Interior

• Interior storm windows are mounted on the inside of the window. They require no changes to the existing window, with many versions popping in and out of the frame as needed. Interior storm windows are perfect for historic districts or consumers wanting to preserve the look of their homes as they cannot be seem from the outside. They prevent the temperature-controlled room air from escaping outside. Many interior storm windows are made with weather stripping making them more energy efficient than their exterior counterparts.
  
  

Exterior

• Exterior storm windows are installed on the outside frame of the window. They help prevent outside air from seeping into a home. They are not as energy efficient as interior storm windows because they cannot use weatherstripping. They must have a seepage hole to allow moisture to drain from in between the storm window and main window. Because they have to withstand being exposed to the outside elements, exterior windows are very durable.
  
  

Disposable

• Disposable products are an option for those with limited funds available to put towards purchasing new storm windows. Comprised of sheets made from mylar, polyester or vinyl, they are available in varying degrees of thickness. They are very easy to install and usually come in do-it-yourself kits for homeowners. This option can reduce visibility and does degrade over time, especially with exposure to sunlight. Disposable products are best for budget-conscious consumers and can be a a good choice for windows that are rarely used.
  
  

Glazing

• Window glazing is another option to consider. These windows are composed of two panes of glass or plastic separated by a layer of air and then sealed. Glass panels over better visibility but are heavy and more expensive. Plastic is stronger, lighter and less expensive. Plastic, however, is very prone to scratching, and some materials may become discolored over time.
  
  

Frames

• Frames are a very important factor to consider when choosing storm windows. A frame greatly contributes to a window's insulation factor and maintenance. Wood frames are resistant to heat transfers but they expand and contract according to weather conditions. Most storm windows have vinyl or aluminum frames that slide along tracks. Vinyl is a better insulator but aluminum withstands higher temperatures without warping.