By Bill and Kevin Burnett
Q: When double-pane vinyl windows are installed, should there be any condensation whatsoever on the outer windows? If there is, does that mean they are improperly installed and hot air is leaking out of the house? Or does it matter?
A: Condensation forms when there is a difference in temperature between the inside and outside of the glass. Some heat transfer is to be expected between the heated indoors, through the airspace between the two panes, to the colder outdoors. Double-paned windows will restrict that heat transfer, not stop it completely.
Condensation on the outside pane of glass is not abnormal, especially if the window is in a relatively humid area that gets little sun.
Based on what you've told us, no need to worry. Your installation is fine so long as there is no condensation between the panes or on the inside of the window.
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