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What Causes Window Drafts?


Drafty windows can cause a chill in your home and make your home less energy efficient. It’s important to know the causes of drafty windows and how to fix drafty windows. Learn the common causes of window drafts and some drafty window fixes. 

Why Windows Get Drafty 

Windows become drafty for several reasons. Often drafts start because windows have gotten old. Weather barriers like caulk can crack or peel, too, which impacts the ability to stop drafts. Insulation around the window can settle, reducing effectiveness as a house ages. Windows can also warp over time and experience seal failures. Some of the fixes are easy while others can take more time and expertise.  

Air Leaks 

Windows get drafty when air leaks through openings around the window. The leaks can sneak through caulk cracks, caulk gaps, or gaps behind the trim. Air leaks can start to appear over time as a house settles. You can also find air leaks in different parts of your house, like exterior doors and other openings.

When you have gaps where air leaks through, cold air can get sucked into your home because of the stack effect. The stack effect occurs when hot air rises and escapes through an attic. As that air leaves, it gets replaced by cold outside air and makes your home feel drafty. 

Poor Insulation 

Older homes can suffer from a lack of insulation. Insulation can even fall down or fall out of place, if not properly installed. That leaves the area around your windows exposed for air to pass through. To inspect the insultation, you’ll have to remove interior trim. Any kind of loose insulation may need replacing with new insulation to seal out any paths for air to leak.  

Broken Seal 

Windows with multiple panes have a seal between the panes. The seal holds an inert gas in place for energy efficiency. That seal can break and create a path for air to pass through. If condensation appears between the panes, it’s likely the seal has failed. A manufacturer’s warranty often covers seal failures.  

Cracked Window Caulk 

When caulk gets old, it can crack, which leads to gaps that air can enter. Faulty caulk tends to cause most window drafts, but it’s an easy fix. Use a high-quality caulk for re-caulking to seal out leaks. 

Old or Warped Windows 

Old windows can warp over time if exposed to extreme temperatures. Warped windows can become difficult to open and close because they don’t fit in the frame properly or parts have started to fail. Warped and old windows that don’t operate correctly can be a sign to replace your windows

Window Aren’t Energy Efficient 

Some window materials have better energy efficiency or thermal conductivity than others. Our Ultrex® fiberglass windows have 5,000x less thermal conductivity than rolled-form aluminum. That means energy doesn’t transfer as easily through it. Your windows can help your home remain cool in the summer by rejecting solar heat and keep it feeling warm in the winter by limiting heat from leaving through your windows.  

Get a Home Energy Audit to Pinpoint Drafts 

Home energy audits are a good first step to stop drafty windows. They can pinpoint trouble spots and provide suggestions on how to improve your home’s energy efficiency. A home energy audit inspects each room in the house. Professional energy assessors use infrared cameras, furnace efficiency meters, and surface thermometers. They also do a blower test, which measures how much air is entering or escaping your home. 

How to Fix Drafty Windows 

Fixing drafty windows can mean: fixing locks, adding weatherstripping, window treatments, sealing windows, caulking gaps, insulating windows, or using a draft stopper. You can fix drafty windows in a few steps usually. But some issues might mean you need replacement windows.  

  • Broken locks can mean a window doesn’t close properly, leaving a space for air to enter. Windows need to form a seal when closed to prevent drafts.  

  • Weatherstripping ages and breaks down over time. Replacing old weatherstripping can help prevent drafts from entering your home. 

  • Window treatments can help prevent drafts by creating a barrier for the cold air. A draft stopper works in a similar way when placed on a window sill. 

  • Sealing windows and caulking gaps can eliminate spots where drafts can enter.  

  • Insulating windows can help get rid of drafts. People often use shrink wrap film to cover their windows in winter.  

Replace Drafty Windows 

When your drafty windows become unbearable, the best solution is window replacement. You can recoup between 61% and 68.5% of the replacement project cost when you sell your home, according to Remodeling Magazine’s Cost vs. Value report

Benefits of Fixing Drafty Windows 

There are several benefits to fixing drafty windows. The most obvious benefit is eliminating the draft. There are also potential financial benefits to fixing drafty windows. Benefits include: 

  • Save money: Energy efficiency matters. The average American household spends $1,500 to $2,500 a year on energy bills. About 45% of those costs go toward heating and cooling costs. It’s important to find ways to reduce energy loss with windows because it can improve your home’s energy efficiency. If you have single pane windows, you can save between $101 to $583 each year by replacing them with ENERGY STAR® windows, according to the U.S. Department of Energy

  • Increased energy efficiency: If fixing your drafty windows means updating your insulation, you can see benefits. The improved R-value of new insulation can improve your home’s energy efficiency. The insulation around your windows can deteriorate or droop over time, making it feel like you have drafty windows.  

  • Feel more comfortable in your home: If you replace your old windows with new Marvin Replacement windows, you can choose one of four glass coating options. The coatings can reflect solar heat out if you live in a hot climate. They can also help keep solar heat in if you live in a colder climate. You can feel more comfortable with the temperature inside your home, especially if you live in areas like Philadelphia or Boston where you can experience cold winters and hot summers. 

  • Protect your home from UV rays: Depending on the glass option selected, our glass coatings can block out 84 to 95% of UV rays. UV rays can fade the colors on décor items in your home. 

  • Extend window life: When you seal your windows with caulk or sealant from water and air, you can extend the life of the window. Left unchecked, leaks can begin to break down a window and start to warp it. It’s important to check caulk and sealant around your windows to make sure it’s in good condition. 

Ready to Stop Window Drafts for Good? 

Schedule a free, no obligation design consultation with Marvin Replacement today! See how we can bring better living to your home with stylish and durable fiberglass windows. 


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