Londonderry, NH Climate Specs + Top-Rated Window Installers
Londonderry sits in IECC climate zone 5A, which sets the energy-performance bar here no matter who ends up installing your windows. A window license file doesn't cover Londonderry on this site, so Google Maps supplies the 5 ranked names you see below. Checked October 2026.
Google Maps ratings checked · How we rank
5AIECC climate zone · ENERGY STAR Northern zone
Londonderry's climate zone, in plain terms
Londonderry falls in IECC climate zone 5A, and ENERGY STAR separately groups Rockingham 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 Londonderry.
A Boston-Cambridge-Newton, MA-NH 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 5.5 mi away.
What FEMA's risk data says about Londonderry
FEMA rates Rockingham County's hurricane risk as Relatively Moderate and its wind risk as Relatively Moderate.
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 Londonderry home.
Ask specifically about design pressure and impact rating for Londonderry, not just energy performance, if either risk rating comes back on the high side.
- Hurricane
- Relatively Moderate
- Strong wind
- Relatively Moderate
- 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 Londonderry 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.
Londonderry'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.
- Fiori Construction LLCGoogle reviews
- DeFrancesco Quality Roofing, Siding and WindowsGoogle reviews
- Window AuthorityGoogle reviews
- MKJ ConstructionGoogle reviews
- Harvey Windows + DoorsGoogle reviews