Convert hvac on a 32 unit apartment complex

[Brit Baxley]

Just a bought a 32 unit apartment complex. Boiler heat to all the rooms. We’re thinking about converting everything into split unit hvac since tenant pays electricity and boiler is getting old and costs a lot to maintain and run heat through four stories. Does anybody have advice on the best way to make the change? Is there a better option than split units in all the units?