Washington, UT Climate Specs + Top-Rated Window Installers
Washington sits in IECC climate zone 3B, which sets the energy-performance bar here no matter who ends up installing your windows. A window license file doesn't cover Washington on this site, so Google Maps supplies the 10 ranked names you see below. Checked October 2026.
Google Maps ratings checked · How we rank
3BIECC climate zone · ENERGY STAR South-Central zone
What zone 3B means for a Washington window
St. George, UT runs a January average near 41°F and climbs to about 87°F by July, a swing that adds up to roughly 3,205 heating degree days most winters, with 2,416 on the summer cooling side of the ledger.
That load is the actual argument for paying up for a better U-factor in Washington, separate from anything a brochure claims.
Zone 3B's requirement is the floor; Washington'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 6.6 mi away.
Storm and weather risk around Washington
FEMA scores Washington County's winter-weather risk as Relatively Low and its flood risk as Relatively High.
Winter risk in Washington 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 Washington contractor, not one.
- Strong wind
- Very Low
- 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 Washington 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.
10 top-rated window installers near Washington, UT
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.
- Glass Doctor of St. GeorgeGoogle reviews
- Sun City GlassGoogle reviews
- Epic Windows + DoorsGoogle reviews
- Dixie GlassGoogle reviews
- Jones Paint & Glass IncGoogle reviews
- Desert Sky Daylight LLCGoogle reviews
- St George Windows Doors & MoreGoogle reviews
- Legacy Windows LLCGoogle reviews
- D2 Building SolutionsGoogle reviews
- All Purpose Windows and DoorsGoogle reviews