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Window Condensation: When It Is and Isn’t Normal

Condensation can occur in windows no matter the season. While being a common occurrence, it remains a typical cause of concern for homeowners. Your windows can sweat for various reasons, and sometimes it can be a sign of an issue. For instance, when condensation occurs inside the glass, it often means you need to get a window replacement

Window Condensation

Read on to find out what causes window condensation and if you should worry about it.

Why Does Window Condensation Occur?

When there is a significant difference between indoor and outdoor temperatures, window condensation occurs. There is more moisture in warm air than in cool air. Once the moisture in warm air lands on the cold window surface, it will settle on that area, forming condensation.

Where condensation develops depends on the temperature outside and inside your home. For instance, in summer, when it’s warmer outdoors and your air conditioner is running, condensation forms on the outside of windows. On the other hand, in winter, it forms inside because it’s colder outdoors and warmer outdoors. If you see this kind of condensation on your sliding windows, you don’t need to worry because it will eventually evaporate and go away on its own.

When Should You Contact Professionals?

Have you noticed condensation forming between the glass panes in your windows? If so, you must contact professionals to have them checked. Often, this fogging occurs because the unit’s seal has been compromised. It means that the inert glass that gives the window its insulative properties has already escaped, causing it to lose its energy efficiency. Depending on the state of your windows and their age, they may require replacement. 

At Renewal by Andersen® of Montana, we offer top-notch window replacement services. Whether you need casement, double-hung, sliding or picture windows, you can count on us. Give us a call at (406) 259-3944 or fill out our contact form to request a free quote. 


"I highly recommend Renewal by Andersen. We were treated well and everything went smoothly from start to finish. The company kept in contact with me before, during, and after the installation and let me know what to expect. I'm in love with my new windows! I will be using this company again when we refinish our basement. "

July, 21

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