Polyester can be made into thread , yarn or clothes . Woven into synthetic fabrics, they are often used to make clothes and home furnishings. These include shirts, trousers, pants, jackets, hats, bedding and upholstered furniture. Polyester fiber is used as cushioning and insulating material in pillows, comforters and upholstery padding. It can be used in curtains to insulate windows and keep heat indoors. Polyester is used to make insulating carpet.