Kevin,If the furnace (implying forced air) is questionable, why not leverage the existing ductwork and install a heat pump?  

A lot of stuff is included but not installed like 4 new forced air furnaces, ductwork, water heaters, PEX, some drywall, and miscellaneous hardware.

asbestos on pipe or duct work in the walls - undisputed is fine.

Now, getting ductwork allergen free is another thing to include :)

Make sure you check out ductwork.

It also helps to clean the AC duct work.

I've just had a 3 ton electric system installed, with all of the ductwork for $ 4200I had a 2.5 ton electric system, with existing ductwork for 3200It all depends on the size, the system and the hvac company

The cost of installing 2 units and duct work was around $13k. 

Come to find out there were air handlers and duct work in each unit and A/C too, the kicker is, the heating portion was electric elements, not gas.

The ducts, ductwork, filters and even walls and ceilings near the ductwork can be contaminated.