What Thousand Oaks Homes Need From a Replacement Window
Thousand Oaks sits in IECC climate zone 3C, which sets the energy-performance bar for any window installed here. Below that, a short list of Thousand Oaks'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
What zone 3C means for a Thousand Oaks window
Thousand Oaks falls in IECC climate zone 3C, and ENERGY STAR separately groups Ventura County into its South-Central zone for window certification.
Those two numbers, not the brand on the box, set the U-factor and SHGC worth checking on any quote you get in Thousand Oaks.
A Oxnard-Thousand Oaks-Ventura, CA contractor who can't name either one on request is worth a second question before you sign.
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 12.1 mi away.
Storm and weather risk around Thousand Oaks
Ventura County's hail risk sits at Relatively Low and its wildfire risk at Relatively High, according to FEMA's National Risk Index.
Hail risk matters for glass and screen durability in Thousand Oaks; wildfire risk matters more for the frame material and nearby vegetation than for the glass itself.
Either way, it's a reasonable question to bring to a Thousand Oaks installer before you settle on a product line.
- Strong wind
- Relatively 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 Thousand Oaks 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 Thousand Oaks
Oldest license first, newest last, pulled directly from the state's file. This list isn't for sale.
- Arrow Glass Of Thousand OaksVerify license
- Valencia Glass CompanyVerify license
- JS Glass & Mirror INCVerify license
- Window Design GroupVerify license
- Ca Glass Installation INCVerify license
- KG GlassVerify license
- Inflow Window LLCVerify license