Forced air furnace install in 2 story MN house

[Dan Vleck]

I put in a cash offer today on a sfr rental foreclosure where the boiler and all the pipes froze. Plumber took a look and suggested it would be a good time to switch over to gas forced air furnace. I didn't have time to get an estimate for that, so I estimated $10,000. I'm wondering if I can save some money by doing some of the work myself or if a contractor has to do all the work. It is a two story with basement and all 3 bedrooms upstairs. Any diy people work on hvac system?