My wife and I bought a 50's vintage home with single pane double-hung windows. In general, it is very well-built. However, we occasionally get moisture/condensation on the inside of two of the windows, in two different rooms on the east side of the house. None of the other windows seem affected. It happens mostly on more humid days, but sometimes on less humid days as well.
So...What causes this condensation? What can be done about it? Appreciate advice.
NOTE: The occurrences were on moderate temperature days in which neither the A/C or heat were even on.