Generally (in a high-rise) the units are fed a steady stream of ‘supply air’ at 50 F or so, and heat pumps in the unit itself control the climate in the unit.

Generally (in a high-rise) the units are fed a steady stream of ‘supply air’ at 50 F or so, and heat pumps in the unit itself control the climate in the unit. HVAC needs to run constantly in these buildings as they’re sealed and need airflow for air exchange. Air isn’t heated and then sent thru the ducts in a high-rise building.