faqs
Comparing replacement vs. new construction windows: Key differences & how to choose
Aug 8, 2024|Updated Oct 14, 2026
Replacement windows are designed to fit into an existing window frame, making them ideal for remodels and upgrades. New construction windows include a nailing flange and are installed during new builds or major renovations where the wall is open. The right choice depends on your project scope, budget, and the condition of your existing window frames.
Replacement windows and windows made for new home construction have a slight difference. Infinity can help you understand both types of windows. Here’s what you need to know about replacement vs. new construction windows.
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What are new construction windows?
New construction windows are windows designed for new home construction or remodeling projects. New construction windows get installed in places without exterior cladding, like stucco, or trim. They include a window frame and nail fins around the perimeter. They can get used as replacement windows, too. New construction windows installed as replacement windows are referred to as full-frame replacement.
What are replacement windows?
Replacement windows can come with or without nailing fins. A nailing fin is a thin strip attached to the exterior side of a window, used to secure the window during installation. When they have nailing fins, it's called full-frame replacement. Full-frame replacement will also include a frame for the window. Replacement windows without a nailing fin are called insert replacement windows when installed. Others refer to them as pocket windows. They get installed into an existing window frame.
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Insert replacement
If your current frames are in good condition and you want to maintain current window size and style, this may be the right option. The new windows are inserted directly into your existing frame for more efficient, less disruptive installation, which can minimize labor costs.
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Full-frame replacement
This approach is used if you want to completely transform your home with a new style or larger window. Your consultant may also recommend this method if water or structural damage are a concern. While full-frame replacement has less impact on your exteriors than a new build, it does require removal and replacement of trim.
What’s the difference between new construction windows vs. replacement windows?
The difference between replacement windows vs new construction windows is their parts. New construction windows include a window frame and nail fins. Some replacement windows can have frames and nail fins, but most don't have nail fins. They get "inserted" into an existing frame when installed. Siding and trim get removed before full-frame window replacement installation. The siding and trim get reapplied after installing the window.
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New construction windows vs. replacement windows installation
The installation method for new construction windows is full-frame window installation. Installing replacement windows without nail fins is insert window replacement. Full-frame window replacement removes the existing window frame to install a new frame and window. Insert window replacement installs the window into the existing window frame. Infinity partners do both kinds of window installation.
The type of installation method used depends on the condition of the window frame. A deteriorating window frame can need replacement. If the window frame has damage, it can mean air leaks, which can decrease the energy efficiency of your home. Around 30% of a home’s energy loss takes place through windows, according to the U.S. Department of Energy (DOE). So, it’s important to have energy efficient windows and window frames in good condition.
If a window frame is beyond repair, then full-frame windows are the best option. The full-frame installation will resolve any issues you had with the old frame.
Installing new construction windows can take more time than installing insert replacement windows. Full-frame installation means removing any siding, trim, and the existing window frame.
Window design options
New construction windows and replacement windows offer window style options. You have the flexibility to create a custom window with each type. Infinity custom builds all windows, allowing you to create the look you want for your home. You can add custom-built Infinity windows as part of a remodel. We also custom build insert replacement windows to ensure a proper fit for your home. Insert replacement windows can have fewer design options, since you're limited to using existing frames in your home.
New construction windows vs. replacement windows: Energy efficiency
Both new construction and replacement windows are energy efficient replacement windows. Infinity Ultrex® fiberglass windows have less thermal conductivity than rolled-form aluminum. That means they help your home stay comfortable all year long by keeping the heat and cold out.
The installation method can impact your home’s energy efficiency. The nail fins of new construction windows attach to the studs of a wall for a proper fit. Insert replacement windows rely on the existing window frame. The condition of the frame can impact your home’s energy efficiency. An existing window frame can experience air leakage, depending on its condition. Air leakage can decrease your home’s energy efficiency.
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Where to use new construction windows
New construction windows get installed as part of home additions. They also get installed where new windows are getting added in spots they didn’t exist. It can mean creating a new opening in a home. In other spots, new construction windows can get used where a frame has aged past repair. New construction windows need an opening that's down to the studs to secure the nail fin. A home's siding and trim needs removal to install new construction windows.
Where to use replacement windows
Replacement windows and their installation methods means more flexibility. Full-frame replacement windows fit best when existing windows need a new frame. Insert replacement windows can go where you already have windows, and the frame's in good condition. Insert replacement windows work great if you like the window style you have and need an upgrade.
Replacement vs. new construction windows pros and cons
Replacement windows and new construction windows have their advantages and disadvantages. The type of window installation depends on your project.
Performance
Replacing your windows can improve your home’s energy efficiency. Newer windows have energy efficient features like Low-E glass coatings. They reflect solar heat out or help a home keep heat in cooler months. Full-frame window replacement offers the advantage of replacing the frame. Replacing the frame can seal up spots where air can leak. New construction window installation allows inspection and repair of any water damage.
Window replacement process
The window replacement process differs between new construction windows vs. replacement windows. Full-frame window installation requires a few more steps. It also offers the opportunity to improve your home’s energy efficiency. Replacing flashing during installation helps prevent moisture issues. The new sealant can help stop cold air from entering your home in winter and escaping your house in summer.
New construction window installation can take longer to complete than insert window replacement. It requires removing siding and trim. It can also take more material. A full-frame replacement window installation can take several hours. The installation time depends on trim removal, plus any siding removal and replacement. It can take a two-person crew about an hour to replace an insert window.
Frequently asked questions
Whether it’s better to use replacement windows or new construction windows depends on your project. If you’re replacing a window with a broken seal, an insert replacement window might be the best option. If you want to remodel your home and windows, new construction windows offer more options.
It’s possible to use replacement windows in new construction if there’s a window frame in place. You can also use full-frame replacement windows in new construction. You can use them because they include a frame and nail fins.
Retrofit windows are another name for replacement windows. They are new windows that fit an existing window frame. Retrofit window installation is the same as insert window installation.