There are two types of replacement windows that are installed in the buildings: new construction and retrofit.

A new construction window is designed to be installed in the brand new home, or in the building during the construction phase. These windows are typically installed before the exterior siding or brickwork is done, and are fastened directly to the framing of the house. New construction windows are also installed in the existing buildings when an old frame is leaking, or if client wants to take advantage of full opening. A new construction window is bigger than a retrofit by about 2-3” on width and 2-3” on height. This method is less popular due to additional labor price, because installer has to replace a trim and / or stucco, that may add $200-600+ to the labor cost per window.

Also, if the opening of the bedroom window is more than 44 inches above the floor, the code does not allow this height to be “grandfathered in” anymore. It would need to be brought up to current code requirements. This means the window opening will need to be lowered, which would involve cutting, drywall work or a new casing. This would add approximately $400 or more to the cost of each window that requires this work.

Another problem that may arise with new construction windows is lead contamination. Federal law requires contractors that disturb painted surfaces in homes built before 1978 to be certified and follow specific work practices (RRP). And this entails additional costs.

A retrofit window, on the other hand, is designed to be installed into the existing frame. This type of replacement is often used to update the appearance of an older home, to increase energy efficiency, or to improve the functionality of the windows. Retrofit is installed as a replacement in the existing window frame without removing the original frame, thereby without disturbing the interior or exterior finishes of the home. There is also no issue with lead contamination. This method is cheaper, because installer doesn’t have to open the walls. However it comes with a smaller opening, because an original frame has to stay in the wall, and it is just covered by vinyl “flatrim” or casing.

In summary, the main difference between new construction and retrofit windows is the installation process and the installation price. Both types are leak proof and will last the same amount of time if properly installed.