Energy Efficiency Showdown: Replacement vs. New Construction Windows

December 19, 2023

Last updated on February 2, 2024

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Home renovations are stressful for everyone, especially when you are unsure what window improvements are best for your project. So, you want to know what is the difference between new construction windows and replacement windows.

The good news is that both windows are energy efficient to varying degrees. The significant differences between them are cost, installation, and labor. 

Kryger Glass offers a variety of residential glasses as well as glass window replacement services to get you started in your renovation journey. Installing glass doesn’t have to be expensive or complicated, and with Kryger Glass, it isn’t.  

Continue reading to discover why new construction windows and replacement windows are so different. 

New Construction Windows vs. Replacement Windows

Understanding when to use each type of window is crucial. New construction windows are essential for significant renovation projects. For example, you must use a new construction window when demolishing and rebuilding a wall. This necessity arises because no existing frame accommodates a replacement window.

What Are Retrofit Windows?

Retrofit windows, commonly known as replacement windows, fit into existing frames. The term ‘retrofit’ implies adding to or modifying something. In this context, it means installing new windows into pre-existing frames.

Cost Considerations

New construction windows typically cost more than retrofit windows. This price difference is due to the extensive labor required for new construction windows and their customizable nature.

Are Replacement Windows More Affordable Than New Construction Windows?

Yes, replacement windows usually cost less than new construction windows. This is because they don’t require an entire construction team for installation and are often available in standard sizes.


When it comes to labor, replacement windows require the least amount of effort. That’s not to say that they do not need professional installation – they do, but the completion can take less than an hour. That’s the total labor time the homeowner spent calling a professional and the time it took the professional to fix the issue. 

New construction windows are often part of a much larger project and can go weeks or months without completion. 


Installers secure new construction windows with nail flanges using screws during the wall construction process. These flanges, running along the window’s perimeter, integrate the frame as part of the window. This method, being more invasive, differs significantly from installing replacement windows.

Replacement windows come with smooth sides to ensure easy insertion. When installed properly, they form a watertight seal. Measuring the existing window space before purchasing a replacement window is essential. Due to their design for fitting into existing frames, replacement windows typically lack customization options.

Can you use new construction windows as replacement windows?

There are rare instances where cross-over between the window types makes sense. One is if you find yourself replacing a window and part of the wall supporting the frame is damaged. In that case, it’s better to use a new replacement window instead, which means removing the frame.

Replacement Windows vs New Construction: Energy Efficient?

Energy efficiency is the term used to measure whether a space will save you money in the long run through energy-preserving means. Glass windows for homes play a significant role in keeping heating and AC bills low by keeping all that precious air inside the house. Let’s look at which window will likely save you the most money on energy. 

Replacement Windows

  • These windows must snugly fit the size and shape of the existing frame.
  • They depend on the integrity of the current window frame for stability and security.
  • A damaged frame or an inadequate fit can compromise efficiency. It’s crucial to assess the condition of the existing frame before installation.

New Construction

  • Installed using screws and nail flanges. 
  • More secure than replacement windows. 
  • Tight seal and insulation.  

When comparing replacement windows vs. new construction windows, new construction often takes the lead in terms of security and insulation. However, replacement windows still meet industry standards for energy efficiency. The choice largely depends on the condition of the existing frame they will replace. Generally, both windows maintain a comfortable indoor temperature, retaining heat in the winter and cool air in the summer.

Help is Here

Still not sure which one is right for you? Give Kryger Glass a call today. 

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