If you’re serious about conserving resources, one of the best things you can do is adding insulation to your home. It reduces the power bill on days when the air conditioning is running, as well as the heat bill, regardless whether the house is heated by natural gas or electricity or both.
The easiest way to install insulation is to buy it as fiberglass batts. It can be added where there’s already a layer of blown-in material, recognizable as loose, fluffy stuff, or where there are already batts in place, looking more like a smooth, continuous layer.
Cutting it to size is easiest with long-bladed paper scissors. It’s not advisable to add fiberglass that has a paper backing to an existing layer, because the backing is intended as a moisture barrier and can lock up water vapor within the insulation. Sometimes it’s cheaper than the unfaced kind, though. In that case you can remove the paper backing by loosening an edge, and then “combing” the paper off with gentle strokes using a stirring stick from the paint department.
To figure out what to buy, check the thickness of the existing insulation. The absolute minimum for a North Georgia attic, R-30, is about 9 inches thick when lying flat. Sometimes the rolls of R-13 are the best price per square foot, so I like to remove the paper backing and place two layers of R-13 on top of the old R-30. This makes for a comfortable insulation value of R-56. The improvement will be noticeable immediately, during any season.
If the R-30 price is similar to that of two R-13 layers, this simplifies matters. Simply place unfaced batts on top of what’s already there. Where existing insulation reaches the top of the rafters, you can install the new batts at a 90-degree angle. This minimizes the potential for air leaks.
Floor insulation is also important because in the summer, chilled house air wants to sink down and escape through the floor. Home centers have inexpensive wire support rods available. Simply push them between the joists at about 16-inch intervals to hold the material snugly against the floor.
Where there’s no insulation yet at all, install it with the backing in place and facing toward the “house” side of the floor or ceiling. Never compress the material because it’s the air between its strands that have insulating qualities, not the fiberglass itself.
Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at gainesvilletimes.com.