Duplex on Concrete Slab, add HVAC or no?

[Medriand Arnold]

Hello BP, I am currently looking at obtaining my first property. The property is a duplex I am still working on, but there was something that struck me. Both units have window unit A/C. The house has never had HVAC and is on a concrete slab. I was wondering would adding HVAC be worth it. The house is worth about 140k ARV and rents are 850 around it. Current rent is 650. Both units are 2/1. The property is in Upstate, SC. Any help would be wonderful. Thank you.