Size matters when it comes to choosing the right aircon for your room in Toowoomba. An AC unit that is too big will be more expensive and may even bring unnecessary surge with your energy bills, especially during the summer season. However, choosing a small AC may not be sufficient to cool your space when you need it.

How To Calculate the Right Aircon Size for your Room


Let us guide you. Read on to know some tips on how you can calculate the right size of aircon for your room in Toowoomba.


Factors to Consider When Choosing the Right Size for Your AC Unit

Choosing the right size for your air conditioning unit is not an easy task. It requires you to consider the following factors:


Size of the Room

When considering the size of your room, you should think about the length, width as well as the height of the ceiling.

size of the room - calculate aircon size

Remember that a room with high ceilings requires more energy to cool.


Room Insulation

How much of the room is insulated? Does this include both walls, ceilings and even the ground?

room isulation - calculate aircon size

Know that one of the biggest factors in keeping your home thermally efficient is ceiling insulation.


Window Orientation

Depending on where your room faces can also affect your choice of aircon system. For one, a room with a north or west facing window will be more exposed to the summer heat compared to a southern facing window.

window orientation - calculate aircon size


Degree of Shade

Aside from your window’s orientation, you should also consider the degree of shade it receives. So although a north or west window will be more exposed to heat, if it has a tree that provides shade to it, then it will lessen the amount of heat getting into your room.

degree of shade - calculate aircon size


Let us now start with our calculation

To calculate the right aircon size for your house consider these steps:


Step 1: Calculation for the total floor area of daytime living areas

Daytime living areas include the following:

  • Lounges
  • Media
  • Hallway
  • Stairs
  • Family rooms
  • Kitchen

Based on all these locations, measure their floor areas.


Step 2: Calculation for the Ceiling Height

As mentioned earlier, the height of the room is a plus factor in determining the right size of AC. Measure the maximum ceiling height of your house, so you can proceed with the next step.


Step 3: Multiplying the Ceiling Height, Floor Area and Watts

Now you can have a glimpse of how much capacity of aircon you need to consider.


Simply multiple the total daytime living area with the ceiling height and your estimated watt usage. As a guide you may follow this:

  • [> Ceiling height of 2.4m but no more than 2.7m] x [total daytime living area (m²)] x 150 (watts)
  • [Ceiling height of 2.7m] x [total daytime living area (m²)] x 160 (watts)
  • [Ceiling height of < 2.7m] x [total daytime living area (m²)] x 175 (watts)


STEP 4: Convert the result to kilowatts

Now that you have the result, just move the answer three decimal points to the left for it to be converted into kilowatts.



The best way to get the right size of aircon for your room, office or house is to ask an aircon specialist about it. Schedule an appointment with us so we can come and visit your home. We are happy to help so you can have the perfect air conditioner this summer season.