Our furnace filter is now picking up a thick black film and some of it is being circulated through the registers onto the sheer curtains. The filter was washed 5 weeks ago as part of the housecleaning. The filter was very regularly cleaned partly due to having had dogs, but it was never black like this; it is an actual black deposit and started appearing 4 - 5 months ago. Both my husband and I have been under medical care for skin rashes and eye inflammation for about a year. We had the ducts cleaned November last year. The house was built in the '60's. The forced air gas furnace was replaced approximately 7 years ago. We run a de-humidifier in the finished basement throughout the warmer months.
Answer:
This is a furnace that is badly in need of immediate attention. Get a technician in there as soon as you can because if may very well also be feeding carbon monoxide (lethal stuff) into the house.
