The type of installation and frame style used to determine whether a window is Retro Fit or Replacement is referred to as Retro Fit or Replacement. This sort of window is made to fit into a pre-existing window frame. This type of installation can usually be completed in one day with no damage to the external or interior walls. The exterior flange of retro fit windows allows them to cover your previous window frame. A lifetime warranty on the installation is provided with a professional installation completed by our factory trained and qualified installers. We have a variety of top manufacturers to pick from, so we can provide you with multiple options and prices to meet your requirements. So give us a call today!