Energy efficient windows in Los Angeles are judged by two ratings on the window label: the U-factor and the solar heat gain coefficient (SHGC). ENERGY STAR asks for a U-factor of 0.28 or lower and an SHGC of 0.23 or lower in Los Angeles County, and the LADWP rebate is $2 per square foot for windows with a U-factor of 0.30 or lower and an SHGC of 0.25 or lower. DuloCore checked these pages on November 5, 2026.
Rebates outside Los Angeles are in our guide to window rebate programs in California.
What Makes a Window Energy Efficient in Los Angeles?
As of November 5, 2026, a window meets the ENERGY STAR criteria for Los Angeles County when its U-factor is 0.28 or lower and its SHGC is 0.23 or lower, the South-Central zone limits.
The U-factor measures how well a window insulates, and the SHGC is the share of the sun's heat that the glass lets in. A lower number is better for both. The ENERGY STAR page for Los Angeles County places the county in its South-Central zone and requires certified ratings for both numbers.
The National Fenestration Rating Council (NFRC) label on each window lists its energy performance ratings. Our ENERGY STAR windows label guide explains how to read it.
What Does the California Energy Code Require for Replacement Windows?
Replacement windows in Los Angeles homes must meet the 2025 California Energy Code, whose limits depend on the climate zone: in Climate Zones 6 through 10, the U-factor cap is 0.30 and the SHGC cap is 0.23.
The 2025 code applies to buildings whose permit applications are filed on or after January 1, 2026, according to the California Energy Commission.
| Energy Code rule (2025 standards) |
U-factor |
SHGC |
| Climate Zones 6 through 10 |
0.30 or lower |
0.23 or lower |
| Most other climate zones |
0.27 or lower |
varies by zone |
| Small replacement, 75 square feet or less |
0.40 or lower |
0.35 or lower |
For single-family homes on the prescriptive path, new windows that replace old ones of the same total area must meet these limits under Section 150.2 of the 2025 Building Energy Efficiency Standards. The small-replacement row is an exception in that section.
Which Climate Zone Is My Los Angeles Home In?
The California Energy Commission splits the state into sixteen climate zones, and the window limits for a Los Angeles home depend on the zone of its address.
The Energy Commission climate zone page links a search tool that places any California address in its zone. Check the zone before you order, since a ZIP code can hold more than one.
Which Windows Qualify for the LADWP Rebate?
As of November 5, 2026, LADWP lists a $2 per square foot rebate for replacement windows with a U-factor of 0.30 or lower and an SHGC of 0.25 or lower, while funding lasts.
The LADWP Consumer Rebate Program page asks for each window's ratings on the NFRC label or the manufacturer's order confirmation. LADWP's terms add three rules: the windows must meet ENERGY STAR Version 6.0, they must replace inefficient windows, and you need a final approved permit from the Los Angeles Department of Building and Safety. New construction, additions and ADUs are excluded.
Amounts and documents are covered in our Los Angeles window replacement rebates page.
The full claim process is in our LADWP Consumer Rebate Program application guide.
Can Income-Qualified Los Angeles Homeowners Get Windows Replaced for Free?
Possibly: the weatherization program run by California's Department of Community Services and Development (CSD) serves low-income homeowners and renters, and its measures can include repairing or replacing windows.
The CSD weatherization page lists window repair or replacement among the improvements, and eligibility depends on income, household size, energy use and other factors.
LADWP customers can also apply to the Home Energy Improvement Program, which gives free efficiency upgrades identified in a home assessment by LADWP technicians. It is open to single-family homes, condos, townhomes and buildings of 4 units or less. The program page does not say whether windows are among those upgrades.
Did the Federal Tax Credit for Energy Efficient Windows End?
Yes, the federal 25C credit for energy efficient windows ended for property placed in service after 2025, so it does not cover windows installed in Los Angeles homes in 2026.
Frequently Asked Questions
Does a window that meets the LADWP rebate also meet the Energy Code?
In Climate Zones 6 through 10, only if its SHGC is 0.23 or lower. LADWP accepts up to 0.25, while the 2025 Energy Code caps SHGC at 0.23 in those zones, so buy to the lower number.
Does replacing only the glass count as a window replacement?
No, the Energy Code treats new glass in an existing sash and frame, or a new sash in an existing frame, as a repair, provided the replacement performs at least as well as the original.
How long do I have to apply for the LADWP window rebate?
LADWP requires the application to be postmarked within 12 months of the purchase date, and its funding is first-come, first-served.
Planning new windows in Los Angeles? See which rebates fit your home with the free eligibility check.
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