Find a suitable air conditioner for your home with this buying guide. Learn everything you need to know about split system and portable units, so you can enjoy a cooler home environment.
How air conditioning works
Air conditioners typically cool air through a process that replaces hot air in a room with cooler air that has passed through the refrigeration cycle. The refrigerant absorbs and removes heat from the space and expels it outside.
Evaporative coolers lower the temperature of dry air through the evaporation of water. In extremely dry climates evaporative cooling also conditions the air with moisture to create a healthier environment.
Types of air-conditioning
- Split system: The cooling unit is installed outside with the heated unit (fans) mounted inside. A split system air conditioner is suited to cooling one or more adjoining rooms.
- Portable air conditioner: Small, light and mobile, the portable air conditioner is movable from room to room. Portable units have a lower power output (than a split system), and suited to smaller spaces such as apartments and where permenant installation is not permitted.
- Evaporative cooler: Air is cooled through the evaporation of water, which maintains healthy air moisture and offers an energy efficient alternative to conventional air conditioners.Evaproative coolers are suited to drier areas, normal away from the coast.
Technical Terms You Should Know
- Reverse cycle: The reverse cycle air conditioner internally reverses its operation to provide heating or cooling, as required
- Inverter system: Constantly alters fan and motor speeds. This enables faster cooling of a room, and the inverter air conditioner does not have to switch itself on and off to maintain a constant temperature
Smart Air Conditioner
Smart air conditioners offer additional features such as occupant and sunlight sensors, and some allow the user to remotely control the appliance from other devices.
Match the air conditioner to your room size
Finding the right air conditioner depends on numerous factors including room size, ceiling height, insulation, size of windows, level of sunlight and more. Below is an approximation of required cooling and heating capacities for different room sizes.
| Room Size m² | Capacity - Cooling (C)/Heating (H) |
| 3.0m x 3.0m = 9m² | 2.5KW(C)/3.2KW(H) |
| 5.0m x 5.0m = 25m² | 3.5kw(C)/3.7KW - 4.3KW (H) |
| 5.5m x 5.5m = 30m² | 3.5kw(c)/3.7KW(H) - 5.0KW(C)/6.0KW(H) |
| 6.3m x 6.3m = 40m² | 5.0KW(C)/6.0KW(H) - 6.0KW(C)/7.2KW(H) |
| 6.7m x 6.7m = 45m² | 6.0KW(C)/7.2KW(H) - 7.1KW(C)/8.0KW(H) |
| 7.1m x 7.1m = 50m² | 7.1KW(C)/8.0KW(H) - 8.0KW(C)/9.0KW(H) |
| 7.7m x 7.7m = 55m² | 8.0KW(C)/9.0KW(H) - 9.2KW(C)/10.0KW(H) |
Cooling capacity
It is important to match the air conditioning unit to the size of the room it is cooling. The bigger the room, the more cooling capacity and power input required. Under powered air conditioners will have to work harder, wasting energy.
Energy Efficiency
Energy efficiency for air conditioners is measured by capacity output in relation to power input. The ratio of power to cooling and heating capacity to achieve determines the energy efficiency of the system.
Often energy efficiency decreases between similar models as cooling capacity increases. The compact size of air conditioning units come at the cost of energy efficiency.
Additional considerations
- Air conditioning installation is best on the side of your house that gets the least sun, as direct sunlight can cause the unit to be less efficient
- Mount the air conditioning unit high for efficient cooling that allows the cool air to sink through the room
- Do not attempt to install a split system without holding the appropriate licenses, as this will void your warranty