Condensation appearing on the outside of the windows typically occurs on new windows with low-e glass and actually means that the windows are performing as they should be. The low-e coating reduces heat loss through the glass so there is less heat warming the outer pane of glass. In certain weather conditions, i.e. raised humidity, moisture in the air will condense on the outer pane of glass. If it occurs, homeowners should not be too concerned as it will not happen regularly and is not indicative of a problem with the windows.