What about condensation on the outside of my windows?

Homeowners who have highly energy-efficient windows may notice condensation forming on the outside of their windows under certain weather conditions. This question is often asked by homeowners who have highly energy-efficient windows. This usually occurs in late summer and early fall when the night time temperature drops several degrees – much like dew forming early in the morning.

The moisture on the outside of the window is condensation. It will soon evaporate when outside temperature rises. As we know, condensation happens on cold surfaces. During the night, if the outside temperature drops below the dew point then condensation forms. The fact that the condensation is forming on the windows means that very little heat from inside the house is escaping through the windows. That’s a good thing and proof that you have energy-efficient windows.