After for and Against Comments for Controlling A/C?s

After for and against comments for controlling A/C?s (small wall spilt systems) with no add on voltage free controls for interface for simply on/off control.

In the past before IR control was around I use to switch full load current to the A/C unit via a voltage free relay through a contactor.

In terms of cost and ease of programming, which method do installers/programmers use?

Switch full load current to A/C with default set point at one temperature( so once mains is lost A/C will return to that temperature and wall remote is left in cupboard draw for small temperature changes)

Use IR control to control A/C?? (Anyone know the cost comparison in terms of programming Cbus and gear needed compared to other methods)

Any other methods commonly used?? (As these small spilt wall mounted systems don?t have an add on module interfaces)

Any info would be greatly appreciated.