The vintage of your window or patio door is determined by the manufacturing date.  You can find the manufacturing date in the Andersen logo etched into the glass or on the Product Identification Label.

The product id label shown below shows the manufacture date of August 6, 2008. Andersen began putting Product Identification labels on windows & patio doors in 2007. For details on where the product identification label on products is located view this Product Label Identification Guide.

The glass logo example below shows a manufacturing date of 1-06 etched in the glass.  This window or patio door was manufactured during the first quarter of 2006. This logo also determines the glass type.