Most houses are designed and built with the heat ventilation sources at the outer perimeter and often under windows. This ensures that the air temperature will be higher in the vicinity of the windows with the desired effect of increasing condensation resistance. Care should be taken not to block the unrestricted movement of the warm air with furniture or other accessories. Doing so could increase the potential for condensation.
Stack Effect and Wind Exposure
Condensation is often worse on the second floor because of stack effect and wind exposure. Stack effect refers to the fact that warm air rises and therefore the warmer more moist air will be on the second story. Wind exposure means that the upper floor is more exposed to higher wind speeds, causing lower glazing surface temperatures. These two factors lead to more condensation on the upper windows in a house.
