What Causes Film On Inside Of House Windows?

Owning a home requires a lot of maintenance. Most homeowners do not have the time or patience to complete all of the maintenance needs in and around their homes. However, the home does have a great way of showing you signs of repair. For example, when the inside of a house window has film or condensation. This can be typical as materials break down around the window. What causes film on the inside of house windows? A broken seal around the window allows moisture to access the double pane of the window.

Let’s take a look below at what else causes film on your windows.

Call a professional to help with foggy windows.

What Causes This?

The moment that you notice a film on the inside of your windows you can assume that the window seals have broken down. Film or condensation has started to build up due to the insulated glass unit (IGU) seal deteriorating. Double-pane glass windows have air in between the panes. Argon and Krypton are the air that typically is used by the manufacturer. This increases the energy efficiency in your windows. Let’s take a look below at what can cause these air seals to break down.

  • Excess heat – Living in an area where heat temperatures are extreme your window seals can break down faster. The hotter the temperatures the more the seals will expand and stretch. This allows air to get access to the inside of the windows.
  • Old age – If your home was built many years ago, the chances that your window seals are still good are not very likely. Over time, the seals break down due to extreme temperature changes and the continuous use of the window being opened and closed.
  • Water exposure – Water that puddles up near the outside of the window can eventually seep into the window panes. The water buildup breaks down the seals and will eventually allow the moisture to get access to the inside.

How Can I Prevent This?

If you want to prevent any film, condensation, or fog from forming on your windows, make sure to have them installed properly. Let’s take a look below at some other ways to prevent film buildup.

  • Add window protection – Installing a layer of film to your windows will help regulate the temperatures inside the home. Also, this can help keep moisture from getting between the windowpanes.
  • Window inspections – As a homeowner, it is important to walk around the home to inspect your windows.
  • Ventilate home – Create good circulation in the home. This ensures that warm air doesn’t stick to your windows.
  • Dehumidify – Using a dehumidifier removes all excess moisture from the home. This keeps the excess air from getting into your window panes.
  • Energy efficiency – If you are installing new windows, ensure that they are energy efficient. These types of windows will save you from using an additional 25% to 30% of wasted energy due to heat gained or lost.
  • Proper Installation – Hire a reputable window installation company to ensure that they have expertise with the installation process.

Other Recommended Maintenance

Now that you understand what causes film on your house windows, let’s look at a few other maintenance areas. One of those is the window leaks when it rains. This could be due to flashing that is missing, sealant that is cracked, or an issue with the gutters.

Sometimes when a homeowner is selling a home, they aren’t sure what they need to replace in the home to sell it. One area the seller wonders about is replacing windows before selling a home. However, it is not necessary and instead, replacing the caulking or weatherstripping is a good idea.

Lastly, you want to make sure that when putting stucco on your home, you choose a type that is allowed. One of the types is EIFS, which is exterior insulation and finish system. It provides high energy efficiency, is resistant to fire, and is waterproof.

Condensation on your windows should be fixed right away.

When Do I Call A Professional?

The moment that you notice a film on your windows, you will want to call on a professional contractor. In most cases, your windows just need to be re-caulked and sealed. However, in some cases, the film on the inside could be due to a faulty air conditioner. In this case, call on your local home inspection team before spending a lot of money. You might need window replacements, a new air conditioner, or something simple like new seals. Additionally, they can recommend a reputable contractor to complete the needs of the project.


Adjust the moisture levels in your home as you start to troubleshoot why there is a film on the inside windows. If drying out your home doesn’t fix the problem, it is time to call for a home inspection. They can come out and check on all of your windows and doors to ensure that the seals are still in good working condition. Also, they can recommend any other repairs that might be needed. Reach out to House Inspection Associates to conduct a full home inspection in the Virginia, D.C., and Maryland areas.

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