California Title 24 Recessed Lighting Airtight Compliance

Why this matters

California Title 24, Part 6, Section 150.0(k) (2022 Energy Code) requires that all recessed luminaires installed in insulated ceilings be IC-rated, airtight (AT), and gasketed. The regulation exists to stop conditioned air from leaking through the ceiling into the attic, which on a typical 2,000 sq ft home with 12 cans equals roughly 100 to 200 CFM of bypass loss. Inspectors fail every fixture that lacks the ASTM E283 airtight label, and the contractor pays for re-trim or full luminaire replacement out of pocket because customers will not absorb the rework. Knowing the exact ASTM test, the label requirements, and the AHJ-acceptable trim choices keeps the job under one truck roll.

Mandatory luminaire criteria under 150.0(k)

The 2022 Energy Code requires every recessed luminaire installed in a ceiling enclosing conditioned space below an unconditioned attic to meet ALL of the following:

• IC (Insulation Contact) rated per UL 1598
• Air-tight, with leakage rate not exceeding 2.0 CFM at 75 Pa per ASTM E283
• Gasketed at the trim-to-ceiling junction
• Sealed at all penetrations through the housing
• Listed as a complete luminaire including the LED engine; LED retrofits installed into older non-AT housings do not comply unless the housing itself is also AT-rated

Conditioned-to-conditioned ceiling penetrations (multistory residential) do not require AT rating but still require IC rating where insulation is present.

Lamp source requirements

Per Section 150.0(k) and the JA8 reference appendix:

• All permanent lighting must be classified High Efficacy
• For residential occupancies, JA8 listed luminaires or lamps meeting the JA8 efficacy and quality criteria are required in living spaces, kitchens, bathrooms, garages, laundry, and utility rooms
• JA8 requires minimum 45 lumens per watt for omnidirectional, dimmable to at least 10 percent, CRI 90 or higher, color temperature labeled
• Non-JA8 light sources are restricted to specific exempt applications (closets under 70 sq ft, certain outdoor applications)

Selecting an AT-rated housing

Confirm during plan review:

• The luminaire spec sheet states "ASTM E283 tested, less than 2 CFM at 75 Pa"
• The CEC modernized appliance database (MAEDBS) lists the product with JA8 designation
• The housing carries a permanent label visible during inspection
• The trim ring includes a foam or rubber gasket

Common qualifying housings as of 2024: Halo H7ICAT, Juno IC1, Lithonia AFICT, Cooper Halo H99ICAT, Eaton All-Pro RA4ICAT. Always cross-check the current CEC list before bulk ordering.

Installation procedure

1. Cut the ceiling opening to the housing template (typically 5 inches for a 4 inch nominal can, 6 to 6.5 inches for a 5 inch nominal). Do not oversize; the gasket relies on a snug fit.
2. Connect line voltage through the housing's integral junction box per NEC 410.118 (junction box accessible above the ceiling line).
3. Install the housing flush with the ceiling drywall. The collar must contact drywall continuously around the perimeter; gaps will leak.
4. From above (attic side), if penetrations are present for conduit, MC cable, or NM cable connectors, seal each with a UL Listed firestop putty or fire-rated caulk compatible with the housing material. Common product: 3M FB-3000 WT or Hilti FS-ONE MAX.
5. Install attic blanket insulation directly contacting the housing (IC rating permits this; do not leave a clearance gap that would defeat the air seal).
6. Install the trim. The gasket compresses between the trim and the ceiling drywall. Verify the gasket is intact; replace any trim with damaged gasket before energizing.
7. Confirm the lamp installed is JA8 compliant. Many AT-rated housings ship with non-JA8 trim accessories; the inspector checks the lamp installed at the time of inspection, not the spec sheet.

High-density insulation considerations

Loose-fill cellulose, blown fiberglass, and dense-pack cellulose all may be installed in direct contact with an IC-AT housing. However:

• Spray polyurethane foam (SPF) applied directly to a housing voids the UL listing of most housings; verify the housing's listing permits SPF contact. Many manufacturers void warranty under SPF.
• The contractor is responsible if SPF is sprayed on the housings without manufacturer approval; document with photos before insulation is installed.

Common inspection failures

• Trim gasket missing, damaged, or compressed past its sealing limit
• Housing oversized hole patched with caulk (caulk-and-pray; the inspector rejects)
• Aftermarket LED retrofit module installed in an old non-AT can with no AT label on the assembled unit
• Lamp installed is not JA8 listed (typical: builder-grade BR30 not on the CEC list)
• Conduit knockouts in the housing left open above the ceiling

Documentation

The contractor's CF1R-LTI installation certificate must list:

• The Title 24 climate zone of the project
• Each luminaire by location and product number
• Confirmation that all installed luminaires are JA8 listed and IC-AT
• The responsible person's contractor license number

The CF1R-LTI is required for residential alterations adding more than 10 luminaires, all new construction, and all kitchen lighting alterations affecting more than 50 percent of the luminaires.

References

• California Code of Regulations, Title 24, Part 6, Section 150.0(k) (2022 Energy Code)
• California Energy Commission Joint Appendix JA8 High Efficacy Light Sources
• UL Standard 1598 Luminaires, Standard for Safety
• ASTM E283-19 Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors
• NEC 2023 Article 410 Luminaires, Lampholders, and Lamps