There are two different window installation methods — pocket installation and full-frame installation.
With a pocket installation, only the sash of the old window is removed and the new window is then placed into the existing frame. While this installation process tends to be quicker, and typically takes about an hour per window, pocket installation does limit you to replacing only within the existing opening.
Full-frame installation, however, can change the opening to accommodate new window shapes and sizes. With full-frame installation, installers remove the entire window — frame, trim, and all — and put a completely new window with new frame, trim, and insulation in its place. Because this method involves work on both the inside and outside of the home, it is more time- and labor-intensive.
A full-frame window installation includes removing and replacing the interior and exterior trim. During the process, the entire process everything is removed.
You should replace windows if the following conditions occur:
• Foggy Windows
• Structural Problems
• Major Water Leakage