New construction windows vs replacement windows - what’s the difference? Homeowners ask us this frequently.

So, what is the difference?

To put it simply, replacement windows are installed into an existing window opening without disrupting the wall, trim or frame significantly. New construction windows are installed by exposing the framing of the wall and is a far more intrusive process. This could be during the actual new construction of a house or an addition or when a new window opening is being cut into an existing wall, or just at the discretion of a homeowner. We say discretion because in most cases it’s not necessary and the extra cost usually can’t be justified. Going the new construction route is more intrusive and therefore more costly. 


So let’s go into more detail on both window installation options. 



The physical difference

One important physical difference is how the two types of windows are attached to the home. New construction windows have something called a nailing fin -- a small extension with nail holes in it that runs around the entire edge of the window. The nailing fin is placed flush against the sheathing of the house, which is more commonly known as plywood, and gets attached from the outside so it requires that the siding and/or trim be adjusted and then re-installed appropriately to fit the new window. This is one of the reasons new construction windows have a higher installation cost than replacement windows.

Replacement windows do not have a nailing fin because they are inserted into an existing window frame and then attached through the inside of the frame. Replacement windows are custom-measured and sized to fit each window opening perfectly and, in most instances, are installed from the inside of your home without needing to cut back the interior wall. In most situations, installing a replacement window is done by removing the interior stop, siliconing the frame perimeter, setting the new window, insulating using low-expansion foam around it to ensure no air or water infiltration, and then appending the interior stop to secure the unit. 



When to choose replacement windows

Replacement windows are going to be your best option when your existing frame can accommodate it as determined by an expert contractor like ours. You can schedule a time for our expert to provide an in-depth in-home consultation here. Because replacement windows are installed into the existing window frame, the installation process is easier and faster in most cases while not compromising on the aesthetics of your home or on energy efficiency.

In fact, most of our homeowners choose replacement windows for their ease of installation, durability and to enhance the beauty of their home. Renoviso’s selection of replacement windows includes vinyl, wood, and composite options that are fully customizable across a range of colors, grid designs and styles, even those with older homes.


When to choose new construction windows

There’s a common misconception that new construction windows are more “weather-tight” or somehow higher quality. But in most cases, these are inaccurate. Replacement windows are the appropriate solution in most situations but there are scenarios where new construction windows are the better option and the cost can either be justified or can’t be avoided. Consider new construction windows if you are:


1) Building a new home or an addition on your existing home

2) Adding a new opening and window where one did not exist

3) Where the window frame itself needs repair that goes beyond the frame itself and into the framing of the house, which should be determined by one of our professionals. 


Need advice? Start by talking with a Project Consultant 888-867-1660.

Many of the replacement windows we install are also available as new construction windows -- with an additional cost per window that we provide in the quote. These windows provide the same level or slightly better energy efficiency, and the same durability and style as their replacement counterparts. 



Will I lose glass space?

Homeowners frequently ask us if they will lose glass space with a replacement window. There is a very small amount of loss because the jamb of the replacement windows sits flush between the window frame and the house frame but new construction windows have a slight overlap between the window jamb and the window frame.

The result is usually no more than a half-inch of glass space lost on each side of the window. For most homeowners, this small loss in glass space is insignificant and not worth the additional cost and effort of opening up the wall to install a new construction window.

Still unsure which is right for you?

Call or email us and we’ll be happy to help:  888-867-1660 or