Choosing the right size air conditioner for your bedroom is essential for a comfortable night’s sleep—especially during Brisbane’s hot and humid summers. A unit that’s too small will struggle to cool the space, while an oversized unit can cycle on and off too often, leading to clammy air and high energy bills. So, what size air conditioner do you really need for your bedroom?
Step 1: Calculate Your Bedroom Size
The first step is to calculate the floor area of your bedroom. Measure the length and width of the room in metres, then multiply those numbers together.
For example, if your bedroom is 3.5 metres wide and 4 metres long:
3.5 × 4 = 14 m²
Step 2: Multiply by the Cooling Factor
For rooms with standard 2.4 metre ceiling heights and average insulation, the general rule is that you need around 0.15 kW per square metre.
So in the above example:
14 m² × 0.15 kW = 2.1 kW
That means a bedroom of this size would require an air conditioner with at least 2.1 kW of cooling capacity.
Recommended Unit Size
For most standard bedrooms (typically 10–20 m²), a 2.5 kW split system is ideal. It provides just enough power to cool the space efficiently without overdoing it. If your bedroom is larger or less insulated, you might need to consider stepping up to a 3.5 kW unit.
Check out our full guide comparing options:
2.5 kW vs 3.5 kW Air Conditioners
Room Size Examples: What Size Air Conditioner Do I Need?
Use this quick guide to determine the right size air conditioner for your bedroom, using the formula:
Room Area (m²) = Length × Width
Required kW = Room Area × 0.15
Small Bedroom – 10 m²
Room dimensions: 2.5 m × 4 m
Calculation: 2.5 × 4 = 10 m²
10 × 0.15 = 1.5 kW
Recommended unit: 2.0 kW split system
Medium Bedroom – 14 m²
Room dimensions: 3.5 m × 4 m
Calculation: 3.5 × 4 = 14 m²
14 × 0.15 = 2.1 kW
Recommended unit: 2.5 kW split system
👉 Compare 2.5 kW vs 3.5 kW Units
Large Bedroom – 18 m²
Room dimensions: 3.6 m × 5 m
Calculation: 3.6 × 5 = 18 m²
18 × 0.15 = 2.7 kW
Recommended unit: 3.5 kW split system
Master Bedroom with Ensuite – 24 m²
Room dimensions: 4 m × 6 m
Calculation: 4 × 6 = 24 m²
24 × 0.15 = 3.6 kW
Recommended unit: 3.5–4.0 kW split system
👉 Compare 3.5 kW vs 5 kW Units
Extra-Large Bedroom – 30 m²
Room dimensions: 5 m × 6 m
Calculation: 5 × 6 = 30 m²
30 × 0.15 = 4.5 kW
Recommended unit: 4.6 kW or 5.0 kW split system
👉 Compare 4.6 kW vs 5 kW Units
Other Considerations
Ceiling Height: If your bedroom ceiling is higher than 2.4m, you’ll need more cooling power.
Insulation: Poor insulation allows more heat to enter the room, meaning your unit will need to work harder. In these cases, consider sizing up slightly.
Windows and Sunlight: Bedrooms with large windows or west-facing exposures may also need more power to stay cool during the hottest part of the day.
Unit Placement: For the most efficient cooling, your air conditioner should be installed high on the wall to circulate cool air evenly across the room.
Still Unsure?
Check out our detailed guide:
What Size Air Conditioner Do I Need?
For personalised advice and a free quote, contact the Brisbane air conditioning experts at
Advanced Climate Solutions today.
