Window Climate Specs for San Fernando, CA
San Fernando sits in IECC climate zone 3B, which sets the energy-performance bar for any window installed here. Below that, a short list of San Fernando's longest-licensed window contractors can turn a spec into an actual installed window.
Licenses checked · California Contractors State License Board
3BIECC climate zone · ENERGY STAR South-Central zone
San Fernando's climate zone, in plain terms
That load is the actual argument for paying up for a better U-factor in San Fernando, separate from anything a brochure claims.
Zone 3B's requirement is the floor; San Fernando'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 3.5 mi away.
What FEMA's risk data says about San Fernando
FEMA scores Los Angeles County's winter-weather risk as Relatively Moderate and its flood risk as Very High.
Winter risk in San Fernando 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 Fernando contractor, not one.
- Strong wind
- Relatively Moderate
- Winter weather
- Relatively Moderate
Data: FEMA, National Risk Index for Natural Hazards - County-level table, v1.20 (v1.20, December 2025).
Guides to finish before San Fernando 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.
San Fernando's longest-licensed window installers
Oldest license first, newest last, pulled directly from the state's file. This list isn't for sale.
- PT Windows INCVerify license
- Mighty Builders INCVerify license
- Alamo Glass INCVerify license
- High Quality GlassVerify license
- West Coast Shower GlassVerify license