Window Replacement in New York City, New York

In New York City, replacing a window in the same opening may need no Department of Buildings (DOB) permit. The DOB rule on minor alterations lists replacement of existing windows as exempt when the window is not on the lot line, the replacement does not require modifying the existing masonry opening, light and ventilation are not affected and the operable area stays the same (1 RCNY 101-14) ¹. A replacement that does not meet all four conditions falls outside that exemption, and the same table marks replacement of required fire-rated windows as needing a permit ¹.

Three other city rules can apply. A contractor doing home improvement work over $200 on a residential building needs a license from the Department of Consumer and Worker Protection (DCWP) (DCWP tips) ³. The Landmarks Preservation Commission (LPC) says a permit is required to replace windows in designated landmark buildings, and it regulates window replacement on Individual Landmarks and buildings in historic districts (LPC windows fact sheet) ⁵. And the glass should suit a climate with real winters: all five boroughs sit in ENERGY STAR's North-Central zone ⁷.

Do you need a DOB permit to replace windows in NYC?

The DOB's page on facade work says Administrative Code section 28-105.4 sets out work exempt from permit, and that this "does not absolve work from compliance with any other law or rules enforced by the Department" (DOB facade requirements) ². The detail is in 1 RCNY 101-14, Table 3, "Façade Work that may be Exempt from Permit in All Buildings" (1 RCNY 101-14) ¹:

The rule adds that an exemption does not authorize work that violates the construction codes, the New York City Energy Conservation Code or the Zoning Resolution, and does not remove any duty to file with other agencies, the LPC included ¹. Related work such as sidewalk protection or structural work may still need a DOB filing ¹.

When a facade project includes work beyond what may be done without a permit, the DOB page says a Registered Design Professional must submit construction plans for approval before a work permit is issued (DOB facade requirements) ². Questions worth asking before you sign:

• Is any window on the lot line, or is the installer widening, shortening or moving an opening?
• Will the new window open as far as the old one, so the operable area does not change?
• Are any of the windows required fire-rated windows?

The general article on window replacement permits explains why these rules vary from city to city.

Who may do the work: the DCWP license

DCWP says a person or business must hold a Home Improvement Contractor license to do work that costs more than $200 on any residential building in NYC; it does not cover new home construction, plumbing or purely electrical work (DCWP tips) ³. The same page says:

• The contractor must give you a written contract that you both sign, with a separate Notice of Cancellation form ³.
• Pay no more than 25% of the total contract amount upfront to get the work started ³.
• Before you sign, the contractor must give you written notice about all permits the work requires ³.
• If a contractor holding a DCWP license did not complete the job or owes you money, you may be eligible for repayment from the Home Improvement Contractor Trust Fund; you are not eligible if you used an unlicensed contractor ³.

To check, use DCWP's Search Business tool, which shows whether an individual or business holds a DCWP license and needs no account (DCWP license check) ⁴. Does the license number on your quote match the business name in the search? Does the contract name the same business? The guide on how to choose a window installer covers references and warranties.

Landmarks: windows in designated buildings

The LPC regulates window replacement on Individual Landmarks and on buildings in historic districts, and its fact sheet says an LPC permit is required to replace windows in designated landmark buildings (LPC windows fact sheet) ⁵. To qualify for staff-level approval, new windows must match the historic windows to varying degrees depending on the facade, building type and size; proposals that do not meet those criteria go to the full Commission at a public hearing ⁵. The fact sheet says the majority of window replacement proposals LPC reviews meet the requirements for staff-level approval, and that applications go through Portico, the LPC's online portal ⁵.

Not everything needs an LPC permit. The fact sheet says most repairs, retrofits and routine maintenance, such as clear glass replacement, caulking and weatherstripping, do not, and neither do interior storm windows with clear glazing that do not need mullions, muntins or wide frames visible from the exterior ⁵. Exterior storm windows with clear glazing do need one ⁵. If your building is landmarked, ask the installer whether they have worked through an LPC approval before, and who prepares the drawings. The article on storm windows explains that option.

Climate and glass for New York City

ENERGY STAR places New York County (Manhattan) in its North-Central zone, and its county list puts the other four borough counties (Bronx, Kings, Queens and Richmond) in the same zone (ENERGY STAR climate zone finder) ⁷. In that zone, Version 7.0 criteria call for a U-factor of 0.25 or less and a solar heat gain coefficient (SHGC) of 0.40 or less, and every ENERGY STAR window must meet an air leakage limit of 0.3 cubic feet per minute per square foot (ENERGY STAR criteria) ⁶.

NOAA's 1991-2020 normals for Central Park show why both numbers matter. The winter (December to February) average temperature is 36.2°F, the summer (June to August) average is 75.2°F, and normal snowfall is 29.8 inches a year ⁸. The station logs about 4,550 heating degree days and about 1,220 cooling degree days a year, so heating is the larger load, but summer sun counts too ⁸.

U-factor measures how fast heat moves through the whole window; lower insulates better. SHGC is the share of the sun's heat that passes through the glass. The articles on U-factor and low-E glass go further, and the energy-efficient windows explainer covers the labels.

What windows cost in NYC

This article does not quote a New York City price; the survey figure here is national. Fixr reports about $800 per window, typically $450 to $1,200 (updated January 21, 2026) ⁹. The window replacement cost guide sets several surveys side by side and explains what moves the price.

Getting quotes

Ask each installer for the same window, the same glass and the same installation method in writing, plus the DCWP license number and the permit notice. The article on how to compare window quotes gives a line-by-line template. When you are ready, you can compare quotes from window installers.

About these figures

• ¹ Official record: 1 RCNY 101-14, Table 3 (window replacement exempt under four conditions, fire-rated windows require a permit, sills and inner glass exempt) and subsection (c) on the Energy Conservation Code and other agencies, checked October 26, 2026.
• ² Official record: DOB facade requirements page (AC 28-105.4 exemptions; a Registered Design Professional submits plans when facade work goes beyond what may be done without a permit), checked October 26, 2026.
• ³ Official record: DCWP hiring tips (license for work costing more than $200 on residential buildings, written contract and Notice of Cancellation, 25% upfront limit, permit notice, Trust Fund eligibility), checked October 26, 2026.
• ⁴ Official record: DCWP Check License Status page and its Search Business tool, checked October 26, 2026.
• ⁵ Official record: LPC windows fact sheet dated November 20, 2024 (permit to replace windows in landmark buildings, staff-level approval, public hearing, Portico, repairs and storm windows), checked October 26, 2026.
• ⁶ Official record: ENERGY STAR Version 7.0 window criteria (North-Central U-factor 0.25, SHGC 0.40, air leakage 0.3), checked October 26, 2026.
• ⁷ Official record: ENERGY STAR county climate zone finder (New York, Bronx, Kings, Queens and Richmond counties in North-Central), checked October 26, 2026.
• ⁸ Official record: NOAA NCEI 1991-2020 normals for Central Park (winter 36.2°F, summer 75.2°F, snowfall 29.8 inches, heating degree days 4,553, cooling degree days 1,222), checked October 26, 2026.
• ⁹ Reported: Fixr national per-window cost, about $800, typically $450 to $1,200, updated January 21, 2026, checked October 26, 2026.