I may be buying a house that was built in 1967. Inspection found most of the heating ducts are in bad shape and should be replaced. For a 1,700 square foot house, single story, duct access is in the crawlspace beneath the house -- would replacing the duct system be several thousand? Over $10,000? I realize you can't give a precise answer without inspecting the house, but I am just looking for a very ballpark estimate to give me an order of magnitude.

And if the current ducts are insulated with asbetos liners, there would be additional cost to have a specialty firm remove the asbestos, no?

Thanks in advance for any help you can provide.