Condensation and temperature fluctuations are usually the culprits in fogging up your windows. But, if you see foggy windows in your home consistently, it might be a sign of potential trouble.

Foggy windows indicate that there’s a problem with the insulation of your windows. In normal circumstances, a window’s seal and its insulation should prevent fogging. But if that’s not happening, you might need to rectify the poor window insulation or get a complete window replacement done.

What causes foggy windows at home?

condensation in windows

When the seal around your insulated windows is damaged, you see fog on the panes. The seal may break because of any of the following reasons.

  • Water damage after a flood or a heavy rainstorm.  The excess water buildup near the windows may damage the perimeter seals.
  • Excess heat and direct sunlight may make the warm air inside a double-pane window expand – stretching the window seals.
  • Old window seals, since they withstand the opening and closing of the window and harsh temperatures, may deteriorate over time.
  • Cold air may seep in through the glass panels, mix with the warm air inside and cause condensation and fogging. 

How to repair foggy windows?

If you’re looking for ways to fix windows that are perpetually foggy, the ideal solution would be to replace them altogether. Having said that, there are a few things you can try to repair your foggy windows.

  • Replace the window’s insulated glass unit (IGU unit).
  • Replace the seal inside your insulated glass window. Keep in mind that this process is more complicated than replacing the window. 
  • Use a defogging spray to prevent fogging on your windows. Here’s a hack: You could spray some shaving cream to treat window fog.
  • Opt for professional defogging. Its cost is about half of a window replacement cost.
  • Replace the window if nothing else works. 

Why are foggy windows not a good idea?

Insulated windows have two or more panes of glass, with inert gases such as argon or krypton between the panes. Well-insulated windows will make your home energy efficient by keeping the air inside your home temperature-controlled. You’ll need to ensure that the window insulated glass unit (IGU) is in good condition and increases the R-value of your glass window and its energy efficiency.

Moreover, old windows without good insulation could raise your energy bills every month without you realizing it.
Also, remember that foggy windows may become a danger to you and your family members over time as the excess moisture content could lead to harmful mold growth. 

How to prevent windows from fogging up?

fog in windows

Correctly installed windows should typically last for decades and give you a clear view of the outdoors. If you want to get the most out of your windows and prevent them from fogging, you must take a few steps.

  • Buy high-quality, energy-efficient windows that come with a lifetime warranty on seal failure. 
  • Make sure your window installation has been done correctly by a licensed professional.
  • Conduct regular window inspections every couple of months by checking for any signs of deterioration in your windows, sash, and seals.
  • Ensure good air circulation or ventilation throughout your home. Invest in a good dehumidifier that removes moisture from the air – preventing the air from getting between your window panes.

How can you keep excess moisture out of your home?

You should make an effort to keep moisture out of your house to extend the life of your windows. Here are a few ways to control the moisture content of your living space:

  • Make sure you use a fan while running the dishwasher, washing machine, or dryer.
  • Always cover your pots and pans while cooking.
  • Ventilate your home by regularly opening the doors and windows in all rooms and letting in fresh air for at least a couple of hours.
  • Make sure you have sound home insulation, especially in the attic and closet spaces. Weatherstrip your walls and doors properly.
  • Utilize the kitchen and bathroom exhaust fans – especially while cooking or showering.
  • Regularly inspect the air registers, outdoor gutters, fireplaces, and air vents to keep the ventilation going. 

Last thoughts

The primary reason for fog in double and single-pane windows has to do with temperature fluctuations and the air’s moisture content. 

But if you see your windows foggy all the time – regardless of the temperature outside – you may have a problem at hand. It could be poor window insulation due to broken seals. It’s a good idea to hire a professional to inspect your windows and take the necessary steps to rectify the issue.

Remember that foggy windows eventually lead to water droplets, which can ruin your window sill and encourage the growth of mold and mildew. Even the area rug and flooring beneath the window may get impacted. All these are best avoided. 

The solution is to ensure good ventilation and window insulation. And yes, updating the existing windows to energy-efficient ones will prevent air leaks and heat loss, reduce your energy bills, and keep the fog away. 

How to prevent foggy windows at home? was last modified: January 3rd, 2023 by Ramona Sinha
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