Did Your Window Seals Fail? 4 Signs to Look Out For


You probably haven’t thought of it, but windows are one of the important parts of the house. Windows allow entry of natural light indoors, give good ventilation, and make a room less confining. To add to that, windows make a home more energy-efficient if it’s is well maintained. With new replacement windows, for example, homeowners can get anywhere from $126 to $465 on energy savings each year (according to ENERGY STAR) when they switch their single-pane windows to newer models.

However, as all things go through wear and tear, even your modern windows can have issues such as a failed window seal. What are the signs of a window seal failure? There are a few clues to help tell if your window seal has failed, like condensation between the glass panes, windows appearing dirty, and warping of window frames – all of these we discuss more in this article.


What does a window seal do?

home20windowDon’t be confused – a window sill is different from a window seal. The latter refers to the seals that modern windows have, which purpose is to contain the air between the multiple panes of glass.

Note that newer windows come with two or three panes that are separated by layers of air or inert gas. These panes are sealed together with an elastic sealant to prevent the gas from escaping. When a window seal fails, moisture and humidity will seep into the areas separating the window panes, causing visibility issues with your windows.

Why do window seals fail?

Here are the most common reasons why window seals deteriorate:

  • Exposure to extreme temperatures – Our home’s roof, walls, doors, and windows all help protect us from the frigid temperatures or boiling hot weather outside. They are our first line of defense when it comes to the harsh weather conditions, which means they take the hardest hit. As window seals act as a protective material to your window panes, they too expand and contract depending on the temperature outside. Prolonged exposure to extreme heat or cold can cause the window seals to shrink, stretch, crack, and become brittle.
  • Harsh elements – While newer windows are built to withstand the harsh elements, strong storms and hurricanes can take a toll on the windows, including the window seals. For example, coastal areas that frequently go through torrential rains can cause strain on windows with the strong winds allowing water to flow through the seals. When this happens, mold build-up, rust, and wood rot can follow and cause issues with the entire window.
  • molds20on20windowMold buildup – As you know, lots of moisture can lead to mold growth and the window seals are not immune to them. Molds weaken the integrity of surfaces and structural parts, including window seals. The best way to prevent this is to remove molds immediately with a cleaning agent designed to specifically eradicate this problem.
  • Age – As you would expect, windows seals will have wear and tear over time. Old windows with old seals need to be evaluated if it’s time for them to be replaced or if there is a way to fix them to preserve the integrity of the windows.
  • Improper Installation – Window seals that are incorrectly fitted will slowly move and will not be as energy-efficient as expected. This underscores the importance of running routine inspections for your windows and seals so that issues will be immediately addressed.

What are the signs of a window seal failure?

Increased snow and dropping temperatures will make you pay attention to your windows – particularly if they are not doing their job helping you keep warm and cozy inside your home. If you’re wondering if you’ll soon need to get a home window replacement, you may want to look at these signs of window seal failure.

  1. When your windows are foggy

    It is common for windows to have condensation every now and then. For example, when you cook or shower, you might notice condensation on the windows because of the difference in temperature indoors and outdoors. This is normal and is not an indication of a window seal failure. What you need to look out for is when there is foggy moisture in between the glass panes.

    A window seal that is working properly will keep the inert gas (which acts as insulation) inside the panes, keeping the windows clear. A sign of a failed window seal is a foggy window that is impossible to clean. Even if you wipe both inside and outside the window, a failed seal will have your windows looking cloudy.

  2. When your windows are drafty

    One of the last things you want to happen in the middle of winter is to have drafty windows, and this is what will happen if you have failed window seals. Having this issue can allow hot (or cold air) to seep through the windows and escape your home while letting in the frigid (or hot) air outside

    One easy way to check if you have drafts around the window is to do the “wet hand test”. Simply dampen your hands with water and hold it up the windowpane. You should not feel any cold air coming from your windows if your seals are still intact.

  3. When the window frames are damaged

    damaged20window20frameAnother easy way to see if you have window seal failure is by looking at your window frames. Do you spot any molds or mildew buildup? Is the paint already chipped or peeling? Are there signs of damage from the sun or the rain? If your frames seem to have sustained damage or are warped, it’s a good sign that your seals have failed and a window replacement is imminent.

  4. When the temperature inside your home is uncomfortable

    Does it seem like you still need to wear your winter clothes inside your home? Is the cold temperature making you uncomfortable? A home that is well ventilated and has proper insulation should not have fluctuating temperatures. If you notice that temperatures shift in your home, it is possible that your windows, including their seals, are no longer working.

What happens when a window seal fails?

Keep in mind that energy-efficient windows will only be effective depending on the usefulness of the seal. With broken window seals, you may just be wasting energy, money, and sacrificing your family’s comfort inside your home.

You’re wasting energy – When you have drafty windows due to broken window seals, you will have an excessive amount of heating and cooling loss. Naturally, your HVAC system or AC will work double-time, which means you’re wasting energy to maintain comfortable temperature levels in your home.

You’re paying higher energy bills -It follows that when your cooling and heating system does its extra work, you’ll be faced with skyrocketing energy bills. And with energy costs consistently rising, you may want to pay attention to how your home can become more energy-efficient.


You sacrifice comfort – When your window seals fail and you don’t address them, you’re not only wasting energy, but you’re also sacrificing comfort. Well-working windows should protect your and your loved ones when you’re in the house, no matter how extreme the weather is outside.


Can the seal on the window be repaired?

home20window20replacementThe straightforward answer to this question is yes, a broken seal on the window could be fixed. This is a more cost-effective solution than having the entire window replaced. However, if you will only have the seals repaired, don’t expect your *once* energy-efficient windows to have the full insulation power that they had. That’s because the inert gas that acts as insulation in between the panes won’t be replaced.

Make sure to check your warranties first before considering a window replacement. See if your window is still covered by warranty, which will save you a lot of hassle and also money.

If, however, your window seal is already damaged beyond repair and your warranty is expired, your best option is to have it replaced. Call a home window replacement service provider to see the best options for your home. Although this is the most expensive option, a new window replacement will increase the energy efficiency of your house and increase your home’s resale value (a good option if you’re planning to sell your house in the near future).

How much does it cost to repair a window seal?

Repairing the seal can cost anywhere between $70 to $120. Note that getting the seal fixed may also include replacing a window sash or having a double-paned window defogged. The amount will also depend on what other repairs you need, the size of the windows, and how many you need to get fixed.

To avoid surprises, it is best to get an estimate on how much you need to invest in repairs or replacements if needed.

Pro Tip: We highly suggest that you contact at least three window service companies so you can compare their prices. Also, if you’re getting a window replacement, it’s more cost-effective if you get multiple windows replaced at once as contractors would be willing to give you a discount when the volume of the job is higher.

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