Most of the windows and doors supplied by Window Works are made by Marvin. This means that every Marvin product you buy from us comes with an unbeatable Marvin warranty that covers any defects from manufacturing, materials, and workmanship for ten years. The warranty begins from the date of purchase. Marvin has another warranty that runs up to 20 years on insulated glass. This warranty protects the glass against visible obstruction caused by a failure or the air seal of the glass. Visit their website for more details.