A new set of windows can liven up the appearance of your house and add value to your property in the long run. New windows will also increase your insulation.The cost of windows will depend on the type, dimensions, materials used, security features, the complexity of the installation, and, of course, the number of windows needed. Number of Windows Generally, the more windows you need to install, the more expensive the installation price..The cost to Install Replacement Windows starts at $ $ per window, but can vary significantly with site conditions and options. Get fair costs for your SPECIFIC project requirements..Replacing a window costs an average of $ to $ per window. Thisumes that the replacement window is going into an existing and structurally sound frame on a ground floor. Replacing windows in a typical three bedroom, single story home with ten windows can cost from $, to $,. This cost can easily double for a two story home..