Local research · updated July 2026
Replacement Windows in Williamsport, Pennsylvania
Williamsport sits on the Susquehanna in north-central Pennsylvania — Little League World Series fame, freeze-thaw winters, river flooding, Marcellus-era growth, and historic Millionaires' Row stock. Of the city's housing units, 84.6% predate 1980 and the median year built is 1938. Lycoming County is ENERGY STAR Northern / IECC 5A: ultra-low U-factor is the heating priority. Replacement here is cold-climate glass on mixed historic and growth openings.
Short answer
In Williamsport, a standard replacement window (double-hung, casement or slider) typically costs $515–$2,945 installed. Bay and bow windows run $2,585–$8,275+, and a sliding patio door $1,550–$5,170. Frame material and the glass package decide where a project lands in that range.
Planning ranges built from NREL and BLS cost data, localized to Williamsport with the BEA Regional Price Parity for Williamsport, PA (2024). How we estimate →
84.6%
of Williamsport homes were built before 1980, the era of single-pane and early aluminum windows
Source: U.S. Census Bureau, 2019–2023 ACS 5-Year Estimates
1938
median year built across Williamsport's 13,137 housing units
Source: U.S. Census Bureau, 2019–2023 ACS 5-Year Estimates
U ≤ 0.22
the ENERGY STAR v7.0 number that matters most in the Northern zone
Source: EPA ENERGY STAR v7.0
Window installers in Williamsport
Compare companies serving Williamsport. Request a free, no-obligation quote and we route it to the company or a vetted local installer.
| Company | Location | Request a quote |
|---|---|---|
 4.8 · 200,000+ reviews | Montoursville, PA | Get a quote → |
| 1Window World of GSVWindow World | Montoursville, PA | Get matched → |
| 2Window World of MifflinburgWindow World | Mifflinburg, PA | Get matched → |
Renewal by Andersen of North Central PA
4.8 · 200,000+ reviewsMontoursville, PA showroom · serving the Williamsport metro
Full-service manufacturer and installer, transferable warranty, local crews. Why it's our Top Pick
Get a quote →Listings compiled from manufacturer dealer locators and public business records. Premier and Sponsored Partners pay for placement and are labeled as such; star ratings shown are reported by the partner, with the source and date beside them. See our advertising disclosure. Contacting a company shares your details with it (or a vetted local installer) so it can reach you about your project.
Are you a window company? Claim your listing to take quote requests from Williamsport homeowners directly.
What drives window decisions in Williamsport
- Northern / 5A: U-factor ≤ 0.22 under ENERGY STAR v7.0.
- Historic and Marcellus-era stock: two different job types.
- Susquehanna flooding is parcel-specific — check FEMA maps.
- Pennsylvania utility pathways; 25C expired.
Replacement windows & doors by type in Williamsport
Local cost ranges and Northern-zone efficiency guidance for each window and door style, specific to Williamsport homes:
Ranges localized to Williamsport's cost level: national planning ranges shifted by the BEA Regional Price Parity for Williamsport, PA (92.4, U.S. = 100; 2024). How we estimate local costs →
Efficiency requirements for Williamsport's climate
Williamsport sits in the ENERGY STAR Northern zone (IECC zone 5A (cold, moist), Lycoming County). Under the v7.0 specification, qualifying windows need a U-factor of 0.22 or lower with a solar heat gain coefficient (SHGC) of at least 0.17. Heating-dominated climate: the window must hold heat in (very low U-factor) while still letting some free solar warmth through in winter (minimum SHGC). Equivalent-performance tradeoffs allow U-factors of 0.23–0.26 when paired with progressively higher solar gain.
Not sure what these numbers mean? Read our plain-English guide to U-factor and SHGC.
What replacement windows cost here
North-central PA pricing is generally moderate. Historic openings raise spreads. Federal 25C is gone. Itemize every bid.
For a breakdown by frame material and install type, see our full cost guide.
Rebates & incentives in Pennsylvania
The federal window tax credit (25C) ended for projects placed in service after December 31, 2025. If your windows were installed in 2025, you can still claim it on your 2025 return — but for new projects there is no federal window credit. State and utility programs are now the main source of window incentives.
Pennsylvania has been standing up IRA Home Energy Rebate programs through the state; windows can qualify as part of a modeled whole-home efficiency retrofit. Verify current availability before promising rebate money.
- Act 129 utility efficiency programs (PECO and others). Pennsylvania's Act 129 requires electric utilities such as PECO to run energy-efficiency programs; audits and envelope work are incentivized, with windows generally part of a broader package. (PA PUC Act 129; PECO / PGW program pages)
Pennsylvania enforces the statewide Uniform Construction Code (UCC) based on the IECC; Philadelphia permits through Licenses & Inspections, and its Historical Commission reviews designated historic properties.
Replacement windows in nearby metros
Not in Williamsport proper? These nearby markets carry the same local research: housing-age data, climate-zone specs, and current rebate status for each city:
Williamsport window replacement FAQ
›Do I need a permit to replace windows in Williamsport?
Usually yes for full replacement. City of Williamsport Codes. Historic districts may add design review. Confirm the installer pulls the permit.
›What efficiency numbers should windows hit?
ENERGY STAR Northern and IECC 5A: U-factor 0.22 or lower under v7.0. Heating priority. Read the NFRC label.
›Are there rebates?
Federal 25C expired December 31, 2025. Check Pennsylvania utility efficiency programs.
›Historic homes on Millionaires' Row — restore or replace?
Sound wood plus storms can work where design review allows. Full replacement when sashes are rotted or seals have failed systemically.
Sources
- — U.S. Census Bureau, American Community Survey 5-Year Estimates (B25034, B25035)
- — EPA ENERGY STAR Version 7.0 Residential Windows specification
- — DOE/PNNL IECC climate zone assignments by county
- — NWS State College; FEMA flood maps; NOAA winter climatology
- — IRS, 25C Energy Efficient Home Improvement Credit (P.L. 119-21)