European windows in California
California runs its own energy code - Title 24, Part 6 - instead of the IECC, with 16 climate zones from the foggy north coast to the Sierra. For windows it comes down to two numbers almost everywhere: U-factor 0.30 and SHGC 0.23, from Los Angeles and San Diego to San Jose, Sacramento and Palm Springs.
California climate zones and code targets
Title 24 and 16 state climate zones instead of IECC.
| Title 24 climate zone | Representative cities | U-factor max | SHGC max |
|---|---|---|---|
| 1 and 3 (north coast, Bay Area coast) | Eureka, San Francisco, Oakland, Monterey | 0.30 | not required |
| 5 (central coast) | San Luis Obispo, Santa Maria | 0.30 | not required |
| 4 (inland Bay Area) | San Jose, Los Gatos, Palo Alto | 0.30 | 0.23 |
| 6-9 (Southern California coast and basin) | Santa Monica, Malibu, Los Angeles, Pasadena, Irvine, San Diego | 0.30 | 0.23 |
| 10-15 (inland valleys and desert) | Riverside, Sacramento, Fresno, Palm Springs | 0.30 | 0.23 |
| 16 (mountains) | Lake Tahoe, Truckee, Mammoth Lakes | 0.30 | 0.23 |
Title 24, Part 6 residential prescriptive package for new construction - the same 0.30 / 0.23 targets my Los Angeles briefs carry. Projects can trade these numbers off on the performance path.Always verify against the local jurisdiction's adopted amendment before locking a spec - see the full climate zone cheat-sheet for how this plays out nationally.
California does not use the IECC for homes. The California Energy Commission writes its own energy code - Title 24, Part 6 - updated on a three-year cycle, with 16 building climate zones that do not line up with the IECC map. The prescriptive package asks for a 0.30 U-factor everywhere and caps SHGC at 0.23 in every zone except the mild coastal ones (1, 3 and 5), where there is no SHGC limit.
The prescriptive package also limits total window area to about 20% of the conditioned floor area, with a tighter cap on west-facing glass. Most of the houses I quote in California - hillside builds with glass walls and lift-and-slide doors - go over that, so the energy consultant runs them on the performance path instead: the CBECC-Res model and a CF1R compliance report, where better glass on one elevation can pay for more glass on another. Send me the CF1R targets early and I build the glass package to them.
Title 24 wants the U-factor and SHGC to be NFRC-rated. A window without an NFRC rating has to use the Energy Commission's default values, which are conservative enough that a high-performing European unit can still fail on paper. That is the single biggest difference between quoting California and quoting Texas or Colorado - see the section below.
The NFRC rating is the California hurdle - not the glass
Most European window systems clear 0.30 easily on their own numbers: double-glazed units typically run about U-0.22 to 0.32 and triple-glazed about U-0.13 to 0.19 once converted to US units. The problem in California is not performance, it is proof. The Title 24 compliance documents expect NFRC-certified values, and a European CE declaration, however good, is not an NFRC label.
So for California I narrow the system list before pricing. On the Los Gatos project in the Santa Clara hills, the schedule is priced two ways: inswing tilt and turn in Max Light Modern, and outswing casements in SlimLine 38 with NFRC-rated glazing for the submittal. The architect and the energy consultant choose with both prices and both compliance routes on the table. On the Los Angeles hillside house, the brief said outright: NFRC-rated glazing, U 0.30 and SHGC 0.23 maximum - so the quote is built around triple glazing with solar-control coatings in aluminum-clad wood.
In my estimator, the NFRC option adds a 5% planning allowance, and the exact rated configuration is confirmed before ordering. If your plan reviewer or energy consultant will only accept a label, tell me before a system is chosen - it changes which systems are on the list, not just the price.
Wildfire zones: tempered glass on every pane
Large parts of the places I get California inquiries from - the Santa Cruz Mountains above Los Gatos and Saratoga, the Santa Monica Mountains, the hills above Pasadena and Malibu - sit in mapped Fire Hazard Severity Zones or the wildland-urban interface. New homes there fall under Chapter 7A of the California Building Code, and for exterior windows the usual compliance route is multi-pane glazing with at least one tempered pane. The other routes are glass block, a fire-resistance-rated assembly, or a window tested to the State Fire Marshal's standard.
Tempered glass is a standard option on every system I source, so I specify it on every pane of a Chapter 7A schedule rather than only where the code reaches - it also takes care of the safety-glazing locations near doors, stairs and wet areas in one decision. What I cannot supply is a fire-rated window assembly, so if your fire official asks for one, flag it before the schedule is locked. Check the state's hazard-zone map for the lot early; the zone also decides the vent, deck and siding details around the windows.
Big glass, sun and salt air
California designs push glass harder than any other state I quote. The Los Angeles projects on my books include a four-panel lift-and-slide opening 22 feet wide, and that is not unusual here. Two things follow. First, SHGC 0.23 on a west-facing glass wall in Zone 9 is a real constraint - a solar-control low-E coating gets you there on clear-looking glass, but I check visible light transmittance on the same sheet so the view does not go grey. Second, panel weight: triple-glazed lift-and-slide sashes get heavy fast, which is why the hardware, not the glass, usually sets the maximum panel size.
On the coast, salt air is the long-term issue rather than heat. For aluminum and aluminum-clad wood within sight of the ocean I ask for a seaside-grade pretreatment under the powder coat and stainless fixings, and I write the cleaning schedule into the handover - rinsing the frames a few times a year does more for a Malibu or La Jolla window than any coating upgrade. Inland and in the Central Valley, the cooling load leads, and double glazing with a strong low-E coat is usually the right price-to-performance call; triple glazing earns its place in the Sierra (Zone 16) and on acoustic sites near freeways and flight paths.
Projects in California
Vallecitos Way
Los Gatos, CA - Residential - Custom Home + ADU
New main house with an attached ADU in the Santa Clara hills. 39 frames covering 1,090 sq ft - casements, fixed units and nine door assemblies, all with simulated divided lights and fly screens. Two routes on the table: inswing tilt & turn in Max Light Modern, or outswing casements in SlimLine 38 with NFRC-rated glazing for the California submittal.
Max Light Modern, SlimLine 38 - Double-glazed tempered low-e
Quail Drive
Los Angeles, CA - Residential - Hillside New Build
Compact hillside house with a concrete masonry base, dark facade panels and a sloped metal roof. 13 units and about 410 sq ft of glass, mostly fixed, with three glass swing doors. The brief is tight - an NFRC-rated glazing package, U 0.30 and SHGC 0.23 maximum for California Title 24 - so the quote is built around triple glazing with solar-control coatings in aluminum-clad wood.
Clad Hidden Sash - Triple-glazed tempered low-e
Westerly Terrace
Los Angeles, CA - Residential - Custom Home
Second Los Angeles project from the architect of Quail Drive, specified in the same aluminum-clad wood system. 13 windows - awnings, large fixed units and a horizontal slider - plus five lift & slide doors, about 880 sq ft in total, with the largest door a four-panel opening 22 feet wide. Currently in pricing.
Clad Hidden Sash, Timber Lift & Slide - Triple-glazed tempered low-e
Shipping to California
Every project ships DDP - duties, ocean freight, marine insurance, and customs clearance already in the price. California projects typically route through the Port of Los Angeles / Long Beach for Southern California, Port of Oakland for the Bay Area. Plan on about 14 weeks from approved estimate to delivery as a starting point. West Coast sailings from Europe run through the Panama Canal, so I confirm the routing and the arrival date per order, DDP with freight, customs clearance and duty included.
Cities I ship to across California: Los Angeles, Malibu, Santa Monica, Pasadena, San Diego, Santa Barbara, San Francisco, Oakland, Palo Alto, San Jose, Los Gatos, Sacramento, Lake Tahoe, and anywhere in between.
Run your window schedule through the project estimator for a landed budget number in about two minutes, or send it directly and I will have a first pass back the same or next working day.
California - common questions
Do European windows meet California Title 24?+
Yes, on performance - most European systems beat the 0.30 U-factor in the Title 24 prescriptive package, and a solar-control low-E coating reaches the 0.23 SHGC cap. The catch is documentation: Title 24 expects NFRC-rated values, and unrated windows fall back to conservative default numbers. I quote NFRC-rated units on selected systems for California submittals and confirm the rated configuration before ordering.
Do I need NFRC-rated windows in California?+
For a normal permit, effectively yes - Title 24 compliance uses NFRC-certified U-factor and SHGC values, and without them the energy model has to use the state's default values, which most good windows fail on paper. Ask your energy consultant what the CF1R needs before the system is chosen; it narrows the list of systems I price.
What windows do I need in a California wildfire zone?+
Under Chapter 7A of the California Building Code, exterior windows in a Fire Hazard Severity Zone or wildland-urban interface area usually need multi-pane glazing with at least one tempered pane, glass block, a fire-resistance rating, or a window tested to the State Fire Marshal's standard. I specify tempered glass on every pane for those lots. A fire-rated window assembly is outside what I supply.
Building in California?
Send me your window schedule and I'll have a budget estimate back to you the same or next working day. No obligation.