Exterior Window Condensation

What is Exterior Window Condensation?

Just like condensation on the interior pane that most people are familiar with in winter’s colder months; exterior window condensation is moisture that builds up on the window’s outer pane of glass.

Why are my new highly efficient triple pane windows doing this?

It may seem natural to assume that something is wrong with the windows that you just purchased and were told that were your most efficient option.  With Efficient Triple Pane windows; condensation on the interior pane is probably an indication of high humidity or poor airflow to the glass (having window coverings closed at night is the most common reason you will see some interior condensation in the morning).

Condensation on the exterior pane however is slightly different and can be viewed as a good thing.  Water vapor in the outside air condenses on the outer pane of glass that has a surface temperature that is lower than the dew point.  The dew point is the temperature at which air becomes 100% saturated and produces dew/condensation.   Condensation forms on the exterior of your triple pane window because the tripane glass is very efficient and does not allow the warm air from inside of your home to escape through the glass to warm up the outer pane.  The outer pane of a dualpane window will always be too warm for condensation to form on the outside of your window because too much heat from your home escapes not allowing the outer pane of glass to be colder than the dew point.

Although exterior condensation can be a bit annoying, it typically only occurs in the spring and fall when temperatures are hovering around 0 Degrees Celcius and there is a transition from cool nights to warmer mornings.

In conclusion, condensation on the exterior pane of your windows can be viewed as something good and by putting up with it you are saving yourself money because of your highly efficient windows.

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