Is it required to have a switch to turn off the HVAC unit or is it acceptable to be wired directly
For an indoor furnace there should be a switch between the furnace and the furnace room door. In in a basement, and not in a separate room, a switch should be between the basement steps and the furnace.
At exterior AC or Heat Pump there should be a disconnect within sight and readily accessible.
A switch, or any other means of disconnecting power from the equipment.
A plug in the wall fits the bill in your area. Common in condo’s.
I think more explanation is needed…HVAC for one would not need a switch as you called it.
HVAC stands for Heating Ventilation and Air Conditioning so not all would need a “switch”
Direct answer is yes there needs to be a switch.
A means of disconnect is required. Bear in mind that the means of disconnect can be a breaker, if the panel is in direct view of the equipment.