Identifying the brand of old windows or doors can sometimes be challenging, especially if there are no visible markings or labels. However, there are several methods you can try:

1. Manufacturer's Markings: Look for any labels, stickers, or markings on the window frame, sash, or hardware. These markings often include the manufacturer's name, logo, or product information. Check all visible surfaces, including the corners and edges of the frame.
2. Inspect the Glass: Sometimes, manufacturers may etch their logo or brand name onto the glass itself, usually in one of the corners. Look closely at the edges of the glass panes for any inscriptions.
3. Research Common Brands: If you're unable to find any markings, research common window and door brands from the time period when your windows were installed. This may help you narrow down the possibilities based on the style, design, and features of your windows.
4. Consult Documentation: If you have any documentation related to the installation or purchase of the windows, such as receipts, invoices, or warranty information, check for references to the manufacturer or brand.
5. Contact a Professional: If you're still unable to identify the brand, consider contacting a professional window installer or contractor. They may have experience with a wide range of window brands and may be able to recognize the manufacturer based on the design and construction of the windows.
6. Online Forums or Communities: Posting clear photos of your windows in online forums or communities dedicated to home improvement or vintage home restoration may also help you identify the brand. Other enthusiasts or professionals may recognize the windows based on their appearance.
7. 7.  If you're searching for the window or door brand of older windows and you have access to the American Architectural Manufacturers Association (AAMA) sticker, here's how you can proceed:
8. Manufacturer's Name: The AAMA sticker typically contains information about the manufacturer, including the company name or logo. Look for any text or logos that indicate the manufacturer's identity. Sometimes, the brand name may be abbreviated or appear in a stylized format, so be sure to examine the sticker closely.
9. Product Information: The AAMA sticker may also include specific product information, such as model numbers, series names, or manufacturing codes. This information can be useful for identifying the exact product line or series from the manufacturer.
10. Certification Markings: The AAMA sticker may feature certification markings indicating that the window or door meets certain industry standards for performance, quality, or energy efficiency. These markings can help confirm the authenticity of the product and may provide additional clues about the manufacturer.
11. Research Online: Once you have gathered information from the AAMA sticker, you can search online using the manufacturer's name, product information, or any other details obtained from the sticker. Many window manufacturers have websites where you can find product catalogs, historical information, and contact details.



By carefully examining the AAMA sticker and conducting thorough research, you should be able to identify the brand of your older windows or doors. If you encounter any difficulties, don't hesitate to seek help from professionals or industry organizations.