It is critical to understand the types of windows and installation process for replacing your windows: (1) Replacement pocket windows, (2) Replacement full-frame windows, and (3) New construction windows

window replacement

Replacement windows are defined as windows installed into a pre-existing window opening or existing frame, while new construction windows are designed for homes that have yet to be constructed or used in the instances where the siding can be removed (down to the studs of the walls) before it can be replaced.

Key differences. pros, and cons between replacement and new construction windows


Replacement windows are designed so that the installer does not have to remove any exterior materials of a home including the siding and exterior cladding. The most popular replacement windows are pocket windows installed into a pre-existing window frame.

Pros: This enables the windows to be installed from the inside of the home without damaging the wall, window trim, or siding, which saves time and money because the installation is quicker and less invasive, as the only part of the home that will be touched is the window itself.

Cons: However, it is not an ideal replacement option if you are having any water intrusion from the exterior due to improper window flashing. The pocket window does not address the actual window frames or flashing issues. In addition, it causes glass loss, in other words, the new window will have less glass area than the original window. This is because the new window is being placed in the pocket frame of the old window and not the actual frame. Finally, it will be less energy efficient if the actual window opening is not properly insulated.


The best option for the replacing window is the full-frame replacement. New construction windows are designed to be installed into a brand-new home, an addition to a home, when the studs are exposed, or having a water intrusion from the wall. The new construction window has a component called a nail fin or flange frame, which means the windows will be nailed directly onto the frame.

Pros: The new construction window is more water and airtight than the replacement window. It will completely protect the window opening with the up-to-date building codes. It will also provide the original glass size (the maximum glass size). Finally, the opening can be completely insulated to significantly increase your home’s energy efficiency. Most of the energy wastage is resulted due to the poor insulation around the windows.

Cons: As a replacement window option, it does require the removal of attached siding/cladding. It will be invasive and requires additional interior work. The cost of installation will be higher than the standard replacement windows.