Air Conditioning Size Calculator

Free Online AC Size Tool

How much for air conditioning repair

Disclaimer- This air conditioning size calculator can only gauge rough estimates to help you determine your approximate air conditioner size requirements. This size guide should not be considered a replacement for expert advice. The actual size may depend on other factors such as climate, number of windows, blinds and curtains, insulation rating, etc.

What Size Air Conditioner Do I Need?

If you’re looking to work out the correct size of your ducted or split system air conditioner, you can use our room sizing calculator below as a guide:

Room Length: 0 m
Room Width: 0 m
Split system AC
Split System AC
Multi Head AC
Multi Head AC
Ducted Refrigerated AC
Ducted Refrigerated AC
Air Conditining Size (kW) Table
General Formula

Air Conditioning Size Formula

To find the size
of Air Conditioning required for your daytime living area, you need to start by finding out its area. This is SIMPLE.

Begin by taking the length and width of each room and multiplying them. Then, simply add the area of each room to get an answer in square metres.

A general formula is Room Size (m2) x 150watts = AC Size

Please note that this is just an estimate for what size Air Conditioner you need.

If you want to cool a particular room and don’t know about the right size Air Conditioner, please refer to the room size table.


For more enquiries about Split System Air Con Installation in Melbourne, please contact ComfyHome on 1300 266 394 or submit a Free Quote Form Online.

Split system air conditioning installation

These factors can significantly affect the efficiency of your air conditioner. That is why it is crucial to take them into account before choosing the right size AC. If you have any doubts, consult with an HVAC professional who can evaluate your home and help find the right-sized air conditioner.

What Are the Factors Affecting Air Conditioner Efficiency?

To ensure you’re cooling your house as efficiently as possible, it is imperative to get the right size of air conditioner. Although the size of your air conditioner does matter a lot, it is NOT THE ONLY FACTOR to consider when sizing your Air conditioning system. For example, if your best friend or neighbour has the same sized home as yours, you might have to consider a different size AC due to a shady tree or more windows facing the afternoon sun.

Keep in mind that the following factors could affect your air conditioner’s cooling efficiency:

  • Insulation of the home
  • How hot and humid it gets in the summer months
  • The amount of shade and/or sun your home receives on a daily basis
  • The number of windows and their design, age and insulation efficiency
  • Ceiling height, as the total air volume inside has an impact on the efficiency
  • Condition of pre-existing ductwork in your home
  • The number of residents in the room at one time
  • Roof material (tiles or tin)

Does Air Conditioning Size Really Matter?

YES, the size does matter when it comes to Air Conditioning. However, this doesn’t mean that a bigger size unit will get the job done better. Bigger is not always better, and the same goes for a smaller unit as well.


Too Big

Too Small

Too Big

An oversized air con will result in short-cycling on and off frequently to reach the desired temperature. You could end up with an AC with high power consumption.

This will result in:
  • Uneven temperatures (too cold / too hot)
  • The air conditioner will begin to short cycle
  • Increased humidity levels, as the system will only run for a few minutes
  • Poor indoor air quality
  • High power consumption (increase in running cost)
  • Shorter lifespan of AC (more wear and tear)

Too Small

On the other hand, a small unit will fail to cool the space properly and will never stop running.

This will result in:
  • More frequent overheating
  • Inconsistent temperatures
  • Failing to cool the space properly, causing it to run all the time
  • Increased dehumidification due to constant running
  • More wear and tear due to continuous running
  • High power consumption

Whether your Air Conditioner is too big or too small, it can drastically reduce the unit’s lifespan. What should have lasted 10-15 years might not make it that far. In other words, size does matter to some extent, but choosing the right size matters the most.

Look for AC Installer

Look for a Professional AC Installer

Whether you need help choosing the right size Air Conditioner or installing it, hiring a professional AC installer will ensure your system’s efficiency and longevity. In Australia, it is essential to hire an expert Air Conditioner professional to install your AC. After all, they have years of relevant training to back their services. They are also licensed to handle refrigerants and minimise the risk associated with their use, such as flammability, toxicity and physical hazards.

Another reason to look for a professional AC installer is that the Australian Refrigeration Council issues two licenses – a restricted ‘splits’ License or a Full Refrigeration and Air Conditioning (ARC) License – one of which must be acquired by an AC expert. Furthermore, installation by a professional is mandatory for manufacturer’s warranties, ensuring you’ll be covered in case anything goes wrong.

Are you looking for a professional air con installer in Melbourne? Contact ComfyHome on 1300 266 394 or submit a Free Quote Form Online.

AC Size Isn’t Everything

While AC size matters, it is not as important as most people think. A lot more goes into choosing the right air conditioner for your home or business than just the kW rating. In fact, you can find other factors negating the common perception that AC size is everything.

Here is what you need to consider before selecting the best cooling solution for your home:


AC types of system icon Types of Systems

Depending on your cooling needs, you can choose from different types of air conditioning systems, such as Split System Air Conditioners, Multi-Head Split System Air Conditioners, Ducted Refrigerated Air Conditioning, Portable Air Conditioners, and others.


AC brands icon Air Conditioner Brands

There are many reputable air conditioning brands available on the Australian market. While some offer an astounding energy star rating, others provide a variety of features for optimal comfort. If you are after quiet operation and high efficiency, Mitsubishi Electric or Daikin may be your best bet. Air conditioners from brands such as Daikin, Fujitsu and ActronAir are also considered highly efficient.


Energy Efficiency Icon Energy Efficiency

The energy efficiency rating is an important factor that needs to be taken into consideration when buying an aircon. The energy efficiency ratings for air conditioners are based on a 10-star scale. If efficiency matters to you, consider an inverter air conditioner, as they can regulate temperatures more efficiently without starting or stopping.


AC system Extra Features icon Extra Features

Air conditioners with more features tend to be more expensive. Some common features that you need in a new air conditioner include a dehumidifier, reverse cycle, smart connectivity, air filters to remove odours, anti-fungus, turbo cooling, rustproof base pans, remote control, and timer.

Air Conditioning Promotion

Brands We Recommend

Why Choose ComfyHome Heating & Cooling?

ComfyHome Heating & Cooling adheres to a customer-centric approach in a bid to provide premium Melbourne heating and cooling solutions that fulfil your needs and align with your budget. We bring you convenience, affordability and quality of service you won’t find anywhere else.

Map icon
Servicing Melbourne-Wide
Star icon
40+ Years In AC Industry
Insurance icon
6 Years Installation Guaranteed*
Satisfaction icon
100% Customer Satisfaction
House icon
Customise In-House Design Solution
Certificate icon
Licensed, Insured Techs For Your Protection
Heart icon
Competitive, Honest and Affordable Quotes
Warranty icon
9 Years Manufacturer Warranty*

How Can We Help You Today?

ComfyHome services range from sales and installation of a comprehensive range of heating and air conditioning systems through to servicing and repairs to keep your system working optimally.

Our Happy Customers Say

Google Reviews Write a Review
Reviewer icon Antoinette From "Kew - Melbourne"

What an amazing Team, my elderly parents ducted heating stopped working and ComfyHome Heating and Cooling were so helpful and understanding, they got my parents heating unit installed the next day. Rob had the best customer service and Rodney who replaced the unit was amazing, professional, did a great job! Thank you and so happy and warm again.

Reviewer icon H Bailey From "Oakleigh - Melbourne"

What a fantastic company. The lovely repair person turned up on time and figured out what was wrong with our heating/cooling system in seconds. The cost was extremely reasonable. We had previously been quoted over $1000 dollars for a heating service by a different company and thought we were being ripped off… Definitely recommend!!!

A ONE-STOP SOLUTION For All Your Heating & Cooling Needs