The easiest way to immediately identify your windows is by locating the name of the manufacturer itself on the product. Some companies, like Acorn, Jeld-Wen, Biltbest, Caradco, Truth, EntryGard, Hurd and others may stamp their name on the window hardware ( original proprietary parts ) like the handles, cranks, sash locks, operator covers, other hardware. Look carefully when inspecting hardware: many companies buy their hardware from other manufacturers and this hardware can be found for a multiple of brands of windows like - ALENCO, ALSCO ANACONDA, ALWINSEAL, AMACOR; In the same way, if window parts have ever been replaced, they might not have been made by the same company that created the OEM Units.
Other companies, like Marvin, Keller, Malta, Oldach, Outlook, Kolbe & Kolbe, Andersen, Anderson, Arcadia, Bayform, MilGard, and others have their information stamped in the spacer bar channel. (The spacer is in between the two panes of glass on an insulated unit in your window sash ) and runs clear around the edge of the glass - Brands like Thermalgard, Traco, Weathercraft, Wenco, Andersen, Shelter and Windsor - to name a few .. etch their names in the corner of the glass or into the spacer bar. There are also some companies that don't put their company name anywhere on the window. Crestline, Vetter, Columbia, Craftline, Crestline, Crossly, Dayton and others are known to have done this. Sometimes you will find a string of letters and numbers ( stampings ) on their products. Unless you know exactly what these letters and numbers mean, it can be impossible to determine what brand of window you have.