How to Stop and Prevent Condensation on Windows

Condensation on windows occurs when hot and cold air meet. While a bit of condensation is normal, it sometimes signifies a bigger problem, like a faulty seal.

If condensation is left to sit on the window for a prolonged period, it can lead to mold, rot, or cause your seal to warp. The methods to reduce window condensation depend on the time of the year and where the condensation has formed.

Top Causes of Window CondensationView in gallery

Here are the top causes of condensation and how to prevent it from recurring.

Top Causes of Window Condensation

Before correcting and preventing window condensation, you must know how it forms. The way condensation forms and where it develops differs between winter and summer months.


What Causes Condensation on Windows in the Winter?

While condensation can occur any time of the year, it’s most common in the winter. During the winter, the outside air is cold, while the inside is warm and sometimes humid. Since windows aren’t as insulated as walls, they’re a prime spot for the cold and warm air to meet, leading to condensation inside the window.


What Causes Condensation on Windows in the Summer?

In the summer, it’s more common to see condensation develop on the outside of the window. The leading cause of condensation in the summer is air conditioning. When the warm, humid air from outside touches the cooled window glass, condensation forms. 


What Causes Condensation Between Window Panes?

Condensation between window panes is the result of a leaky seal. If there is fog or condensation between your panes, you must replace the insulated glass unit or the entire window. The window is no longer air-tight.


What Causes Condensation on Windows in the Morning?

If you see condensation outside your window in the morning, it’s dew. Dew occurs when the outside air is humid, and your windows are colder than the dew point. Dew on your windows isn’t a significant cause for concern.


How to Prevent Condensation on Your Windows

Excess condensation leads to mold growth and rot. It’s important to wipe away condensation as soon as you see it and take the necessary steps to correct it.

During the winter:

  • Monitor humidity levels – Cold winter air is dry, which leaves many homeowners running a humidifier. If condensation develops on your windows, there’s too much moisture in the air, and you need to lower the humidifier’s settings.
  • Circulate the air– If only one room in your home experiences window condensation, run fans to circulate the air in the room. You can also use a portable dehumidifier to reduce humidity.
  • Install a window insulation kit- Lack of insulation is why windows collect condensation. A simple plastic window insulation kit can help regulate the temperature of your windows.
  • Add storm windows to single pane windows – Single pane windows don’t insulate as well as double or triple-pane options. Adding a storm window will help.
  • Use exhaust fans – Exhaust fans in the bathroom eliminate moisture in the air and keep humidity levels in check.

During the summer:

  • Monitor temperatures – If you’re experiencing frequent condensation, raise the temperature inside the house so the windows aren’t as cold.
  • Hang blinds or thick curtains – A thick, insulated black-out curtain can prevent the window glass from getting too cold.

Do All Windows Get Condensation?

All windows don’t get condensation. If you’re shopping for new windows, look for the “Condensation Resistance” section on the Energy Star Label. Condensation resistance measures how well a window prevents condensation on a scale from 1 to 100. The higher the number, the less likely a window will experience condensation.

Frequently Asked Questions (FAQ)FAQ

Should you wipe condensation off of windows?

You need to be vigilant about wiping condensation off of windows. Prolonged condensation can lead to mold, rot, and leaky seals.

Why is my window steamed up every morning?

If your windows look steamed up between the pains, you have a broken seal and need to replace the glass. You can do this by replacing your window or ordering an insulated glass unit from your window manufacturer.

Will an air purifier reduce condensation on my windows?

Air purifiers pull contaminants out of the air, not humidity. So no, an air purifier will not reduce condensation on your windows. Instead, you’ll need a dehumidifier.

Will heating help with window condensation?

Heating will not help with window condensation in the winter. Condensation occurs when hot air meets cold air at a surface. So the hotter the inside of the house in the winter, the more likely condensation will occur. Instead of raising the temps, run a dehumidifier to pull excess moisture from the air.

Will vinegar stop window condensation?

While vinegar is a good window cleaner, it won’t stop your windows from forming condensation. 

Is window condensation bad?

All window condensation isn’t bad. It’s only damaging if it’s constant, doesn’t get wiped away, or is between the window panes. 

Final Thoughts

A little condensation on the inside or outside of your window isn’t a major cause of concern. Wipe it away when you see it, and take steps to reduce the humidity in your house during the winter. And if there’s a little condensation on your windows in the morning – don’t worry. It’s dew that will evaporate as the sun comes out.

The biggest issue is condensation occurring between your window panes. Foggy window panes indicate a bigger problem with the seal. In this case, you’ll need to replace the insulated glass unit or the window.