Tip of the day: Add insulation to lower your heating bills

Consumer Reports News: January 07, 2008 02:14 PM

The rising prices for home-heating fuels and electricity might not be the only culprit behind your higher utility bills this winter. An underinsulated roof could also be contributing to higher heating costs. Roughly 80 percent of older homes (those built before 1980) can benefit from additional attic insulation, according to the U.S. Department of Energy. Properly insulating and sealing your home can cut your heating—and cooling—bills by 10 percent, according to the DOE.

The major home centers obviously got hold of those statistics. Walk into any Home Depot or Lowe’s in a cold-weather region, and you’ll see stacks of fiberglass insulation in roll or batt form. You’ll also encounter bags of blown-in fiberglass or cellulose insulation, a loose-fill product made from shredded newspaper and other organic materials. The loose-fill stuff used to be a professional-installation-only product, but you can now rent the necessary equipment necessary to do the job yourself. (Blower rental is free at Lowe’s when you buy 25 or more bags of cellulose insulation.)

Before adding insulation, be sure you’ve sealed all air-leakage paths between the heated living space below and the cold attic above. Otherwise, your house will act like a giant chimney by sucking cold air in at the lower levels and allowing the warm air to escape into the attic space.

If you’re doing the work yourself, keep these points in mind:

• Blown-in insulation requires some technique to ensure the proper density of insulation. If it’s too fluffy, you won’t get the insulation benefit you are expecting, If it’s not fluffed enough, you will need a lot more material for coverage.
• For large open areas, rolls of fiberglass insulation are likely the easiest and quickest material to use, and its installation is not technique dependent.
• When adding to existing insulation, use a product without a vapor barrier as one likely exists. It will go beneath the insulation already in place in a cold-weather climate and on top of the insulation in a warm-weather climate.

Before you don the insulator’s cap, you’ve got some other things to consider. First and foremost, it probably won’t cost you much more to pay a contractor to insulate your attic. That’s because the discount rate a contractor gets on material (up to 50 percent off retail) cancels out a lot of the cost of labor. “The standard response when I give customers a price is, ‘I couldn’t do it myself for that,’” says Michael Delfino Jr., of Delfino Insulation Company, in Bohemia, New York.

Safety is a second consideration. Rental blowers are not as powerful as the equipment used by the pros, but they can do serious harm if you mishandle one. Not only that, a trained insulation contractor will spot hazards in the attic, whether from frayed wiring or open electrical boxes. And he’s less likely to put a foot through the drywall ceiling in your master bedroom.

We don’t mean to discourage you if you’re a determined DIYer. But if you’re going to insulate the attic yourself, do your homework first. R-value, or the measure of a material’s resistance to heat flow, is the critical factor when it comes to insulation. In most parts of the country, R-38 is required for roof insulation, though you should double-check recommendations for your region on the DOE’s Web site. Also remember that insulation is only one component part of a total heating system. Read more about home heating here.

If you decide to hire a contractor, get referrals from neighbors and verify that the pro you’re considering has the required licenses and insurance. To find a reputable installer in your area, visit the Insulation Contractors Association of America at www.insulate.org.—Daniel DiClerico

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