Across 633 permits filed since 2025-04-30, the median is $20,000; half of projects fall between $10,043 and $43,706. Figures are permit valuations reported to building departments. National cost guides answer this question with averages from other markets; these numbers are what homeowners in Westchester County, NY actually reported when they pulled permits.
Recent filings
- ALTERATION TYPE II of an existing single-family dwelling. The work includes removing a window in the existing bedroom and converting the space into a closet and converting (1) living room window into a door. No changes to the footprint or bTown of Lewisboro · 2026-10-28$350,000
- INSTALL NEW EXTERIOR SIDING AND NEW WINDOW CAPPING FOR LEVEL II ALTERATIONS TO INCLUDE THE REMOVAL AND REPLACEMENT OF OF SIDING THAT COMPLIES WITH ASTM D3679 FOR A RESIDENTIAL BUILDING. ALL WORK TO BE DONE PER MANUFACTURERS' SPECIFICATIONSGreenburgh · 2026-10-28$24,000
- Replace 1 existing window with no structural changes.Village of Bronxville · 2026-10-28$4,300
How to read these numbers
Permit valuations are the project cost the applicant reports to the building department. They skew slightly low — nobody rounds up for the permit fee — and scope varies, so the middle-half range is the honest picture: half of all window replacement permits in Westchester County, NY came in between $10,043 and $43,706. We exclude permits under $1,000, jobs filed as whole-house construction, and counties whose building departments don't reliably report valuations.
Same project, other places
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