The required aircon capacity for a medium size room is 12000 BTU. But calculating the required aircon size is not that straightforward. You need to consider factors such as room size, number of people to live in the room, sunlight exposure, appliances used in the room and different other factors while calculating the required aircon capacity. Although it’s a little tricky, let’s calculate the perfect air conditioner size for your home or office in the easiest way.
Why Aircon Size Matters?
Air conditioner size doesn’t refer to how big the unit looks. It means how much cooling power it has. This is measured in aircon capacity in BTU — British Thermal Units.
The higher the BTU, the stronger the cooling. But stronger isn’t always better.
- Too small: Won’t cool the room well. It’ll run all the time and raise your bill.
- Too big: Cools the room too quickly but doesn’t remove humidity. It also wastes energy.
So, choosing the right BTU is vital.
How to Calculate Aircon Required Capacity
Here’s a simple step-by-step guide to calculate how much cooling you need:
Step 1: Measure the room size
Measure the length and width of your room in meters. Multiply them to get the area.
Example:
5m (length) x 4m (width) = 20 square meters.
Step 2: Multiply by 500
For Singapore, a quick rule is:
Room Area (sq m) × 500 = BTU needed.
Example:
20 sq m × 500 = 10,000 BTU.
Step 3: Adjust for extra factors
Consider adjusting the required BTU as per below rule:
- If the room is very sunny, add 10%.
- Add 600 BTU for each extra person (after 2 people).
- If the room is a kitchen, add 4,000 BTU.
Step 4: Round up to the nearest standard BTU
Common BTU sizes for aircons in Singapore are 9,000, 12,000, 18,000, and 24,000.
Hence, always round up if your calculation is close to the next level.
For example, for a 20 sq m room, the required BTU = 20 sq m × 500 = 10,000 BTU. Now, adding 10% extra for a sunny area, we get = 10,000 + (10% of 10,000) = 11,000 BTU.
Rounding it up to the nearest standard BTU, the actual requirement is = 12,000 BTU for 2 people living in the room.
BTU Guide Based on Room Size
Here’s a quick guide to help you match your room size to the right aircon size.
| Room Size (square feet) | Recommended BTU |
| Up to 150 sq ft | 6,000 BTU |
| 150 – 250 sq ft | 9,000 BTU |
| 250 – 350 sq ft | 12,000 BTU |
| 350 – 450 sq ft | 18,000 BTU |
| 450 – 650 sq ft | 24,000 BTU |
For square meters:
| Room Size (square meters) | Recommended BTU |
| Up to 14 sq m | 6,000 BTU |
| 14 – 23 sq m | 9,000 BTU |
| 23 – 32 sq m | 12,000 BTU |
| 32 – 42 sq m | 18,000 BTU |
| 42 – 60 sq m | 24,000 BTU |
Other Factors That Affect Size
Room size isn’t the only thing that matters. Here are other things to think about:
- Sunlight: A very sunny room needs about 10% more cooling.
- People: Add 600 BTU for every extra person after 2 people.
- Appliances: Heat from TVs, computers, and lights can require more cooling.
- Kitchen: Always add 4,000 extra BTU if you’re cooling a kitchen.
- Ceiling height: Higher ceilings mean more air to cool. You might need more BTU.
Consider these factors while calculating the final BTU capacity.
FAQ
What happens if I install an aircon that’s too powerful?
An oversized aircon cools too fast but it doesn’t remove humidity properly. It also wastes electricity.
Can I use one aircon to cool multiple rooms?
Only if you use a multi-split system. For example, a system 3 aircon will cool 3 rooms separately using a single outdoor unit.
How long does an air conditioner last in Singapore?
Normally, 8–10 years with regular maintenance.
How often should I service my aircon?
At least once every 3–6 months. More often if you use it daily.
Is a higher BTU always better?
No. You should match the BTU to your room size. Too high will waste energy.
Should I choose inverter or non-inverter?
Choose aircon that use inverter technology if you want to save on electricity and have quieter cooling.
Final Thoughts
Calculating the right size air conditioner is not difficult. Measure your room, calculate the BTU, adjust for extra factors, and pick an efficient model. If you are still unsure, always ask an expert. This way, you can stay cool and comfortable without overspending.
