Tips

New construction vs. replacement windows: Which is right for your project?

If you’re wondering whether to choose new construction or replacement windows, the correct choice will depend on your project. Find out how to start making this determination, so you can move forward confidently.

If you’re building a new construction home, the answer to which window is best is simple: a flanged full-frame window (commonly called a “new construction” window). If you’re replacing or remodeling your home, there’s more to consider, because either a new construction window or a replacement-specific window (full-frame or insert) could work. We’ll walk you through the considerations as you’re evaluating new construction versus replacement windows, so you can make the choice that best suits your project.

What are the three main types of window installations?

There are three different ways that windows can be installed. We’ll explain why you might choose a flanged full-frame window, flangeless full-frame window, or an insert replacement window.

1. A flanged full-frame window is ideal for new construction and major remodels

In a new construction build or major remodel where new walls are being built, a flanged full-frame window is ideal This window is made for installing before siding and trim due to its nailing fin, which we refer to as a nailing flange or installation flange. This vinyl lip runs around the perimeter of the window frame and comes with predrilled holes for installation.

2. A flangeless full-frame window is ideal for replacement projects where the opening will remain the same

In a smaller remodel or a window in/window out replacement project, a flangeless full-frame replacement is one good option. The reason it works well for an existing opening is that it doesn’t have a nailing fin, like a flanged full-frame window does. This means its installation won't require peeling back siding and removing trim. A flangeless full-frame window does come with a new frame around it, so the old window and old frame will be removed, and the new window will be installed inside the existing opening. This is a less invasive option than installing a flangeless full-frame window (“new construction”) as it will also allow you to preserve your trim and siding.

3. An insert replacement window is a simple solution for window in/window out projects

In a project where you are just removing old windows and installing new ones, and no other home improvements are included, an insert replacement window can be ideal. It has neither a nailing fin nor a new frame. It’s installed by removing the old sash (glass and framing around it) and reusing the existing window frame. This makes it the least disruptive replacement option and, like a flangeless full-frame, allows you to keep siding and trim. It’s important to know that an insert replacement window can only be used when your existing frame is in good condition, and there are no issues with leaking air or water.

Psst ... If an insert won’t work for your window in/window out project, a full-frame flangeless window is another option that comes with a less disruptive installation.

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Which window type does your project need? A quick guide

Get a quick answer to which option is best in a couple of the most common replacement scenarios.

Windows for a new construction home

When you are building a new home, you’ll want a flanged full-frame window. The flange (or nailing fin) makes the window quick to install and also makes it easier to install in a way that seals against the elements.

Windows for an addition or major remodel

When you’re undertaking an addition that involves building new walls, you will, again, want to choose a flanged full-frame window. It’s the quickest to install and makes it easy to connect control layers. This is how the pros describe the steps taken to manage water, air, vapor and thermal energy, or more simply put, protect the house from the elements.

Windows for remodeling or replacing siding

When you are remodeling or replacing siding, you once again have the option to replace with a flanged full-frame window, which is installed before siding and trim. The nailing fin makes this window easier to install and easier to connect with the drainage plane, which is the part of the wall that encourages water to drain away, rather than into, the home.

Windows for when your frames are in good shape, but the glass is damaged or outdated

When your window frames are in good shape but the glass is damaged or outdated, you could choose an insert replacement window. The frame must be in good condition for this type of installation. In addition, you'll want to be confident there are no issues with leaking water or air because you’re relying on existing systems to keep these elements out of the home.

Windows for when frames are rotted, warped, or no longer square

When your window frames are rotted, warped, or no longer square, you will likely pick a full-frame replacement window. This will allow you to replace the problematic frame without disturbing your siding or trim. However, you could select a flanged full-frame window too. The second option will work if you are able to peel back the siding or trim and are willing to take on a project with a larger scope and more expensive window units.

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New construction vs. Replacement windows: A detailed comparison

Window installation considerations

A flanged full-frame window has a nailing fin (or flange) that means it must be installed before the siding. This is easily done in a new construction project. In a replacement project, it can be done where it’s possible to peel back the siding or alternatively, where a buck can be built. A buck is a structurally sound frame that is built inside the rough opening, which is the hole in the wall where a window or door is installed.

A full-frame replacement window is one that fits inside an existing rough opening, after the old window and frame have been removed. This type of window doesn’t require removing siding or trim, so it’s less invasive than the installation of a flanged full-frame window.

An insert replacement window fits inside an existing window frame, so it’s the least disruptive window replacement option. Siding, trim, and the existing frame all remain. None of the finishing details that can add time, labor, and costs will be needed here.

Window replacement cost comparison

Flanged full-frame and flangeless full-frame windows will be more expensive than insert replacement windows. This is because insert replacement windows are the simplest window units from the perspective of materials and manufacturing. Keep in mind the window unit is only one aspect of pricing; the installation costs associated with flanged full-frame windows will be higher because of the finishing required to replace trim and siding.

Window energy efficiency

A flanged full-frame window is easiest to install in a way that ensures it performs as efficiently as intended. This is because of the nailing fin, which makes it easy to flash. This is how the window is connected with the control layers. Remember, this is how pros describe the systems put in place to keep outside elements out and inside air in.

This doesn’t mean the other options don’t offer energy efficiency. A full-frame replacement window is sealed on the exterior side when it's installed, and an insert replacement window relies on the existing systems for managing the elements.

If you have concerns about your existing windows leaking air, you will want to opt for a full-frame replacement window or a flanged full-frame window, as both options will give you the opportunity to install in a way that will improve energy efficiency, rather than relying on existing systems.

Aesthetic impact of windows

There are several different ways to think about the aesthetic impact of choosing one of these window options over another. Here are some questions to ask yourself:

Are you replacing all your windows or only a few? If you are only replacing a few windows and don’t have firm plans to replace all windows, you might be best off using a replacement option that will allow you to keep your existing trim, so a full-frame or insert window.
Do you have special trim in your home? If you live in a home with beautiful, traditional wood trim, you understandably might not want to lose this aspect of your home’s character. Either a full-frame or insert window will allow for the trim to be preserved.
Do you want the most daylight possible? If so, you should be aware that insert replacement windows, by fitting inside the existing frame, will cut down somewhat on the amount of daylight inside your home.

The best way to decide on the right replacement option for your home will be to speak with a contractor who is experienced in window and door replacement. We can help you find a pro in your area who specializes in our products.

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Frequently asked questions

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Tips

New construction vs. replacement windows: Which is right for your project?

What are the three main types of window installations?

1. A flanged full-frame window is ideal for new construction and major remodels

2. A flangeless full-frame window is ideal for replacement projects where the opening will remain the same

3. An insert replacement window is a simple solution for window in/window out projects

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Which window type does your project need? A quick guide

Windows for a new construction home

Windows for an addition or major remodel

Windows for remodeling or replacing siding

Windows for when your frames are in good shape, but the glass is damaged or outdated

Windows for when frames are rotted, warped, or no longer square

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New construction vs. Replacement windows: A detailed comparison

Window installation considerations

Window replacement cost comparison

Window energy efficiency

Aesthetic impact of windows

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Frequently asked questions

Can I use new construction windows for a replacement project?

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Do replacement windows have nailing fins?

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When is a full-frame replacement necessary?

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Why are new construction windows sometimes cheaper?

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How do I measure for replacement vs. new construction windows?

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Ready to get started with your project?

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Design Tool

Product Discovery

Questions? We’re here to help.

Understanding Andersen vs RbA

Product guides

Window & door install

3. An insert replacement window is a simple solution for window in/window out projects

Which window type does your project need? A quick guide

Windows for a new construction home

Windows for an addition or major remodel

Windows for remodeling or replacing siding

Windows for when your frames are in good shape, but the glass is damaged or outdated

Windows for when frames are rotted, warped, or no longer square

New construction vs. Replacement windows: A detailed comparison

Window installation considerations

Window replacement cost comparison

Window energy efficiency

Aesthetic impact of windows

Do replacement windows have nailing fins?

When is a full-frame replacement necessary?

Why are new construction windows sometimes cheaper?

How do I measure for replacement vs. new construction windows?

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