In the last decade, there seems to have been a large number of all-vinyl sliding doors installed in our area. Most have been manufactured by virtually unknown companies who sell to builders’ supply distributors for resale to independent contractors looking for a product they can sell for less to the consumer. Even some major manufactures have developed an all-vinyl line to compete. The selling features are… 1. Vinyl is a good insulating material. 2. They are cheap. Our company is usually called upon to maintain sliding patio door systems that have been in service for 25-35 years or more.