We all like getting value for money. With air conditioning there are a huge range of choices all with different costs. The choices range from ducted system with the capacity to do the entire house to a smaller zoned unit which concentrates the air into the occupied area at the time. eg: cool common areas during the day and the bedrooms at night, to split system air conditioners which are installed only in the rooms required to be conditioned. Then there is the choice of brands. This varies from the premium brands such as Daikin or Fujitsu to the budget Chinese brands such as Haier which are less expensive.  All these units offer similar warranties, 5 year for domestic installations and 1 year for commercial.