Old homes and old HVAC systems bring the potential for asbestos — and a whole slew of potential liabilities for HVAC contractors and duct cleaning companies who handle it. Matt Mountain of Mountain Duct Cleaning explains what steps should be taken to protect both the homeowner and the duct cleaner or HVAC technician working on the system, as well as a couple workarounds — like cutting a branch of asbestos ductwork off from the furnace and installing a mini split instead.