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What's R Got To Do With It?

An R-value is the measure of a material's ability to resist conductive heat transfer. The higher the R-value, the more resistant that material is to transferring heat. R-values are stated on a variety of insulation products, from fiberglass batts to loose-fill cellulose. Full values are given for products of a uniform thickness, and per-inch values are given for materials that are blown or pumped into cavities.

The R-value of any building assembly, such as the floor, walls, or ceiling, equals the R-value of individual components added together. A typical stud-framed wall with 5.5 inches of fiberglass insulation (about R-3 per inch) has an overall R-value of approximately 20. Likewise, an earthen wall (such as adobe or rammed earth) insulated on the exterior with 4 inches of extruded polystyrene (R-4 to R-5 per inch), has a similar R-value. Even though the R-values of these two different wall structures is the same, the earthen wall will typically have less air leakage and much more thermal mass than the wood-framed one.

Stud-Framed 2 x 6 Wall R-Values

Component R-Value

Fiberglass batts, 51/2 in. (6 in. nominal)

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DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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