What Duluth Homes Need From a Replacement Window
ENERGY STAR groups St. Louis County into its Northern zone, which is the U-factor and SHGC target worth checking against any quote you get in Duluth. The longest-licensed window contractors based in Duluth are listed below the climate data.
Licenses checked · Minnesota Department of Labor and Industry
7IECC climate zone · ENERGY STAR Northern zone
What zone 7 means for a Duluth window
Moisture and glass performance are handled by different parts of a window's spec sheet, and a Duluth buyer benefits from checking both instead of assuming one implies the other.
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 2.1 mi away.
Storm and weather risk around Duluth
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 Duluth home.
Ask specifically about design pressure and impact rating for Duluth, not just energy performance, if either risk rating comes back on the high side.
- 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 Duluth 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 Duluth
Oldest license first, newest last, pulled directly from the state's file. This list isn't for sale.
- Morins Siding & Window Company INCVerify license
- Les Grumdahl Window & Siding LLCVerify license
- Absalute Vinyl Window & Siding COVerify license