It depends on the type of product and existing windows. Clad products take longer than vinyl windows. We will give you an approximate length of time for install at the time of sale. Most jobs will only take one day.” to “A typical window installation of a whole house of windows takes a day for complete, but there are other factors that may contributed to the extension of the job such as different custom work applications. Depending on the intensity of an installation that involves dry-wall, glass breakage, and other extra work that is an additional to a unit replacement can be a week of installation.