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What size split system do I need?

What size split system do I need? This is a very common question customers ask.

Hesitating what capacity of a split system need to be installed, here are some tips for you.

The range of most split systems starts from 2.0kW to 9.5kW which suitable to be installed in a small bedroom and large living room respectively.

Rapid Cold Airconditioning specialises in advising, supplying and installing Daikin and Mitsubishi Electric air-conditioners,

Daikin models range from 2.0kW to 9.4kW

Mitsubishi Electric models range from 2.0kW to 9.0kW

so there is always a capacity to suit most cooling and heating requirements around the home.

Below is a quick reference for selecting an air-conditioner in a particular room:

  • Bedroom (<20sqm) 0kW – 2.5kW

  • Small living room (20-30sqm) 5kW – 5.0kW

  • Medium living room (30-45sqm) 0kW – 7.0kW

  • Large living room (>45sqm) 0kW – 9.5kW

Although there is always a general guideline on how to select the capacity, the best way to determine what capacity is needed is to have a professional size the system for you. Our team will come and assess all the room requirements e.g., the size of the room, the height of the ceiling, the number of windows, the purpose of the room (gym or lounge) and the insulation within the walls, etc.

Buying the right capacity unit is especially important, not only to avoid the upfront expense on the electricity bill but also to have a longer lifespan of the unit.

If an over-sized air conditioner is used, then:

  • The room will often become hotter or cooler by too much
  • “short-cycling” happens, which means the air conditioner works too efficiently to cool down the space, the thermostat signals the unit to shut off, when the temperature rises again, the system turns back on, quickly cool down the room and repeat the cycle.
  • The frequent switching on and off leads to significant wear and tear on the system
  • More energy will be used on the frequent “on-off”, leading to the larger energy bill
  • “Short-cycling” doesn’t allow the air conditioner to remove moisture from the air as a result of discomfort

If an undersized air conditioner is used, then:

  • unable to cool or heat the space efficiently
  • The unit will consistently work and use more power to cool/heat to the desired temperature, resulting in paying more on bills
  • Overworking increases the risk of breakdown, experiencing severe wear-and-tear
  • The air conditioning unit will dry out the air more frequently


That is why the onsite inspection is needed to accurately calculate the unit size and provide the best solution to our customers.


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