Courtesy of CertainTeed
Q: Winter will be here soon, and I’m wondering if more insulation could help lower my heating bills. Where should I add insulation?
A: If you venture outdoors in the winter with no hat or coat, you’ll feel much colder than you’d feel covered up. Similarly, when your home is not properly sealed and insulated, cold air sneaks in and heat escapes. Insulating your home to efficient levels can cut your heating and cooling costs by an average of 15 percent and make you more comfortable in your home.
Your attic is a great place to consider insulating. It’s usually accessible and easy to inspect for air leaks and insulation levels. And most homes do not have enough attic insulation. Insulation standards for new homes increased in 2012, and many homes built before then do not have the current recommended amount of attic insulation.
Insulation is graded by its “R-value”—the higher the R-value, the greater the insulating power. If you live in a mild climate, such as South Carolina, your attic should have a minimum grade of R-38, or about 13–14 inches of insulation. More may be needed depending on your home and exact climate.
How can you tell if your attic is lacking in insulation? Generally, if you can see the ceiling joists on your attic floor, there’s not enough insulation. A trained energy auditor can diagnose shortcomings with insulation or air leaks.
If you decide to add attic insulation, prepare the space first:
- If you store items, such as holiday decorations, in your attic, consider another storage location. If you must use your attic for storage, build a platform high enough to allow for the recommended level of insulation.
- If you live in an older home, check your attic’s electric wiring. Is the insulation around the wires degrading? Do you have outdated knob-and-tube wiring? If so, you may need to replace the wiring before proceeding.
Decide who will do your insulation work. Do-it-yourselfers should do some homework first. Installing insulation is messy, potentially dangerous and requires special equipment. If you’d rather use an insulation professional, discuss your attic’s specific needs before you hire a contractor:
- Be sure your contractor will seal any air leaks, such as around furnace flues and exposed air ducts in the attic. Air leaks can bring warm, moist air into the attic, which can reduce insulation value and create mold.
- Pay particular attention to your attic door or hatch. This entry point is a significant contributor to heat loss and heat gain in the home.
- It’s not usually necessary to remove existing insulation unless it’s wet, moldy or contains animal waste.
- Make sure there is sufficient ventilation in the attic. Warmth and moisture can build up in an improperly ventilated attic, leading to roof problems, such as roof rot or ice dams.
Two types of insulation work well for attic floors: batt/roll or blown-in/loose fill. Blown-in insulation requires special installation equipment, but it fills the space better than batt insulation, which can leave gaps unless it is carefully cut and placed around ceiling joists, vents and other impediments.
Most insulation is made from fiberglass, cellulose or mineral wool. Blown-in cellulose insulation offers superior coverage, high R-value and air-sealing abilities. It’s also treated with boric acid, which acts as a fire retardant and insect repellent.
Consult with an energy auditor or insulation contractor to determine what type and material of insulation will work best in your home.
Send questions to Energy Q&A, South Carolina Living, 808 Knox Abbott Drive, Cayce, SC 29033, email firstname.lastname@example.org or fax (803) 739-3041.