The heat lost through windows during cold weather installation is minimal. With 7,000+ installations completed since 2011, Coastal Windows & Exteriors is an InstallationMasters-certified window installer and family-run, woman-owned exterior remodeling company serving 730+ towns across Massachusetts, New Hampshire and Maine. Each opening is exposed only briefly while that unit is swapped.
What to Expect on Installation Day
- Brief openings: Each opening is exposed only while that unit is swapped, so rooms cool briefly. Get a free estimate this fall to plan your day.
- Room by room: Crews typically work one room at a time, so the rest of the home stays warm.
- Fall comfort: Installing in fall means milder outdoor air while openings are exposed.
- Small surface: Windows make up about 8% of a home’s exterior surface area, per PNNL.
- Better glass: Triple-pane glass reaches a U-value of 0.20 to 0.30. Lower U-values mean less warmth escapes.
A few simple steps keep things cozy. Close interior doors to the rooms being worked on. Nudge your thermostat up a degree or two on install day.
Staying Comfortable During Your Window Project
Top Recommendation: A free in-home estimate lets us plan your install room by room. Book yours this fall.
Better Glass: Triple-pane units hold heat better, with lower U-values than double-pane.
Smart for Fall: Milder fall air keeps rooms more comfortable than a winter install.
Request a free windows estimate from Coastal Windows & Exteriors.
Browse our complete windows FAQ guide from Coastal Windows & Exteriors.
Explore the Coastal Windows & Exteriors Windows Exterior Remodeling Home Improvement Help Center.
Still have questions about What Happens to My Home’s Heat During a Window Replacement — Will It Get Cold Inside? See the areas we serve and talk to your local windows contractor.
Last Updated: September 2026
Sources:
- Windows make up about 8% of a home’s exterior surface area but account for much of its heat loss. Pacific Northwest National Laboratory How Triple-Pane Windows Stop Energy and Money From Flying Out the Window, national laboratory research on window heat loss and efficiency. (2022)
- Triple-pane glass reaches a U-value of 0.20 to 0.30 versus about 0.30 to 0.45 for double-pane. China North Glass Double vs. Triple Pane Insulating Glass, technical comparison of double and triple pane efficiency ratings. (2025)
