Thermostats should be set between 25–27°C. Every 1°C lower can increase running costs by up to 15% or cost you for repairs because they do like a break every so often.

If there is a hot day forecast, then pre-cool your house the night before. This is especially effective if your house has a high thermal mass such as solid brick.

This will allow your air conditioner to work at its optimum during the cool evening, saving power and wear and tear on the unit. It also allows the unit to keep on top of the heat load as it begins to warm up during the heat of the day.

Power kilowatts and Refrigeration kilowatts

Electrical input wattage or Hp, and refrigeration wattage are two different things.

A unit drawing 746W (1Hp) of electricity may move 2 to 3.5 times that in cooling or heating wattage. Only the latter refrigeration kilowatt (kW) rating will give an accurate representation of unit size.
Input power conversions.

The old adage ‘You get what you pay for’ exists for a reason. However, some of the cheaper brands can provide excellent value for money and offer very good performance. Final decisions should be based on specific unit performance and value for money and running costs. There is very little difference between the mainstream and top units sold these days. It's only in the very cheap units that quality begins to suffer.