what size air conditioner do I need?

What Air Conditioner Size Do I Need?

With summer well and truly here and the Aussie heat creeping in, you might be looking at buying an air conditioner to keep you and your family cool. Buying the right unit can save you a lot in the long run and doing the correct research is extremely important! The wrong air con can mean higher power bills, fluctuating room temperatures and more maintenance than it’s worth!

But don’t worry! Service Today is here to help you understand how to find the right air conditioner for your home and how to maintain it! Ensuring you and your family keep cool for many summers to come! To help you make an informed choice, and so you know what size you need, here are our top key factors to consider.

Room Size

The size and volume of the room can help to determine how much power is needed to keep the room nice and cool. kWs is used to measure the output power of electrical appliances including air conditioners. A small room that is less than <20m2 will need 2 – 2.5kW units, a medium sized room around 20-40m2 needs 2.5 – 5kW, large rooms around 40-60m2 will usually need 4-6kW and an extra large room that is more than 60m2 needs a 5-9kW unit.

If the unit is too big, it may run frequent cooling cycles causing the temperature within the room to fluctuate. This means you will use more power and it will ultimately cause higher running costs. It will also result in unnecessary wear and tear of your cooling system. If the unit is too small, this can force the cooling system to run at maximum output, causing the air to be drier and also resulting in higher power use and extra wear and tear.

To save these headaches, use our room size guide above and speak to our team to ensure you are getting the best air conditioning system for your needs.


If your home has insulation, you won’t need as much power to cool your rooms! If your home doesn’t have insulation or is poorly insulated, hot and cold air can come through your walls, floor and roof. This means that you’ll need a more powerful air conditioning unit to maintain a consistent temperature. Your technician will be able to guide you through this.

As an example, a 30m2 room with roof insulation will only need a 2.2kW unit to keep the room at a maintained temperature whilst a room of the same size without roof insulation will need 3.4kW air conditioner. That’s quite a big difference!


The location of your home and rooms are another factor you need to consider when determining the best size air conditioner. Australia has a range of climates and each city is unique! Temperate climates such as Sydney, Perth and Brisbane, generally have lower temperatures and have a moderate climate. If you live in these areas, you’ll need less powerful air conditioners. If you live in areas that have higher fluctuations in weather such as Melbourne, Hobart, Darwin and Adelaide, you’ll need a more powerful unit.

The placement of rooms within the house is another key point. If the room has north facing windows, this space will become warmer due to sun exposure and may need more power to keep the space cool.

How to maintain your air conditioner

Neglecting your air conditioner can cause them to not perform properly, use more energy and in turn cause your power bills to increase. To maintain your unit and keep it clean and running efficiently, we recommend doing these steps:

  • Clean and change the unit’s filters every 1 to 2 months in summer as the filters help to purify the air and can become quite dirty
  • Dirt collects in the evaporator and condenser coils, so check them every year and clean as needed
  • Straighten and fix the fins to allow for maximum air flow
  • Air conditioners have condensation drains to reduce humidity and the collection of moisture. Clean the drains using a stiff wire to prevent clogging
  • Ensure that the seals between the air conditioner and window remain tight to reduce cool air escaping. Moisture damage can cause these seals to loosen

Professional Service

We recommend having your air conditioning unit serviced and cleaned every year by a professional to reduce your energy bills, increase efficiency and reduce mould and odours.


That sums up our top tips! Just remember, whether you are buying a new unit or looking to maintain the unit you have, getting an expert to assist you will save you time and money in the long run! Contact the team at Service Today for an on-site visit from our certified plumbers and technicians!