(Imagine emptying a 40gal heater, or cutting trunk and return ductwork, for an item with a serial number on it.

To replace them and add ductwork is expensive. 

In addition, all of the ductwork for the forced air furnace had to be removed and replaced as it could not be cleaned thoroughly enough to remove the residue.If there are three of them smoking several times per day exclusively in the bathroom, you might be looking at a new bathroom.

Unless ductwork is exposed in a crawlspace or unfinished basement, its difficult to balance.

Its a big job grinding(diamond cutters), patching, polishing(finer diamond cutters), staining and sealing a concrete floor.I could see it in a converted warehouse setting with open floor plan, sandblasted heavy timbers, and painted industrial ductwork, etc.

But it's all negotiable.Make the seller aware of the replacement duct work issue and provide your quote.

Structure is great, newer duct work, western cedar exterior and over all great shape.

They can make it out of aluminum much like they would duct work.

There was a rat problem,so I replaced the ductwork and only gitted the kitchen.

The main difference between these two properties was the ductwork and electrical work inlaid throughout these walls on the second property.