South Portland, ME Climate Specs + Top-Rated Window Installers
ENERGY STAR groups Cumberland County into its Northern zone, the U-factor and SHGC target worth checking against any quote you get in South Portland. Below that spec discussion sit 10 installers, their order set by Google rating, since South Portland is outside this site's window license file. A high rating is worth a look, not a finished decision.
Google Maps ratings checked · How we rank
6AIECC climate zone · ENERGY STAR Northern zone
South Portland's climate zone, in plain terms
South Portland falls in IECC climate zone 6A, and ENERGY STAR separately groups Cumberland County into its Northern 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 South Portland.
A Portland-South Portland, ME 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 1.5 mi away.
What FEMA's risk data says about South Portland
FEMA scores Cumberland County's winter-weather risk as Very High and its flood risk as Relatively Low.
Winter risk in South Portland 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 South Portland contractor, not one.
- Hurricane
- Relatively Moderate
- 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 South Portland 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.
South Portland'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.
- Pella Windows and Doors Showroom of Scarborough, MEGoogle reviews
- Regal Replacement WindowsGoogle reviews
- M & Son ConstructionGoogle reviews
- A-BEST WindowGoogle reviews
- The Maine Window CompanyGoogle reviews
- Portland Glass of PortlandGoogle reviews
- Window World of Southern MaineGoogle reviews
- Maine Windows and DoorsGoogle reviews
- Marvin Design Gallery by EldredgeGoogle reviews
- Paradigm WindowsGoogle reviews