How to Calculate Aircon BTU for Your Room

How to Calculate Aircon BTU for Your Room


British Thermal Unit (BTU) is one of the essential things you must consider when you are in the market for a new air conditioner (aircon). Choosing the correct aircon BTU for your room gives you proper comfort and save energy at the same time.


But, how to calculate the appropriate aircon BTU for your room? Discover what aircon BTU is and the rule of thumb in determining the right size here.


What is aircon BTU, and why is it important?



Aircon BTU is a measurement for aircon cooling capacity. It essentially tells you how powerful aircon cooling is. That is why the higher the aircon BTU, the higher its price is.


This begs the question: why should customers choose the right BTU?


It all boils down to efficiency and comfort.


According to National Environment Agency (NEA), bigger than needed BTU is not necessarily better. An aircon with oversized BTU for your indoor space is more expensive, costlier to operate, and cannot dehumidify the room properly. Also, the cooling will make your skin unpleasantly clammy.


On the contrary, inadequate aircon BTU cannot give the cooling and dehumidification you need. Inadequate cooling means longer cooling times. That leads to high electricity bills because you have to turn on your aircon longer than you want.


How is BTU calculated in Singapore?


NEA has a say in how to choose the right aircon BTU for your room.

The general rule of thumb from NEA is:

  1. Total square metres (m2) of the area to be air-conditioned ÷ 5, to get cooling capacity required in kW
  2. Convert the cooling capacity in kW to BTU/hr by multiplying the result in kW by 3412


How to calculate the correct aircon BTU for your room?


You already know how important BTU is when you want to buy a new aircon.


For example, you want to buy an aircon to cool a 15m2 HDB bedroom. The ballpark BTU for that bedroom size is:

  • 15÷5=3
  • 3, the cooling capacity in kW, must be converted to BTU/hr
  • Convert it by multiplying 3 with 3412 = 10,236


Based on the example, you need an aircon with 10,000 BTU to adequately cool a 15m2 HDB bedroom.


The math above is the general assessment to calculate the right aircon BTU. It can help you to determine the right cooling power for your room.


Other factors that affect a BTU size calculation

how to calculate aircon btu

Image source: Samsung


The steps and math from NEA are helpful; however, other factors may require you or your aircon contractor to make adjustments before deciding the best BTU for your room.


Floor to ceiling height


The standard HDB ceiling height is 2.6 metres. You may need additional cooling power for rooms with 3 metres or higher ceiling heights. Please consult with your aircon contractor.




Is the aircon will be for a sunny room like windows are orientated toward the sun? Increase the total BTU by 10%.


Is the room heavily shaded? Homeowners can decrease the total BTU by 10%.


Number of people in a room


Aircon contractors mainly consider a room to be filled with two people regularly. If the room is frequently occupied by more than two persons, you need to add 600 BTU per person.


Heat-generating items


Are you going to put the aircon in the kitchen? That means there will be additional heat sources, like from a stove or fridge. Hence, you must make adjustments, and experts recommend adding 4000 BTU for aircon in the kitchen.


The bottom line in choosing the proper aircon BTU


Calculating the general aircon BTU is pretty straightforward. You can even use many BTU calculators available online.


Once you know the right aircon BTU for your room, reach your go-to aircon installation contractor.


At Purer Fresher Air, the installation of aircon is handled by a team that has been in the business since 2001. We have installed aircon for over 10,000 households across Singapore and are more than happy to help calculate the right BTU for you before you purchase your new aircon.


Give us a call at +65 9830 8224 for aircon servicing, cleaning, and installation. You can also tap the floating WhatsApp button to talk with us or schedule an appointment online.

Get Purer Fresher Air With Us Today!