Guide to Buying an Air Conditioner

There are several factors to consider when choosing an air conditioner. Here, we break it down for you:

  • Room size: Match the power of an air conditioner to the room size.
  • Type: Split systems
  • Filters: Prevent bacteria and allergens from being recycled through the room.

Room vs. Air Conditioner Capacity

Match the air conditioning unit to the size of the room. As a rule of thumb, the bigger the room, the more powerful an air conditioner will have to be to cool it:

  • Underpowered air conditioners will have to work harder, wasting energy
  • Overpowered air conditioners are an unnecessary expense

How Much Capacity Will I Need?

Air conditioners are rated by BTU (British Thermal Unit) and power output, in kilowatts (kW). To work out the approximate sized air con you’ll need, apply this simple formula:

  • Room: (L*B*75 BTU) = & BTU. For example, a room measuring 12ft*13ft will need an air conditioning of: 12*13*75 = 11,700BTU. Hence, 12,000BTU
  • Proximity to the kitchen and appliances increases a room’s required cooling
  • Room situation: If the room is situated on the top floor, the room is most likely warmer due to the direct heat of the sun. This will affect the performance of the air conditioner.

Technical Terms You Should Know in Air Conditioner

Inverter system

Constantly alters fan and motor speeds. This enables faster cooling of a room, and the air conditioner doesn’t have to switch itself on and off to maintain a constant temperature.

Energy Efficiency

Check the energy efficiency labels. Cooling-only air conditioners have one blue band of stars to display energy consumption.

Are Filters Necessary?

Yes. Good air conditioning units will use filters to prevent bacteria and allergens being recycled through the room.

  • It’s important to clean the filter every few weeks.
  • Units have an indicator to show when the filter needs changing.

Positioning Is Important

  • Avoid positioning the air conditioning unit on the side of the house that gets the most sun; this will cause it to be less efficient.
  • For efficient cooling, mount the unit high in the room — cool air sinks.


  • Do not attempt to install an air conditioner without holding the appropriate licenses. This will also void your warranty.
    King Bros provides installation services. Please contact us for more information.

Air Conditioner Selection

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