Great Answers: Why is there condensation on my new windows?

I just replaced all the windows in my home. Why is there condensation on the inside of some of them?

Condensation is the process by which water vapor in the air turns into liquid water, and is most visible when there’s a large temperature difference between an object and the atmosphere. For example, a mirror after a hot shower or a glass of cold water left outside in the heat both produce condensation.

Although it’s usually harmless, condensation can damage certain materials over time, such as wood molding and plaster. Windows in a home are often susceptible to this type of damage, especially in regions with extremely high or low temperatures. Homeowner Connie Todarello noticed condensation on the inside of her recently replaced windows. Knowing that GuildQuality’s community of builders, remodelers, and contractors could provide her with more information, she turned to the Answers page to ask them about her situation. Here’s what they had to say:

“This is common with new windows that are sealing a home better than the old ones. Check to make sure the humidity in the home is at 30-50%, and wipe the water off the windows and window sills. Opening shades or blinds to allow air flow may also help.”

“Assuming the windows were installed properly and aren’t defective, you will likely find that over time, as the humidity inside your home balances out, the problem will go away.”

“I would recommend contacting a licenced heating contractor. Ask them to check the replacement air going into the FAU.”

“Excess humidity or water vapor inside a home causes “sweating” on windows. When this water vapor in the air comes in contact with a cold surface, such as a mirror or glass window, it turns into water droplets. All homes have occasional condensation, such as fogging on the windows, and is no cause for concern.”

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