On average, full frame replacement costs 10-15% more than a retrofit installation
In a retrofit installation, new windows are inserted into existing frames. This is ideal in preserving the look of a window and is a good option if the frame or structural components are not damaged or aged.
In a full frame installation, the window is replaced with new brickmoulds and casing. This kind of installation is also the best way to ensure the longevity and proper efficiency of new windows.
The type of installation is a big determining factor in the final cost of your windows.