Is it reasonable to sell a used furnace/AC?

[ender]

I have been considering getting geothermal. Cost is a major prohibiting factor but it occurred to me, if I replace my conventional HVAC that will leave me with a working AC/furnace. If I could sell those that'd defray some of the costs.

Are there decent used markets for this sort of thing?

[Cranky]

I’m sure there are - I know someone who bought a used hot water heater. Finding the person who wants it, and moving it, are likely to be tricky.

I am personally a big fan of donating things.

[msanne]

Where I am you see people selling them as good for a cabin or something like that. They don't seem to hang about the buy and sell pages long.

[EarthSurfer]

If I sold a unit, I would have the buyer sign an "as is" agreement stating the unit should be check for carbon monoxide leaks after installation.

I am concerned about the heat exchanger cracking on a furnace more than a few years old. Double that concern if it is a vertical flow furnace with an AC expansion coil mounted above. 

When I upgraded my rental units a few years ago, I parted out the old burner, valves, and a few of the safety switches on eBay for about $150 per furnace.