There is no "break in". It is not a car, nor does it have feelings nor does it need any foreplay! :eyebrows:
Just set the thermostat to cool and the desired temperature.
Here are a few Air Conditioning/Summer HVAC tips:
1. Set the thermostat temperature to the temperature you want. If you want 24C then set it to 24. It won't cool off any faster if you set it to 15. The thermostat is not a gas pedal. It is cruise control.
2. If you are away all day, it does in fact pay (costs less money in electricity) to dial back the air conditioning (set a higher temp) while you are not home, and then lower the temp when you get home. A setback thermostat is great if you have a regular routine. The new Nest or Ecobee or other internet enabled thermostats are good too if you want to lower the temp an hour or so before you get home so things are chilled down nicely.
3. If you have a basement, get a dehumidifier and attach a drain to run it into a floor drain. This will really help keep your basement dry and reduce risk of mold. It will also make for a nice dry, cool refuge!
4. If you haven't recently had your AC checked out, it is worth the $100 to have a guy come by to check the operation and freon charge.
5. If you have not already, think about washing the evaporator coil (inside the furnace duct) and the drain pan AND the condensate drain pan. These things get REALLY grungy and aside from the mold that can grow and get into your air (this is when people think they are "allergic" to air conditioning), cleaning the coil will increase the efficiency of your system. It can be a do-it-yourself job. Maybe check Youtube for a how to?
6. Rinse off the fins of the exterior condenser coils (outside your house).
7. Install a new furnace filter.
8. If you are away for the day, closing the curtains on south and west facing window will reduce passive heat gain and lower your electricity bills significantly.
9. Nowadays, with the cost of electricity going through the roof, it might be worthwhile checking out the newest high efficiency air conditioning systems. I think there are rebates from Hydro and the payback can be as little as a few years. One friend of mine got a high efficiency heat pump last spring and uses it to heat also most of the spring and fall and some warmer days in winter. I haven't done the math but he said that the energy cost per delivered btu/h is lower than natural gas until around -10C.