Condensation on the Outside of Windows

Homeowners who have highly energy-efficient windows may notice condensation forming on the outside under certain weather conditions.

Why is my bedroom window covered in moisture early in the morning? This question is often asked by homeowners who have highly energy-efficient windows. This condition usually occurs in late summer and early fall when the night time temperature drops several degrees.

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.