Checking that your home’s windows provide good insulation against outside temperatures is critical to comfort and energy efficiency. But how do you know when to replace old, drafty windows? 

There are a few telltale signs that your existing insulated windows have deteriorated and need an upgrade. This guide covers the signs of inefficient windows, how to test their insulation, top energy-efficient replacement features, and whether to opt for DIY or professional installation. 

Evaluating Window Efficiency

Before deciding whether to replace your windows, it’s essential to thoroughly evaluate their current energy efficiency. There are several DIY tests and professional assessment options to determine if your existing windows are up to par or need an upgrade.

Follow these steps to evaluate your windows’ insulation performance and if your windows need to be replaced:

  • Inspect the glass panes closely for condensation or fogging. This is a sign of failed seals.
  • Check for gaps or cracks in the weatherstripping, as damaged or missing stripping causes air leakage.
  • On a cold day, feel near the windows for drafts, which signal poor insulation. 
  • During daylight, look for light coming through gaps in the frames, which indicates air leaks.
  • Have an energy auditor do an insulation test with a thermal imaging camera. They can pinpoint issues quickly and provide you with the best solutions. 
  • Try taping clear plastic over the windows on a cold night. Compare indoor condensation to uncovered windows. More condensation indicates poor insulation.

Energy-Efficient Replacement Benefits

Upgrading to energy-efficient windows offers many benefits:

  • Advanced Low-E coatings optimized for your climate keep heat in during winter and out during summer.
  • Inert gas fills, like argon or krypton, between panes reduce heat transfer better than regular air.
  • According to ENERGY STAR, composite window frame materials like fiberglass and vinyl are better insulators than metal frames.
  • Tight weatherstripping prevents air infiltration around the frame.

I recommend looking for climate-specific windows for maximum efficiency in your region. Also, consider windows with an ENERGY STAR climate rating tailored to your home for the best energy efficiency options. 

DIY vs Professional Window Replacement

Homeowners with renovation experience can DIY window replacement to save on labor costs. However, consider hiring a professional installer for complex jobs or if you lack experience. 

A window professional has the skills to properly remove old windows and install new ones without damaging the framing or exterior. Also, you won’t have to worry about purchasing specialized tools like laser levels, shims, and framing nails for a straight, secure installation.

Another considerable benefit of professional window installation is labor warranties. Many professionals provide a warranty on installation and materials that protect against defects or water leaks. They can even recommend the optimal types of windows and custom options like tints or blinds for your home and climate.

Lastly, a window technician handles the old window removal and disposal, which can be challenging for DIYers.

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So, Is It Time to Replace Your Insulated Windows?

Replacing worn-out, drafty windows with modern energy-efficient models is one of the best ways to improve home comfort while reducing energy costs. If your windows are over 20 years old, it is likely time to upgrade. Even if the seals aren’t broken, new Low-E coated windows with improved frames offer substantially better insulation, saving you money in energy costs. 

Consider having an energy audit done to evaluate your existing windows’ efficiency. If new windows are recommended, hire a qualified installation company to provide proper installation to avoid air leaks. The upfront investment will pay off through lower heating and cooling bills.

FAQs About Replacing Insulated Windows

How much does it cost to replace insulated windows?

The average cost to replace insulated windows is $600—$1,000 per window. High-end custom windows with extra features can be over $2,000 apiece.

Should I replace just the glass or the entire window frame?

It’s usually better to replace the entire window for optimal energy efficiency and ease of installation. New window frames also provide much better insulation.

How long do replacement windows last?

With proper installation and maintenance, high-quality insulated replacement windows can last 30 years or longer.

When should insulated windows be replaced?

It’s a good idea to replace windows that are over 20 years old. Newer windows provide better insulation, lower energy bills, and improve home comfort. Signs like condensation, fogging, air leaks, and drafts indicate that you should replace your windows.

Do replacement windows pay for themselves?

Energy-efficient replacement windows can pay for themselves in 10–20 years through energy savings, depending on how inefficient your current windows are. Upgrades almost always increase home value by more than their cost as well.

Editorial Contributors
avatar for Amy DeYoung

Amy DeYoung


Amy DeYoung has a passion for educating and motivating homeowners to improve their lives through home improvement projects and preventative measures. She is a content writer and editor specializing in pest control, moving, window, and lawn/gardening content for Today’s Homeowner. Amy utilizes her own experience within the pest control and real estate industry to educate readers. She studied business, communications, and writing at Arizona State University.

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Casey Daniel

Casey Daniel is a writer and editor with a passion for empowering readers to improve their homes and their lives. She has written and reviewed content across multiple topics, including home improvement, lawn and garden care, sustainability, and health and wellness. When she’s not reviewing articles, Casey is usually playing board games, repainting her bathroom, or quilting.

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