CSLB C-20 HVAC ContractorVentilation and Air DistributionMedium
Per California's Title 24 Energy Code, what is the minimum insulation R-value generally required for new supply ducts installed in an unconditioned attic space in most California climate zones?
- AR-4.2
- BR-8
- CR-6
- DR-13
Show answer & explanationAnswer & explanation
Correct answer: B. R-8
Title 24 requires ducts located in unconditioned spaces such as attics to be insulated to a minimum of R-8 to limit thermal losses through the duct walls.
Why the other options are wrong
- A. Below the minimum required insulation level for attic ducts.
- C. Insufficient; does not meet current Title 24 minimum.
- D. Exceeds the typical minimum requirement, though sometimes used in high-performance homes.
Title 24 Duct Insulation
Ducts in unconditioned spaces like attics must be insulated to at least R-8 under California's Title 24 Energy Code to reduce conduction losses.
- Ducts in conditioned space have lower or no insulation requirement.
- Insulation reduces energy loss through duct walls, not air leakage.
- Duct sealing and insulation are separate but complementary requirements.
Memory trick: Attic ducts wear an R-8 coat.