Why Do Windows Sweat in Summer?

There are many valuable components found on the exterior of a residential structure — and windows are a major part of them. A well-designed and skillfully installed window unit can protect your family and interior belongings from inclement weather and scorching heat. It is also responsible for keeping your heating and cooling costs down to some extent. However, there is one window issue that concerns a lot of homeowners nowadays, and that is window condensation during summer.


An expert residential window contractor dives into the how and why of this specific occurrence.

What Is Window Condensation?

Condensation happens when there is a huge difference between indoor and outdoor temperatures. When warm, moisture-filled air hits a cold surface, it reaches a dew point and condenses. Inside your home, condensation or “sweating” typically occurs on window panes or the interior of windows.

Window Condensation in Summer

During summer, condensation on traditional or specialty windows begins when outdoor temperature is extremely humid and indoor air is relatively cool. Fortunately, this condensation issue is mostly visual. It is not entirely detrimental for your exterior windows to receive extra water since they are already exposed to rain and storm events. Condensation should disappear as soon as outdoor temperature rises up.

The Role of Low-E Glass

The main purpose of low-E coating is to minimize heat transfer from inside. If the indoor air is colder than the outdoor temperature, a Low-E coating will allow the temperature of the outside glass surface to drop. Meanwhile, if the outdoor air is colder than the indoor temperature, a Low-E coating will allow the outside glass to get even colder.

These events pertain to one thing — and that is, under the right circumstances, windows with low-E glass coatings can form more condensation than inefficient windows. This is a good indication that your home windows are working effectively.

If you are planning to give your exterior home a needed boost, turn to Renewal by Andersen® of Sacramento for a smooth and stress-free experience! We offer professional home improvement services — from casement windows replacement to French patio door installation. To start a conversation with one of our specialists, call us at (916) 779-5800 or fill out our online contact form. We serve areas in and around Davis, CA.