What San Jose Homes Need From a Replacement Window
San Jose sits in IECC climate zone 3C, which sets the energy-performance bar for any window installed here. Below that, a short list of San Jose's longest-licensed window contractors can turn a spec into an actual installed window.
Licenses checked · California Contractors State License Board
3CIECC climate zone · ENERGY STAR South-Central zone
San Jose's climate zone, in plain terms
San Jose-Sunnyvale-Santa Clara, CA runs a January average near 51°F and climbs to about 71°F by July, a swing that adds up to roughly 2,040 heating degree days most winters, with 764 on the summer cooling side of the ledger.
That load is the actual argument for paying up for a better U-factor in San Jose, separate from anything a brochure claims.
Zone 3C's requirement is the floor; San Jose'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 6.1 mi away.
What FEMA's risk data says about San Jose
Neither rating changes a window's energy label, but both are exactly what impact-resistance and design-pressure ratings are built to answer for a San Jose home.
Ask specifically about design pressure and impact rating for San Jose, not just energy performance, if either risk rating comes back on the high side.
- Strong wind
- Very Low
- Winter weather
- Very Low
Data: FEMA, National Risk Index for Natural Hazards - County-level table, v1.20 (v1.20, December 2025).
Guides to finish before San Jose 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 Jose's longest-licensed window installers
Oldest license first, newest last, pulled directly from the state's file. This list isn't for sale.
- Valhalla Builders INCVerify license
- Le Deit & Sons Glass INCVerify license
- Classic Glass INCVerify license
- A M C Glass CO INCVerify license
- Blossom Hill Glass And Mirror INCVerify license
- Anytime Welding INCVerify license
- Lotus Glass INCVerify license
- Glass 4 LessVerify license
- Interior Glass INCVerify license
- Pro Door And GlassVerify license
- Lincoln Glass & Mirror COVerify license
- Alumawall INCVerify license