Reduce the Cost of Heating With Home Insulation

Your family can stay warmer while you reduce the cost of heating with home insulation, including manufacturer's recommendations by weather zone, R-value per inch, insulation density and moisture permeability.


| November/December 1982



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Chart: Types of home insulation.


MOTHER EARTH NEWS STAFF

Learn how to keep your house warmer and how to reduce the cost of heating with home insulation. 

In the search for ways to reduce the cost of home heating, it's gradually being recognized that it's a heck of a lot easier and less expensive to hang onto the warmth you've got than it is to produce more . . . whether that heat is garnered from another unit of our ever-depleting supplies of fossil fuels or from benign solar energy. And the recent success of superinsulated housing is, perhaps, the strongest testimonial to the fact that thermal conservation measures are becoming accepted practices in the construction of even conventional-looking homes when you choose to reduce the cost of heating with home insulation.

And, of course, the growth of interest in insulation has led to a strong marketplace, with dozens of different products being offered . . . both for new construction and for retrofit. In this article—and in the accompanying side pieces—we'd like to try to unravel some of the mystery surrounding different types of insulation. As you'll learn, each material has its place, and proper selection will help you to put up the most effective thermal barriers—with the greatest ease—for the least amount of money.

CLASS AND TYPE

Insulants generally fall into one of three categories: batts and blankets, which fit into a home's wood framing . . . loose fill, which is blown or poured between joists in a ceiling or into closed wall spaces . . . and rigid board, which can serve as a sheathing material. (Bans are distinct from blankets in that they have no facing, while the latter have either a paper material for stapling to studs or a foil layer that both secures the layers and reflects radiant heat.)

R-VALUE PER INCH

The importance of the thermal resistivity (R-value) of a particular insulant is most evident in situations where there's a limited amount of space to fill with the material. Within a stud wall space, for example, 3-1/2 inch fiberglass will produce a finished R-value of about 13. By filling the space with polyurethane foam, however, that same 3-1/2 inch space could produce a rating of about R-26. (The cost of all that polyurethane would be quite high, though.) In locations where space isn't at a premium, however—in attics, for instance—it will generally be more practical to simply stack up less costly materials to a greater depth.

DENSITY OF HOME INSULATION

Of course, the amount of insulation that can be placed in a given location will sometimes be limited by the weight the material will add to the building. Loose-fill insulants—such as vermiculite and perlite—can be quite heavy. And, in an attic space where the insulation is resting atop the ceiling, loads over three pounds per square foot may cause the ceiling to sag. So when you're studying the figures we've supplied in the accompanying chart, bear in mind that the weights per square foot listed all apply to a 12 inch material thickness.





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