I already have a ventilation unit, why is there still condensation on my windows?
The air exchanger is used to exhaust excess humid air in winter. Therefore, it is normal to see fog or ice on windows during cold weather. Many factors may contribute to this problem, such as: windows poor insulation quality, heating temperature, barrier in front of the windows (lack of ventilation near the windows caused by blinds, curtains, etc.), dominant winds, drastic changes in outside temperature, etc.
Do not wait to heat your home, especially in the basement. It will remove moisture that has accumulated during summer.