New construction windows provide access to the open space in wall studs around window openings, making it easier to add insulation to improve the energy efficiency of the windows. New construction windows also offer the ability to replace wooden sills which may have deteriorated. If you have any issues with the wood moldings surrounding your existing windows then new construction windows are the way to go. With this option you could also make your windows larger if wanted.
Since replacement windows utilize the wooden sills from prior windows, the conditions of the wood will determine the efficiency and longevity of replacement windows. While they do probably provide better insulation value than your existing old windows – there is no way to add any insulation around the window. Replacement windows also offer the benefit of faster installation.
The reason most homeowners put in new windows is for better insulation value. If you are looking for better insulation value, a great window and new woodwork then new construction windows are the way to go.
If your existing woodwork is in great condition and you are happy with your current insulation then a replacement window is an easy way to get new, more efficient windows.
Lenny & Lisa