Duplex HVAC split issues

[Ashley Carson]

Hello everyone! Recently purchased a two story duplex. There’s 2 electric meters, but only 1 AC unit and 1 furnace. There’s only 1  thermostat in the downstairs unit. So the upstairs unit has no temperature control. What’s the best option for renting these units out? 1) remove thermostat and control temp for entire duplex remotely, 2)new furnace and ac unit for 2nd story unit, 3)???? Any help is appreciated.