Hello, I am looking for some expert advice from indoor air quality experts here in the forum. I have an apartment complex that was converted from a resort to apartments. The buildings are concrete construction built in the late 80's. The apartments have old style single pane glass windows. The load bearing walls are concrete. Thr non-load bearing walls are drywall and metal studs. With insulation. The lid is 6" of concrete between floors and the ceiling as well. The HVAC system installed are old style Red "T" Coil units. They are 2 to 2-1/2 ton cooling split systems with strip electric heat. The bathrooms have one standard vent fan with lights controlled by a switch. The problem is excessive winter humidity. It is so severe that the walls condensate and create black mold in the corners and especially on all the window sill ledges. Previous management has tried to install Broan humidity sensing fans with sensors in the bath vanity, kitchen, and in front of the small laundry areas to remove humidity. The previous management has been treating the surface mold on the walls and sills. My question is; what is the best approach to resolve the humidity issue knowing the type of construction. Are the humidity sensing fans the way to go? I am looking for some expert advice.