Which glass Title 24 requires in LA climate zones and fire zones

Written and checked by the DuloCore research team. Last verified: November 11, 2026.

The City of Los Angeles stretches across three California building climate zones, and its hillsides add wildfire rules, so the right window rating depends on your ZIP code and parcel; the money side is on the home page estimator.

Find your climate zone: 6, 8 or 9

California's Energy Code uses sixteen climate zones, and window standards depend on which one a building is in (California Energy Commission). The CEC's ZIP code list puts these City neighborhoods in:

For an exact address, use the CEC's EZ climate zone search linked from the CEC climate zone page.

What the 2025 Energy Code asks of replacement windows

Under Section 150.2(b)1B of the 2025 Energy Code, replacement windows of the same total area must meet the U-factor and SHGC values of Table 150.1-A. That table lists a maximum U-factor of 0.30 and a maximum SHGC of 0.23 in zones 6, 8 and 9. Exception 1 lets a replacement of no more than 75 square feet of vertical glass use a U-factor up to 0.40 and SHGC up to 0.35 in those zones. New glass in an existing sash and frame counts as a repair.

How that lines up with the LADWP rebate

The LADWP rebate asks for U-factor 0.30 or lower and SHGC 0.25 or lower. On a job over 75 square feet, the code's 0.23 SHGC is the tighter number, so a window rated 0.24 or 0.25 could meet LADWP's rule yet miss the code's prescriptive value. Ask for both numbers on the NFRC label, U 0.30 or lower and SHGC 0.23 or lower, and confirm with your installer how they will document compliance for LADBS.

Valley heat versus the coast

LADWP describes SHGC as the fraction of solar radiation a window lets in (LADWP), so a lower number keeps out more sun heat. The Valley shares zone 9 with downtown, while the beach side is zone 6, and the CEC assigns separate zones because the climates differ. In a Valley house with large west- or south-facing glass, a low SHGC does the most work against afternoon sun. On the coast the same code limits apply, and daylight and view may matter more to you than pushing SHGC lower still.

Wildfire zones: multi-pane, tempered glass

CAL FIRE's Office of the State Fire Marshal classifies land as Moderate, High or Very High Fire Hazard Severity Zones; the maps rate hazard, not risk (OSFM). An LADBS plan check sheet for Very High zones, "based on City maps", requires exterior windows to be insulating-glass units with at least one tempered pane, glass block, rated for at least 20 minutes under NFPA 257, or tested to SFM 12-7A-2 (former building code Section 708A.2.1).

That sheet dates from the 2017 code cycle. For 2026, the same glazing rule sits in Section 504.8 of the California Wildland-Urban Interface Code, Title 24 Part 7, as LA County Building and Safety notes for unincorporated areas. Confirm the current City wording with LADBS, and check your parcel's zone in ZIMAS or the OSFM viewer. Our permit page covers the rest of the paperwork.