Buying Plexiglas for your interior storm windows
Plexiglas is one brand of acrylic sheet, but almost any brand will do. Acrylic/Plexiglas is the perfect solution for Window Savers, because it doesn't yellow, is sturdy, has great insulating properties, and blocks noise very well.
Home Centers and plastics distributors both have good prices, but distributors have the best selection and cutting equipment. You will find them listed under “Plastics—Sheet" or Acrylic Sheet or similar listing. Acrylic varies in price from place to place, so it is a very good idea to contact all of your suppliers in your region before you buy. The usual practice is to give your supplier your cutting list by phone, fax, or email, and then they will quote your price.
Lexan polycarbonate also works and is tougher than acrylic, but it scratches more easily, and costs twice as much. It is not usually needed unless you live beside a golf course or fear vandalism.
Measuring for Plexiglas
Measuring methods are the same for both types of mounts.
Make your Plexiglas 1-1/8" greater than the distance between opposite inner edges of the 5/8" steel mounting strips. If weather strip is to replace the lower cleat, measure down to the sill and add 1/2".