Core TradesQuestion 210 of 700
A wall assembly has a total thermal resistance of R-20. What is its approximate overall U-factor (heat-transfer coefficient)?
a.0.05
b.0.20
c.2.0
d.20
Explanation
U-factor is the reciprocal of total R-value: 1 / 20 = 0.05. The 0.20 and 2.0 answers misplace the decimal, and 20 simply repeats the R-value; a lower U-factor indicates better insulating performance.
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