How Do I Choose the Correct Size Air Conditioner?
Wondering which air conditioner will keep your space perfectly cool? Picking the right size matters. A unit that’s too small leaves you sweating and your unit working overtime, while one that’s too big can drain your wallet with high energy bills.
The good news? With the right guide and expert advice, choosing the perfect aircon size is quick and easy.
Quick Guide to Finding the Perfect Aircon for Every Room
The size of an air conditioner is measured in BTUs (British Thermal Units). The higher the BTU rating, the larger the area the unit can effectively cool.
To calculate your room size, multiply the room’s length by its width to get the square metre size. Then multiply that figure by approximately 600 BTUs per square metre.
Each aircon unit on our website specifies the recommended room size it is suitable for, making it easy to choose the right option.
Match the Room Size to the Right BTU
9000 BTU Aircon
Ideal room size: Approx. 10–15m²
Example room: 3m x 4m
A 9000 BTU air conditioning unit is perfect for small rooms such as bedrooms, home offices, studies, or small lounges.
12000 BTU Aircon
Ideal room size: Approx. 15–25m²
Example room: 5m x 4m
A 12000 BTU air conditioning unit is suitable for medium-sized spaces such as larger bedrooms, dining rooms, or small open-plan living areas.
18000 BTU Aircon
Ideal room size: Approx. 25–35m²
Example room: 5m x 6m
An 18000 BTU air conditioning unit is ideal for large rooms, including spacious lounges, entertainment areas, and medium-sized offices.
24000 BTU Aircon
Ideal room size: Approx. 35–45m²
Example room: 6m x 7m
A 24000 BTU air conditioning unit is designed for extra-large spaces such as large open-plan living rooms, offices, retail stores, or conference rooms.
BTU to kW Conversion Guide
Another way to compare aircon sizes is using kilowatts (kW). Here is a quick conversion guide:
| BTU/hr | kW (Approx.) |
| 9 000 | 2.64kW |
| 12 000 | 3.52kW |
| 18 000 | 5.28kW |
| 24 000 | 7.03kW |
| 36 000 | 10.55kW |
Other Factors That Affect Aircon Size
While room size is the main factor, there are other things that can influence the ideal aircon size for your space:
- Ceiling height
- Large windows and direct sunlight
- Open-plan layouts
- Number of people using the room
- Heat-generating appliances
- Insulation quality
If your room gets a lot of afternoon sun or has extra high ceilings, you may need a slightly larger unit for optimal cooling.
Still Not Sure What Size Aircon You Need?
If you are still unsure which aircon size is right for your space, the best option is to speak to an expert.
Book a consult with an accredited installer and get professional advice tailored to your home or business. An experienced installer will visit your property, assess your room size and layout, and help you choose the best air conditioner for efficient cooling and energy savings.
At Fourways Online, we make it easy to find the perfect air conditioner for every room. Browse our range of trusted aircon brands online or contact our team for expert assistance.