The answer depends on a couple of things, including whether or not the unit is well suited to the room it’s installed in (see the previous question for help on that issue).
Other things being equal, buy a unit with the highest star rating for the power output you need. The more stars it has, the more energy efficient your air conditioner is, the less it will cost you in power bills and the less damage you are doing to our environment.
Compare the energy efficiency of units you are considering at www.energyrating.gov.au or look at the Energy Rating Label on the product.
No matter how good your system is, or how well it has been sized to suit the room, it won’t operate efficiently if it is poorly installed. This will reduce the system’s cooling and heating capacity, increase your electricity costs and shorten the life of your system.
