Air Conditioners Sizing and features

It is important to select an air conditioner with an output capacity to suit your particular cooling or heating needs.

Over-sizing can result in frequent cycling (turning on and off), which is inefficient, expensive and increases wear and tear. It can also result in cooling with limited humidity reduction. An undersized air conditioner will not provide adequate cooling or heating.

Air conditioner outputs are measured in kilowatts (kW), which is stated on the Energy Rating label. As an approximate guide for sizing a room unit, allow 125 Watts (0.125 kW) per square metre of floor area to be cooled in living areas, and 80 Watts (0.08kW) per square metre of floor area in bedrooms.

It is advisable to get a full heating and/or cooling load calculation from your air conditioning installer or manufacturer to determine the appropriate capacity. Floor area alone is not sufficient information to make an accurate calculation. Other relevant factors include ceiling height, window size, insulation levels and home orientation.

When selecting an air conditioner, look for:

• Programmable timer and thermostat controls. Set your air conditioner at the highest temperature setting at which you still feel cool enough, 25ºC is usually adequate. Each 1°C increase of the thermostat setting will save about 10% on your energy usage
• Movement sensors, which reduce power and energy usage when the room is unoccupied
• 'Set-back' and 'sleep' modes that automatically adjust thermostat settings
• Economy settings
• Multi-speed fans
• Adjustable and rotating louvres
• Remote thermostats and controls
• Inverter technology.