Irmo's Climate Data and Its Top-Rated Window Pros
Local risk and climate data for Irmo, SC sit below, translated into plain terms for a window buyer rather than left as raw codes. 8 installers follow that data instead of a license roster, their rank built from Google's star rating and how many people left one. Checked October 2026.
Google Maps ratings checked · How we rank
3AIECC climate zone · ENERGY STAR South-Central zone
What zone 3A means for a Irmo window
Columbia, SC runs a January average near 42°F and climbs to about 79°F by July, a swing that adds up to roughly 3,334 heating degree days most winters, with 1,603 on the summer cooling side of the ledger.
That load is the actual argument for paying up for a better U-factor in Irmo, separate from anything a brochure claims.
Zone 3A's requirement is the floor; Irmo'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 10.5 mi away.
Storm and weather risk around Irmo
FEMA scores Lexington County's winter-weather risk as Relatively Moderate and its flood risk as Relatively Moderate.
Winter risk in Irmo 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 Irmo contractor, not one.
- Hurricane
- Relatively Moderate
- Strong wind
- Relatively High
- 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 Irmo 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.
8 top-rated window installers near Irmo, SC
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.
- Premiere RoofingGoogle reviews
- Indigo State RoofingGoogle reviews
- CMS RoofingGoogle reviews
- Window World of the MidlandsGoogle reviews
- Rennison Roofing and ExteriorsGoogle reviews
- Champion Replacement Windows of ColumbiaGoogle reviews
- Southern Industries Home ImprovementsGoogle reviews
- Pella Windows and Doors Showroom of Irmo, SCGoogle reviews