Can You Replace Windows Without Replacing The Frame?


When the time comes to replace your windows, you’ll have many options to consider. In addition to aesthetics, shape, size, and how the window functions, you’ll also have to decide where you want to go for a full-frame replacement or just install a window in an existing frame. Read on to discover whether replacing a window without having to replace the frame is an option you can consider.

Can you replace windows without replacing the frame?  If your home has window frames that are in good shape and you intend to insert a replacement window of the same shape, size, and operating style, you can opt to install a new window within an existing frame.

This is known as a pocket frame window replacement or an insert window. This allows you to upgrade your window without having to replace the trim and siding. It’s an easy and cost-effective way to update your windows. However, insert windows may not be an option if you have very poorly insulated windows or rot is present in the window frame, casing, trim, or sill. In these cases, you should consider going for full-frame replacement windows.

Your window replacement project will depend on a variety of factors. A good place to start is to find out whether you need a full-frame insert replacement or if you can get away with an insert replacement window. This post looks at the construction of windows as well as the difference between insert and full-frame replacement windows.

What are the main parts of a window?

An operable window is made up of the following primary elements:

  • Mainframe

This is the outermost part of a window. Sometimes referred to as the jamb or window reveal, the main frame holds the main working parts of the window together within the wall opening.

  • Jamb liner

Historically, windows used weights or pulleys to support the sash. Today, jamb liners are placed on two opposite sides of the mainframe. On horizontally or vertically sliding windows, the jamb liners serve as tracks or runners for the sashes to slide on.

  • Sashes

These are parts of the window that hold the glass. You may have one or two sashes depending on the window style.

What are full-frame replacement windows?

To install a full-frame replacement window, you need to completely remove an existing window down to the studs. 

This means you have to remove every part of the window, including the mainframe, exterior and interior trim – and sometimes siding – for the new window to be installed in the opening. 

When should you choose full-frame replacement windows?

  • There is rot in the window frame, trim, sill, or casing
  • You’re remodeling your home and want to change the shape or size of your window
  • Your existing window is made of aluminum, vinyl, or fiberglass

Benefits of full-frame replacement 

  • By exposing the original window opening, full frame replacement allows for removal of areas with rotting wood if present.
  • It allows for inspection of the window opening for signs of water damage.
  • With precise sash-to-frame fit, full-frame replacement increases energy efficiency.
  • Unless you intend to change the original style of your window, you shouldn’t lose any glass
  • Full-frame replacement allows you to add insulation around the perimeter of the rough opening if need be.
  • If your replacement window is a cladded wood style, the exterior becomes low maintenance.

Downsides of full-frame replacement windows

  • This type of installation carries a higher price point
  • The removal and replacement process is extensive and time-consuming

The removal process

  • The lower sash is removed
  • The upper sash is removed
  • Trim and casing are removed
  • Sill and mainframe are removed

This is an extensive project that is best left to a professional window installer or a competent DIYer. If the installation is carried out properly, investing in full frame window can yield major returns – proper installation can help you significantly reduce your energy spending as well as increase the aesthetic (and overall) value of your property.

A full-frame replacement window provides significant energy savings because each window is installed as a single unit. Because each element of the window is built at the same time to work together, the sashes will fit precisely within the main frame. As a result, air leakage is minimized.

Additionally, if your installer does custom sizing, the mainframe of the replacement window should leave about a quarter inch of room around the perimeter. That bit of space allows your installer to properly insulate and shim the replacement window within the existing opening. 

To reduce the cost of the extensive removal and installation process for full-frame windows, consider keeping the project simple by having your installer put in windows of the same size as the original openings. 

Needless to say, if you want to transform your home, going for full-frame replacement offers the flexibility to choose a new style or size window. For example, you can replace a hard-to-reach double hung window with a more convenient awning window. If the budget allows, you can add a door where there was once a window by increasing the size of the opening, or you can even bring the window sill closer to the floor to extend your view and let more natural light into a room.

What are insert windows?

With an insert window replacement, a new window is installed within the existing window frame. Sometimes known as a pocket window or a frame-in-frame replacement, this type of window replacement becomes an option when your existing aluminum or wood window frames are structurally sound and you want the existing interior and exterior trim to remain intact.

Before installing the window, the existing sash and jamb liner liners are removed and the new window is inserted into the existing frame where it is anchored, insulated and sealed. As a result, the overall glass unit surface of your newly installed window unit will be smaller than the original.

When are insert replacement windows an option?

  • There is no water damage or rot present in the window frame
  • The window frame is in good condition
  • You want a replacement window that is of the same shape, size, and operating style

Benefits of insert replacement windows

  • These are typically less expensive than full-frame replacements
  • Installation is less extensive and time-consuming
  • In addition to the original frame, you also get to preserve the existing interior and exterior trim

Downside of insert replacement windows

  • These are only an option if you have structurally sound aluminum or wood frames
  • You may notice a slight reduction in glass surface
  • Leaving the original frame in means that it will eventually need to be replaced anyway.

The removal process

  • The lower sash is removed
  • The upper sash is removed
  • The jamb liners are removed

Whether or not installing insert replacement windows is an option entirely depends on the material and condition of the existing window frame. If you want to preserve your wood windows, these replacement windows are a suitable option because they’re typically more affordable than their full-frame counterparts. Insert windows are also a great option if you want to keep the project small and affordable.

Other factors to keep in mind

As you try to make up your mind on the type of replacement window to go with, you’ll also want to consider the scope of your window replacement project. Here are a couple of things you’ll need to figure out:

  • Are you satisfied with the current operating style of the window you plan to replace?
  • How many windows do you need to replace?
  • What kind of material is the existing window frame made of?
  • If the frame is made of wood, is it in good working condition?

If you feel like a full-frame replacement is the best option for you, here some things you should ask yourself:

  • Are you willing to fork over more money to buy a full-framed window and have it installed?
  • Do you intend to replace your existing windows with the same materials, or are there other options that can improve your home’s efficiency?
  • If your budget doesn’t allow it and your wood window frames turn out to be in god condition, would you consider choosing to install insert glass windows despite their reduced glass surface to save money?

If you come to the conclusion that insert replacement windows are more suitable for you, ask yourself:

  • Do you mind potentially losing some glasses to save some money on your replacement windows?
  • Do you plan to replace all the windows along the wall of your home, or just one? Keep in mind that a newly framed window is going to be inserted within the existing frame, so this could look odd.
  • Is there any chance that your existing window frame may be damaged by water? Mold and rot can spread to the newly installed window unit and cause bigger problems; this could make an insert replacement window the more expensive venture.

Final thoughts

Being informed on the different window replacement options will help you make a more suitable purchase for your home. It’s important to do your research, starting with this post to help you narrow down your options and finding exactly what’s best for you.

Melanie Asiba

Melanie is an author. She enjoys traveling, reading and trying out new things. In addition to writing for Apartment ABC. Connect with her at [email protected]

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