How to Calculate Batt Insulation Thickness Needs
With high energy costs, it's wise to make your house as efficient as you can. One way of doing this is by calculating the batt insulation thickness needs of your house, and adding the appropriate amount of insulation to save your heating and cooling costs. Does this Spark an idea?
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Instructions
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Find out the kind of insulation you have. With this information, you can determine the amount of R-value for each. For example, fiberglass batt insulation that's yellow or pink has an R-value of 3.1, whereas a Rockwool batt that's brown or dark gray has an R-value of 3.2.
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Determine the use of the batt insulation to calculate the thickness needs. For ceilings, have a value of R-49; for floors, the insulation must have R-25; for walls, R-19; and for basement walls, the insulation must have an R-value of 13.
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Measure the thickness of your insulation to calculate the batt insulation thickness needs. In your ceiling, you can use a ruler to measure the depth of the insulation. The same technique for measuring the thickness of insulation can be used in the basement. If you have a crawlspace, however, you will have to access the crawlspace before measuring the insulation. If you have a solid foundation, you can assume there is no insulation between the ground and the concrete. For the walls, you can count on an average thickness of 3 ½ inches of insulation.
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Multiply the R-value/inch for the type insulation you have times the inches of insulation you have measured when calculating the thickness needs of you batt insulation. For example, if your ceiling has 6 inches of batt insulation that's pink fiberglass, the R-value would be 3.1 per inch. If you times that by 6 (the thickness of the existing insulation) you'll get a total of 18.6 as an R-value.
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Subtract 18.6 for the R-value from the R-value that's recommended for the ceiling, which is R-49. The total will be 30.4.
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Divide 30.4 by the R-value/inch of the fiberglass insulation, which is 3.1. The total will be 9.8. This means that you will have to add at least 10 more inches of batt insulation when you are calculating the thickness needs of your insulation. Do the same calculations for the rest of your house.
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