CSLB C-20 HVAC ContractorPlanning and LayoutMedium
Under California Title 24 energy standards, what is the minimum insulation R-value typically required for new supply and return ducts installed in an unconditioned attic space?
- AR-8
- BR-13
- CR-4.2
- DR-6
Show answer & explanationAnswer & explanation
Correct answer: A. R-8
Title 24 requires ducts located in unconditioned spaces such as attics to be insulated to a minimum of R-8 to reduce conductive heat gain/loss through the duct wall before conditioned air reaches the occupied space.
Why the other options are wrong
- B. R-13 is a wall cavity insulation value, not a duct insulation standard.
- C. R-4.2 is below the current Title 24 minimum for attic ducts.
- D. R-6 is sometimes used for ducts in other unconditioned spaces but not the attic minimum.
Title 24 Duct Insulation
California's Title 24 energy code requires ducts in unconditioned spaces like attics to carry a minimum insulation level to limit thermal losses.
- Attic ducts: minimum R-8 insulation
- Reduces conductive gains/losses through duct walls
- Works alongside CFM25 leakage testing requirements
Memory trick: Attic ducts wear an R-8 coat to stay comfortable.