On cool, humid mornings in the summer, you may wake up to find moisture clinging to the outside of your windows. At first, this may cause alarm and appear as if the seal between the two panes of glass has failed. However, if the moisture is only on the exterior of the glass, it’s simply dew clinging to the glass and is perfectly normal.
Why Does Dew Form?
You may hear TV meteorologists speak about dew points during their weather reports. The dew point is reached when the temperature drops to the point that moisture in the air turns into water. On cool and humid mornings with no wind, it’s easy for the exterior of your glass to reach the dew point, resulting in dew on your window exteriors. with Low-E coating and other highly energy-efficient styles often accumulate dew on cool mornings as the Low-E coating prevents the home’s interior heat from transferring to the exterior pane of glass.
There are other factors that contribute to glass accumulating dew, such as large surface area of the glass (which is why we often see this on picture windows), a soffit or any kind of overhang above a window, plants or trees near a window, and the cleanliness of the glass.
It’s normal to see dew gathering on the exterior of your Renewal by Andersen windows or patio door on a cool spring, summer, or fall morning. As the sun comes up and warms the morning air, you will see the dew dissipate, leaving you with a clear view. The dew will not damage your window’s exterior in any way.
If you have any questions, please call our service number at (610) 849-2815.