The wide variety of fabrics and brands on offer can be overwhelming. To make sense of the products available to you, you would first want to get an understanding of the different fabrics and how they perform under different conditions.
Vinyl covers are what you would call your “bang for the buck” product. They are not ordinarily sold as a pure vinyl cover, but will have a laminated fabric on the inside. Most often this liner fabric is intended to provide scratch free protection to the furnishings being covered, and also adds resilience to the product which has relatively low tear resistance on its own. By nature vinyl’s are less weather resistant than other fabrics and do not handle extremes of temperature very well. This of course does not indicate that it is a poor choice, dependent on ones needs and budget. Most plastic covers will have a UV protectant applied to the surface to improve longevity. To add to the value for money attraction of the product, manufacturers offer very liberal warranty coverage on them. Because the fabric is not breathable, you want to make sure that air has the ability to pass under the cover. The lack of air movement could result in the formation of mildew.
Another fabric widely used in the manufacture of outdoor furniture covers is Polyester. This is a synthetic product that is used in the manufacture of a wide variety of products ranging from hoses to power belts, soda bottles and of course furniture covers. The big advantage of using this type of product is its ability to handle high levels of heat while retaining its soft feel. It cleans easily and like vinyl requires that airflow is possible under the fabric to prevent mildew forming. You will often see vents sewn into the fabric to assist with air movement. These covers are treated to provide a water resistance which is not inherent in the fabric. Fabric density or weight varies in the fabrics used for the outdoor covers with the better quality covers being manufactured from a 600 denier polyester. This measurement refers to the number of twists per inch in the polyester and the 600 provides the best balance between feel and performance for covers.