My house is a small ranch style, no basement but a four foot tall, dirt floor crawl space. It is located on Narraganset Bay in Warwick, Rhode Island (a damp, flood-prone area). The house was built in 1956 and completely gutted and renovated in 1992. The renovation included new wood-frame windows, steel doors, plumbing, electrical, heating system, plaster over wallboard walls (replacing knotty pine), roof shingles, and vinyl siding. The heating system is gas with baseboards (hot water or steam?). Flooring is hard-woods and tile with wall-to-wall carpeting in bedrooms. There is a brick fireplace, (never-used) the opening is covered with a one of those brass and glass fireplace screens. Only one original window was retained and reused. It is in the living room and is a double-paned picture window.
Here is the problem I'm having. As soon as Fall arrives and we begin to use the heat, the windows begin to sweat excessively. It is to the point where the curtains become stained. Black mold (mildew) grows on wood parts of windows and on painted frames and sills. (Also brown spots-some other type of mold). The mildew also grows down the walls and along the baseboards under the windows. Mildew also collects behind furniture that is against walls in the vicinity of the windows. Along with all of this, fuzzy white mold and greenish-gray mold grows in the living room. The fuzzy white can be found all over the face and hearth of the fireplace and some wood furniture. The green grows all along the wall (from end to end) up near the ceiling of the wall the old picture window is on (this wall also includes the front door and is around the corner from the fireplace.) The green can also be found in corners on the wood floor in this room and under furniture. The picture window is the worst with the sweating, the frame is beginning to rot and is always black with mildew. I spend a great deal of time scrubbing and repainting this window and can never open the curtains because of it's disgusting appearance.
I hope I've provided enough details about the house and it's location to help with determining the possible problem. Any suggestions, diagnosis, solutions you have would be greatly appreciated as we are not financially able at this time for a professional evaluation. We'd like to try to fix things ourselves, but don't know what to do.