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November 23, 2014

November 23, 2014

Posted by **James** on Thursday, July 19, 2012 at 4:15pm.

The R value is 24 ft^2 Fh/BTU. How do I get this answer?

- Physics -
**drwls**, Thursday, July 19, 2012 at 6:54pmR is the reciprocal of the amount of BTU of heat transfered across 1 ft^2 in 1 hour with a temperature difference of 1 F.

1/R = 8.6*10^-6*3600 s*(1.0 degF)/(8.9/12 ft)

R = 24 ft^2*degF*h/BTU

- Physics -
**James**, Thursday, July 19, 2012 at 10:53pmThank you!

Could you write out just the basic equation that you used?

- Physics -
**James**, Thursday, July 19, 2012 at 10:57pmThe equation I found in my text book doesn't mention time being a factor when calculating R.

I have R= L/k

where L is length and k is thermal conductivity.

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