Air-conditioners come in 5 main types, and use different types of technologies
Ducted systems operate through your entire home from a series of ducts. They are efficient, quiet, and if installed in zones so you can turn different areas on or off depending on your needs. They have three components – an outdoor section, an indoor section in your roof space and a zone control box.
There is a wide range of choice in terms of capacity here, and they can be either cooling only or reverse cycle models (see technology below) to heat and cool. There are two components - the compressor/ condenser section outside the home and the ‘head’ unit that has the evaporator inside, circulating air.
This is the same as a split system but there are more 'heads' in different rooms, and you can adjust each 'head's' temperature. Usually between two and seven heads are installed.
With this type, everything is together and the air-conditioner is installed through an opening in a wall or a window.
These are mounted on wheels to be moved between rooms or packed away in the winter. They are most effective as spot coolers rather than full room air conditioners because they are generally not as effective as other types, and because the ducts must be put outside (usually through a window) this means that hot air is also constantly entering the area.
Air conditioning systems can be powered by electricity or gas and this means that is some states you may need an electrician, and in some states you may need a plumber.