Heat/AC replacement cost

[Aleksandra Brown]

Bought a rental property that isn’t too big. 2,000 Sq ft or so but has 2 heating units. One isn’t working. Had a guy come out and this is his quote 

“Remove old equipment and replace with 2 ton heil straight AC outdoor unit 2 ton heil indoor case coil. Heil 70000 BTU 80 plus gas furnace. 10 year compressor 5 year parts 1 year labor warranty $4100”

I didn't expect this much and don't understand it. These units only cover 1/2 the house. The other 1/2 has its own units. We have another rental that he is servicing but it was only a few hundred for cleaning and stuff. I'm in Blacksburg, VA. Anyone in this area know of average costs for this? Considering getting another opinion but husband says this guy is fine.
Thanks