Many homeowners are frustrated by condensation on the outside of their windows and wonder if this means that the windows are defective or were installed incorrectly. In most cases, condensation is completely normal and should be expected at times.
Condensation on windows often forms in response to differences in temperature and changes in dew point. Condensation does not usually indicate a problem with the window or installation.
How Dew Point Affects Condensation
The dew point is the temperature at which the air is completely saturated with moisture, or the air has 100 percent relative humidity. Condensation forms when the surface temperature of an object such as a window falls below the dew point. This means that the window is performing the way it was designed to do.
If the temperature is warmer inside the house than on the outside, the window blocks heat from being transferred to the outside of the house. The part of the window on the outside of the house is cooler than the outdoor dew point, and condensation forms.
If the interior of the house is cooler than the outside, the windows can still get condensation on the exterior if the cool indoor air penetrates into the spaces between the lites. The low-E coating can lower the temperature of the exterior lite to below the dew point, which can cause condensation to form.
Why Some Windows Get Condensation and Others Don’t
Sometimes only some of the windows in a house get condensation while others are clear. There can be several reasons for this. Condensation is less likely on a cloudy night or if there are trees, bushes, or other obstructions near the windows. The height and angle of soffits or other overhangs can also play a role in whether or not condensation forms on the windows.
Windows that do not have condensation can also have some energy leakage that warms the outside of the glass and raises the temperature above the dew point. The leakage could be minor and only needs to raise the temperature a small amount to prevent condensation from forming. A small change in the temperature or humidity can change the dew point and can affect the level of condensation.
Get a Quote for New Energy-Efficient Windows
If you are considering installing new energy-efficient windows in your home, contact Aladdin for an estimate. We install energy-efficient vinyl replacement windows and have been serving Connecticut homeowners for over 60 years.
