Manufacturers do not sell to the public. Here is the chain between the factory and your wall, what each seller is responsible for, and why a supplier who installs is the one you want.
Most people buy windows once or twice in a lifetime, and most start in the wrong place: the window aisle of a home-improvement store. It seems logical. Windows are a product, the store sells products, and there is a price on the shelf. But a window is not finished when it is bought. It is finished when it is in the wall, square, sealed and working, and almost everything that decides whether that happens lies outside the box it came in. This article explains how windows are actually sold, who each seller is and is not responsible for, and why the person you want is a window supplier who also measures, installs and services what they sell.
Window manufacturers, with few exceptions, do not sell to the public. They sell through a chain: dealers, lumberyards, home-improvement stores and specialist suppliers. Each link in that chain sells you the same kind of box. What differs is what happens around the box: who measures the opening, who is responsible if the size is wrong, who installs, who seals the joint, and who comes back when a sash sticks two winters later.
A direct window supplier is a company that deals with the manufacturer directly and with you directly, with nobody in between, and that takes responsibility for the whole opening. That is what Alex GC is. If you are looking for a window supplier in Brooklyn, or anywhere in New York City and New Jersey, the questions at the end of this article will tell you quickly which kind of seller you are talking to.
The route is called the channel of distribution, and for windows it has four common forms.
| Where you buy | Who measures | Who installs | Who services it later |
|---|---|---|---|
| Home-improvement store | You, or a third party the store sends | You, your contractor, or a subcontractor arranged by the store | The store's process, then the manufacturer |
| Lumberyard or building-supply dealer | Your contractor | Your contractor | Your contractor, if they are still reachable |
| Window dealer or showroom | You or your contractor | Not the dealer | The manufacturer's warranty desk |
| Direct window supplier and installer | The supplier | The supplier | The supplier |
The window in each row can be exactly the same product from the same factory. The difference is how many separate parties stand between the order and the finished opening, and whether any one of them answers for the result.
It surprises people that they cannot simply call a window factory and order. There are good reasons.
So the manufacturer sells to dealers and installers, and you buy from one of them. The question is which.
Stores such as Home Depot and Lowe's sell windows in two ways: a limited range of stock sizes on the shelf, and special orders placed at a desk. For a simple job, such as a standard-size window in a garage or a shed, or for an experienced owner doing their own work, that can be perfectly reasonable.
For anything else, consider what the store is and is not.
None of this is a criticism of the stores. They are built to sell materials. A window in a New York building is a small construction project, and it needs someone who treats it as one.
Lumberyards and building-supply dealers are the traditional source of windows for contractors, and many carry very good brands. Their business model is trade supply: a contractor who knows exactly what they need phones in an order, and the yard delivers it.
That model has consequences for anyone who is not a specialist. Many yards prefer not to take window orders from people who do not work with the product every day, and they are right to be cautious: one wrong digit on a custom order produces a window nobody can use and nobody will take back. The yard will not measure your openings. It will not install. Its responsibility ends when the correct box, as ordered, leaves the truck. If the general contractor who ordered it has finished the job and moved on, there may be nobody to call.
Between the yard and the installer sits the dealer or showroom that represents one or two manufacturers. A good showroom is useful: you can see and operate the windows. But a dealer who only sells is still only selling. They do not look at your wall. They are not there on installation day. They do not service the window; for that they refer you to the manufacturer's warranty department, which will cover a defective part and nothing that comes from the way the window was measured or fitted.
The pattern in all three routes is the same. The seller's interest ends at the sale, and the risk of everything after it, sizing, installation, sealing, adjustment and service, passes to you.
A direct window supplier buys from the manufacturer and sells to the building owner or contractor with no one in between, and takes on the work the other sellers leave out.
One company, one contract, one phone number. If something is wrong, there is no argument about whose fault it is.
This is the single most important fact about buying windows, and the one buyers learn too late. A window made to your size, in your color, with your glass, has no other buyer. No manufacturer, dealer or store takes it back because it does not fit, because the color looks different in daylight, or because the plan changed. The only protection is to get the order right before it is placed, which is why who measures matters so much.
Standard sizes are a different case, with different rules. We are preparing a separate article on standard window sizes and return policies. For how early to order, see when to order windows.
A window bought in a box does not include what makes it work in the wall. Every opening also needs installation materials, and choosing the wrong ones is how good windows end up leaking.
A store sells you a window and leaves the rest to you. As a supplier we provide both. The installation materials our crews use, including silicone sealants, backer rod and shims, are available by the case or singly from our supply business, NYCE Glass Supplies, with delivery across New York City. Contractors who install their own windows can order the window package and the materials for the joint together. See also waterproofing and how a window is installed.
Every window needs attention eventually. Sashes need adjusting after the first season as a building settles. A glass unit gets broken. A handle or a lock wears. Gaskets age. With a store or a sales-only dealer, service means finding the receipt, calling a warranty line and waiting to learn whether your problem counts as a defect.
A supplier who installed the windows has the order on file: system, color code, glass make-up and size of every unit. Replacement glass can be ordered without re-measuring. Hardware matches. And because the same company is responsible for the installation, adjustment is simply done. When you compare prices, ask each seller what window service they provide and for how long; the answers differ more than the prices do.
Local knowledge is part of the product. A window supplier in Brooklyn deals every week with brownstone openings that are out of square by an inch, landmark districts from Brooklyn Heights to Park Slope, pre-war apartment buildings with steel lintels, new mid-rise buildings with sound requirements on the avenue side, and streets where a delivery truck has ten minutes at the curb. None of that appears in a catalog.
We supply windows throughout Brooklyn, Queens, Manhattan, the Bronx and Staten Island, where we are based at 7 Beach Street, and across New Jersey. Recent Brooklyn work includes 126 Washington Avenue, Clinton Hill (Marvin double-hungs on a rebuilt townhouse), 343 Hoyt Street, Carroll Gardens (Pella in a historic district), 185 Van Dyke Street, Red Hook (custom arched aluminum) and 408 Lefferts Avenue (a complete package for a new six-story building). See windows, doors and glass in Brooklyn.
Not every customer wants installation. General contractors, builders and installers with their own crews buy from us supply-only, at trade pricing, and get what a yard does not give them: someone who checks the schedule against the openings, flags a size the system cannot make, produces shop drawings and supplies the installation details and materials. See material supply and wholesale windows for contractors.
A seller who answers all seven without hesitation is a supplier. A seller who answers the first with "you do" is selling boxes.
To be fair: if you need one standard-size window for a simple opening, you are comfortable measuring and installing it yourself, and the building has no special rules, a home-improvement store is quick and inexpensive. For everything else, a house full of windows, an apartment, a landmark, a custom size, a new building, the cheapest box is rarely the cheapest window once it is in the wall. Buy from the people who will put it there and answer for it.
A company that buys windows straight from the manufacturer and sells them straight to the owner or contractor, with no dealer in between, and that measures, orders, delivers and usually installs and services them.
Generally no. Most window manufacturers sell only through dealers, suppliers and installers, because windows are made to order and need trained ordering, local delivery and proper installation.
The box may be cheaper for a stock size. The finished opening often is not, once measuring, installation, sealing materials, trim and the risk of a wrong custom size are counted.
No. A window made to your size, color and glass cannot be resold, so no seller takes it back. Measure and confirm everything before the order is placed.
Many do not. A sales-only dealer or lumberyard supplies the product; measuring, installation and service are left to you or your contractor.
Sill pan or membrane and flashing tape, shims, anchors or clips, low-expansion foam, backer rod and a neutral-cure finish silicone.
Alex GC supplies and installs windows across Brooklyn and the rest of New York City and New Jersey, from 7 Beach Street, Staten Island. Call 929-235-1233.
Adjustment of sashes and hardware, replacement glass units, new gaskets and locks, and resealing, ideally from the company that supplied and installed the windows.
Window Replacement Material Supply Choosing a New Construction Window Supplier Wholesale Windows for Contractors When to Order Windows Brooklyn Windows, Doors & Glass All News
About this page. Written by Alex GC Inc. d/b/a Alex Glass Construction and reviewed before publication by Aleksandr Chernovolenko, Managing Partner, with our design and estimating lead and a field foreman. Our foremen hold the NYC DOB Site Safety Training supervisor card and our crews the 40-hour worker card; we are certified to fabricate, install and service Alutech and Everest aluminum systems. Facts are drawn from our own projects, manufacturer test data and the applicable codes; where we are giving an opinion, we say so. Last reviewed September 2026. Credentials
Send photographs of the openings with rough sizes, or the window schedule. We will measure, recommend the right product and quote it supplied or supplied and installed.
