Anyone with windows in a home or business can gain greater efficiency with an interior storm window.  These uniquely designed insulators seal up the window, skylight, fan, or fireplace opening to block out drafts.  There are something like 50 million homes in the United States with single pane glass that could reduce their utility expenses and get a pretty quick payback on their invesment comfort.  Our particular design uses a magnetic seal, which acts like a gasket providing "give" when temperatures are increasing and decreasing in certain seasons.  Insulating your existing windows keeps your HVAC from working so hard and extending it's useful life.