Window Climate Specs for San Diego, CA

San Diego sits in IECC climate zone 3B, which sets the energy-performance bar for any window installed here. Below that, a short list of San Diego's longest-licensed window contractors can turn a spec into an actual installed window.

Licenses checked September 30, 2026 · California Contractors State License Board

3BIECC climate zone · ENERGY STAR South-Central zone

What zone 3B means for a San Diego window

San Diego-Chula Vista-Carlsbad, CA runs a January average near 57°F and climbs to about 72°F by July, a swing that adds up to roughly 1,320 heating degree days most winters, with 1,019 on the summer cooling side of the ledger.

That load is the actual argument for paying up for a better U-factor in San Diego, separate from anything a brochure claims.

Zone 3B's requirement is the floor; San Diego's specific load is what tells you whether beating that floor is worth the extra cost.

Data: U.S. EPA / DOE, ENERGY STAR, ENERGY STAR Version 7.0 Climate Zones by County/ZIP (Windows, Doors, and Skylights) (V7.0); Pacific Northwest National Laboratory (DOE Building America), Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates (PNNL-33270) (2021 IECC), from the nearest NOAA station 1.5 mi away.

Storm and weather risk around San Diego

FEMA scores San Diego County's winter-weather risk as Relatively Low and its flood risk as Very High.

Winter risk in San Diego weighs on U-factor and condensation resistance; flood risk weighs more on sill height and drainage detailing than on the glass package.

Treat these as two separate conversations with a San Diego contractor, not one.

Hurricane: Very Low
Strong wind: Relatively Moderate
Winter weather: Relatively Low

Data: FEMA, National Risk Index for Natural Hazards - County-level table, v1.20 (v1.20, December 2025).

Guides to finish before San Diego window bids come in

How to Read an NFRC Window Label Four numbers on one sticker decide most of a window's real-world performance. Here's what each one means.
ENERGY STAR Window Criteria by Climate Zone ENERGY STAR splits the country into four zones, each with its own numbers. Here they are, and why the Northern zone works backward from the other three.
Impact Windows vs. Shutters in Florida's Hurricane Zones Florida gives homeowners two paths to a protected opening. Here's how each one is tested, and where the HVHZ raises the bar further.

Window installers with the longest license records in San Diego

Oldest license first, newest last, pulled directly from the state's file. This list isn't for sale.

R B Glass & Mirror INCWindow and glass contractor · licensed 42 years · 92127Verify license
Bob's Glass & Screen COWindow and glass contractor · licensed 38 years · 92126Verify license
Cassell GlassWindow and glass contractor · licensed 34 years · 92129Verify license
Sorrento Glass & Mirror CompanyWindow and glass contractor · licensed 34 years · 92111Verify license
Advance Glass And MirrorWindow and glass contractor · licensed 33 years · 92110Verify license
Heritage GlazingWindow and glass contractor · licensed 32 years · 92111Verify license
Clear Concepts Windows & DoorsWindow and glass contractor · licensed 29 years · 92120Verify license
Design Synthesis INCWindow and glass contractor · licensed 27 years · 92126Verify license
Mira Mesa Glass & Screen INCWindow and glass contractor · licensed 27 years · 92126Verify license
Park Place Screen & Glass INCWindow and glass contractor · licensed 27 years · 92116Verify license
Jim Olson Construction INCWindow and glass contractor · licensed 26 years · 92106Verify license
Discount Glass & MirrorWindow and glass contractor · licensed 26 years · 92121Verify license

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