Help re replacing ductwork

[Dee18]

I live in an 85 year old Craftsman bungalow, about 1600 sq ft, one story with a basement (part cement floor, part dirt covered in layers of plastic). the basement is dry, but humid year round here inthe southeast. I have had allergy problems since moving into this house.  Had it tested for mold and they said nothing troubling found.  what they did discover is that the ductwork is metal insulated with what looks to me like old carpet that is glued to the metal on the inside...where of course it has trapped dust and other allergens for the last many years.  the trunk line is a loop, so it must be at least 100 feet, with about 10 smaller lines to the vents.   The heater is huge and ancient, but still works well (my bills are less than half that of my neighbors...but then I am a baby moustachean). AC also works great, much newer.  so, my questions are- any ballpark estimates about replacing the ductwork? Is this something for a skilled DIY (boyfriend quite good at mechanical/plumbing/minor electrical)? any other suggestions?  Have done all basic allergy remedies- hardwoods throughout, leather furniture, minimal curtains, etc.

[Greg]

All ducts will collect a film of dust inside over the years.  Before replacing them, try having them cleaned.  Often this is done by reverse-vacuuming via the intake at the furnace, and blowing back through the registers.  There are also special filters you can add, including filters at each register.  I'd try this before replacing the ducting.

If there's a season you don't use the heat or A/C, compare your symptoms during these times to when you're using the heat often.  This will help determine if the furnace use is related.

If you still want to replace them, be sure to test whether or not the padding you see contains asbestos.  If so, you will have to be very careful removing the old ducting.

[Dee18]

thanks.  I had not thought about asbestos, but given the age of the house that's a possibility.  did look into cleaning and they said they could not do it with the padding.  I had that done at my former house and it helped. 

[TrulyStashin]

I had the tile floor in my basement tested for asbestos so maybe this is helpful . . . you can Google search "asbestos testing" for your town and likely find a lab that will do it.  It's not expensive.  The tile and the mastic each cost $7 for a total cost of $14 to find out that, yes, the tile is 2% asbestos but the mastic is asbestos-free.

A worthwhile investment.  Now when we remove the tiles, we'll be sure to take appropriate precautions which is not hard because the tiles are not "friable" (aka crumbly).

If there is asbestos in the padding it is likely very friable and thus more hazardous.  If so, it is not a DIY job that I would be willing to do.  I hope, for your sake, that the padding doesn't have asbestos.