Round Rock, TX Climate Specs + Top-Rated Window Installers
Round Rock sits in IECC climate zone 2A, which sets the energy-performance bar here no matter who ends up installing your windows. A window license file doesn't cover Round Rock on this site, so Google Maps supplies the 7 ranked names you see below. Checked September 2026.
Google Maps ratings checked · How we rank
2AIECC climate zone · ENERGY STAR Southern zone
Round Rock's climate zone, in plain terms
Round Rock falls in IECC climate zone 2A, and ENERGY STAR separately groups Williamson County into its Southern 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 Round Rock.
A Austin-Round Rock-San Marcos, TX 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 1.8 mi away.
What FEMA's risk data says about Round Rock
Williamson County's hail risk sits at Relatively High and its wildfire risk at Relatively Low, according to FEMA's National Risk Index.
Hail risk matters for glass and screen durability in Round Rock; 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 Round Rock installer before you settle on a product line.
- Hurricane
- Relatively Low
- Strong wind
- Relatively Moderate
- Winter weather
- Very High
Data: FEMA, National Risk Index for Natural Hazards - County-level table, v1.20 (v1.20, December 2025).
Guides to finish before Round Rock 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.
Round Rock's top-rated window installers, by Google
The order below weighs a Google rating against its review count, the same way this site weighs a U-factor against a brochure claim: on the number, not the name. Treat it as a rating, never as proof of a license, bond or HVHZ approval.
- Energy One Windows of AustinGoogle reviews
- Zen Windows AustinGoogle reviews
- Round Rock Siding & TrimGoogle reviews
- Universal Windows Direct Central TexasGoogle reviews
- Bill's Glass & ScreenGoogle reviews
- Round Rock Window Replacement CompanyGoogle reviews
- JJ's Window ServicesGoogle reviews