Insulation R Values

The Old House Web

Confused about R-values, rolled or blown-ininsulation, vapor barriers and other insulation terms? This series of stories,adapted from the U.S. Department of Energy "InsulationFact Sheet" explains the ins and outs of home insulation -- and may helpyou save significantly on your heating and cooling costs.

Talk to your contractor about R-values

You should obtain cost estimates from several contractors for a statedR-value. Make sure you describe the job in writing in the same terms to eachone. You may want to ask each contractor about their air-sealing services aswell. Remember that you want good quality materials and labor, as well as price.

Do not be surprised to find the quoted prices for a given R-valueinstallation to vary by more than a factor of two. When you talk to acontractor, talk of R-values. Don't forget that R-values are determined bymaterial type, thickness, and installed weight per square foot, not by thicknessalone.

Each bag of insulating material used by the contractor should be marked withan R-value for the area to be covered. Although these figures may differ amongmanufacturers, the area figure will tell you the right number of bags to be usedfor loose-fill. Similarly, packages of other types of insulation should beidentified by their R-value.

It is important that you check that the properamount is installed in your residence. Ask the contractor to attach verticalrulers to the joists prior to a loose-fill installation in your attic to helpyou see that the proper depth was installed. Also, the installer must provide asigned and dated statement describing the insulation installed, statingthickness, coverage area, R-value, and number of bags installed. In some areas,infrared thermography services are offered to help discover any gaps in theinsulation.

Consumers may want to have their attic R-value evaluated to ensure that theyare getting what they paid for. You can evaluate batt insulation installation bymeasuring the batt thickness and by checking for gaps between batts."Cookie-cutting" is the insulation industry recognized procedure ofevaluating installed loose-fill insulation. Many independent (third-party) firmsoffer "cookie-cutting" services to homeowners throughout the country.Contact the InsulationContractors Association of America for a list of firms that offer theseservices; they can also provide you with brochures and fact sheets aboutinspecting your insulation job.

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