1940's house 5k sq ft divided into 5 or 6 apartments
The upper level is controled by a lennox in the attic.
The lower is controled by a normal furnace systemn.
When we first got the contract for maintenance and this building the Filters looked 3 years old and the outside of all the ducts was covered with black mold. Inside were mold free. We cleanned the burners and replaced the filters with a 4 inch pleated in stead of the dime store cheap-o's. We cleaned all the mold off with bleach. When insulated with foil back.............. 3 Months later we stopped by to checked the filters and noticed the insulation on the ducts were wet and some had fallen down. and there as water all over the floor under all the main duct trunk. We checked the pressures on the A/c unit everything was fine.
The basement is just storage not climate controled. Can this be changed if we open a supply and a R/A ?
Any Ideas ?