Integration, more than any single component.

One supplier owns the whole air path.

One control system sequences everything.

One curb and one set of connections.

One warranty covers the outcome.

Coordination effort largely disappears.

Sequence recovery against mechanical cooling.

Recovery is not beneficial in all conditions.

On some mild days it adds to the cooling load.

An integrated unit can bypass or slow the device.

Separate components often simply run it always.

That difference shows up in annual energy.

When it moves heat the wrong way for the load.

Mild conditions with cooling demand are the case.

Exhaust air can be warmer than outside air.

Transferring that heat raises the cooling load.

Bypass or wheel speed control handles it.

Confirm the unit has that capability.

Flexibility and independence.

Capacities step rather than scale continuously.

Cabinet sizes come as the manufacturer makes them.

End of life means replacing everything at once.

Spares and controls come from one source.

That dependency runs for decades.

A large object with one position.

Weight requires structural checking.

A curb built to that specific model.

Clearances for airflow and for service.

Intake must not draw from exhaust discharge.

Settle all of it before ordering.

By whether filters and the wheel can be reached.

Both need regular attention.

On a roof that means safe access as well.

Panels must open with clearance around them.

A unit against a parapet loses one side.

Check the service side at layout stage.

Usually favourable once coordination is counted.

Component schemes look cheaper on equipment.

Design, installation and controls close the gap.

Commissioning is simpler and faster.

Compare installed cost, not equipment cost.

Flexibility is the real thing being traded.