks for personal protection.

2. Use walk boards across the ceiling joists when working in the attic.

3. Do not leave the boards behind because this will reduce the R-value of your insulation.

4. Do not work near electrical wiring unless the power to the home has been turned off. Inspect the wiring and have a licensed electrician make repairs if the wiring has been damaged or if you can see where two or more wires have been spliced. Spliced wires must be inside a junction box.

5. Do not cover pot or canned light fixtures unless the lighting is approved for insulation.

6. Do not cover bathroom vent fans. Moisture from the fans will damage the insulation and the roof structure. Fans must be vented to the outside.

7. Do not cover the venting to the attic from the soffits (roof's overhang).

8. Do not allow the insulating materials to touch the underside of the roof's decking. Condensation can form, which would damage both the insulation and the roof decking.

9. Batts covered with paper or foil cannot be used to cover existing insulation. The paper or foil is a vapor barrier and will hold moisture next to the existing insulation. If you find existing insulation with the paper or foil exposed to the attic, simply peel the facing off the batts before adding additional insulation. Remove the flammable paper or foil from the attic space.

10. Make plans to insulate the attic access cover, door or stairs and, finally, add a self-adhesive foam seal for the attic access when the job is done.

Dwight Barnett is a certified master inspector. Contact him at C. Dwight Barnett, Evansville Courier & Press, P.O. Box 268, Evansville, Ind. 47702 or