Core TradesQuestion 148 of 700
Under the California Energy Code, supply ducts run through an unconditioned attic must generally be insulated to a MINIMUM of:
a.R-4.2
b.R-6
c.R-13
d.R-8
Explanation
Ducts located in unconditioned space such as an attic must have at least R-8 insulation to limit conductive heat loss and gain where temperatures are extreme. R-6 applies to ducts in more moderate locations, R-4.2 is below current requirements, and R-13 exceeds the minimum for ducts.
Law Reference: 2025 CA Energy Code §150.0(m)Practice all 700 questions free — no signup required.
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