math
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R-value question (insulation)
Hello,
I'd like to know if the R-value of different layers adds up as the following:
I've got a sheet of material which has a R-value of 3. I put a soda can on top.
If I stack two sheets of this material, will the R-value on top of them (hence the one that the soda can will be insulated by) be 6?
Thank you
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Ephesian
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is R-value the length/width of material?
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smaerd
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I'd have to pull out my physics notes. Though I checked wiki for a quick reminder and it answers you're question.
| Quote: | | Increasing the thickness of an insulating layer increases the thermal resistance. For example, doubling the thickness of fiberglass batting will
double its R-value, perhaps from 2.0 m²K/W for 110 mm of thickness, up to 4.0 m²K/W for 220 mm of thickness. Heat transfer through an insulating
layer is analogous to adding resistance to a series circuit with a fixed voltage. However, this only holds approximately because the effective thermal
conductivity of some insulating materials depends on thickness. The addition of materials to enclose the insulation such as sheetrock and siding
provides additional but typically much smaller R-value. |
The classic answer, "depends on the material".
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Magpie
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The simple answer is "yes." This presumes that you do not alter the R value of the insulation during installation. Eg, if you compress a
fiber-glass batt you will decrease its R value.
The single most important condition for a successful synthesis is good mixing - Nicodem
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