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Material
room T metals feel cold
Copper
391
great for pulling away heat
Gold
295
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Stainless Steel
10–25
why cookware uses S.S.
Glass, Concrete,Wood
0.5–3
buildings
Many Plastics
~0.4
room T plastics feel warm
G-10 fiberglass
0.29
strongest insulator choice
Stagnant Air
0.024
but usually moving…
0.01–0.03
can be better than air!
Styrofoam
3
comments
422
Aluminum
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Silver
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•  Note that these examples use the non-SI definition and are per
inch. Vacuum insulated panel has the highest R-value of
(approximately 45 in English units) for flat, Aerogel has the next
highest R-value 10, followed by isocyanurate and phenolic foam
insulations with, 8.3 and 7, respectively. They are followed
closely by polyurethane and polystyrene insulation at roughly R–
6 and R–5. Loose cellulose, fiberglass both blown and in batts,
and rock wool both blown and in batts all possess an R-value of
roughly 3. Straw bales perform at about R–1.45. Snow is
roughly R–1.
•  Absolutely still air has an R-value of about 5 but this has little
practical use: Spaces of one centimeter or greater will allow air
to circulate, convecting heat and greatly reducing the insulating
value to roughly R–1
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