What temperature should I set my air conditioner to?
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.
That is debatable 24–26°C