What Is Aircon BTU (and How To Use It To Choose an Aircon For A Specific Room)

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When it comes to selecting an aircon for your room or office, one of the things you usually consider first is the brand of the aircon company.

However, the size of an aircon (in terms of BTUs) and the corresponding size of the room where you want to install the aircon is just as important as the brand you are buying.

So what exactly is an aircon BTU? How do you use it for calculating whether it is appropriate for a particular room? What are the pros and cons of having a properly sized air-conditioning in any place? All these questions will be answered in the upcoming sections.

What Is An Aircon BTU?

All types of air-conditioners, whether window or split-units, come with a BTU rating. For most of the first-timers, the first question they’ll ask is: what is a BTU in an aircon?

BTU is short for British Thermal Unit, which is a unit showing the cooling capacity of an air conditioner. It is a unit for power used in aircon terminology and plays an essential role in selecting the right size of AC for a particular location.

Simply put, one watt equals to 3.41214 BTUs.

Each aircon has a specific cooling capacity which is evident through its BTU. Depending on the per square foot area of the room, you can select an aircon with a specific BTU which will not be small nor too big. This is especially useful when you are looking to install an aircon.

An aircon which is just about the right size for a particular room will not only cool the room effectively but will lower energy bills and maintenance overheads.

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Helpful read: Aircon maintenance and repair cost in Singapore

Pros And Cons of a Properly Sized Aircon

Having a properly-sized air-conditioning for a particular room is one of the most essential aspects when you are looking to install a new unit. Below, we have listed a few important pros and cons of having a properly-sized aircon for a room:

  • A common misbelief is that for a small room, a larger BTU (or capacity) will be better. However, this is not the case. The larger aircon will not only cost you more but is also very inefficient. A larger air-conditioning unit may be more cooling at the start, but it will not run long enough to be able to draw moisture and humidity from the room. As a result, the initial feeling of cold air will soon falter as you will feel no difference in moisture.
  • Similarly, having a smaller BTU unit in a large room will not adequately cool the room. The aircon compressor will continue to work for longer durations to achieve the desired temperature. This will make it overheat, which can cause it to become faulty or shut down completely. Because the compressor continues to work for longer durations, this leads to an increase in the energy bills as well. The room, still, is not able to cool properly because the capacity of the unit does not allow it to properly cool that big a room no matter how hard it works.
  • The right-size aircon will effectively be able to cool the room while the compressor still has enough opportunity to rest in between.
  • An air-conditioner which is the right size for a room according to its BTU will also be able to remove humidity and moisture from the room. It will be able to run at its optimal capacity for longer durations and require less maintenance. The chance of its components getting faulty will also be lesser in comparison to an aircon which is not the right size for a particular room.

Helpful read: Why is my aircon not cold?

Choosing the Right Cooling Capacity of Your Air-Conditioner for a Particular Room

Choosing the right aircon for a particular room is as important as the company or brand you wish to choose.

An aircon is not only responsible for cooling but also decreasing the humidity of a particular room. Both of these functions are extremely important for the hot and humid weather of Singapore.

This begs the question: How do I calculate an air conditioner for my room?

To assess whether a particular aircon is appropriate for a room or not, you can use the following aircon BTU calculations if you are living in Singapore:

  • The first step in this calculation process is to calculate the area of the room. Measure the length and width of the room in the unit of the foot. Multiply the length with width to come up with the area in square feet. This is possible in the case of a square or rectangular room. If your room is of any other shape, it is a good idea to call an expert who knows how to calculate the square foot area of the room.
  • Once the area has been calculated, multiply it with 25 BTU to determine the minimum cooling capacity required for this size of a room.
  • It would be best if you chose an aircon whose BTU is a bit more the resultant value you got in the above step.
  • For example, if you have a room whose length is 15 feet and its width is also 15 feet. The area of this room will be 15 x 15 = 225 sq ft. Now multiply it with 25, this comes out to be 225 x 25 = 5625 BTU. Therefore, for this size of a room, an aircon with a 6000 BTU capacity will work the most efficiently in cooling as well as decreasing humidity.

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Aircon BTU and room size

  • What size room will an aircon with 5000 BTU cool?

The most common BTU of an average aircon ranges from 5000 BTU to 12,000 BTU. A 5000 BTU air conditioner is approximately the average cooling capacity of a budget aircon and

  • What size room will an aircon with 9000 BTU cool?

An aircon unit with 9000 BTU can cool a space between 35 metres square to 40 metres square, which is approximately 400 to 450 square feet.

  • What size room will an aircon with 12 000 BTU cool?

The higher end of the cooling capacity of an average aircon, a 12,000 BTU aircon can cool a room or space that is between 45 to 50 metres square, which is around 500 square feet to 550 square feet.

However, do note that the actual performance may vary based on the type of aircon used. This is because manufacturers will give their own perceived ratings on how much space their aircon unit can potentially cool and there may be variations on the ratings.

Additionally, rooms with higher ceilings or more unique floor plans will probably need more cooling power due to the layout of the room. In situations like this, it is recommended that you increase your BTU total by 10% for the most ideal estimate of the required aircon size.

Making Adjustments in BTU Calculations

The steps and calculations mentioned above are the generalized BTU calculation which should be the basis when you are determining the required cooling capacity of a room. However, there are certain factors which could affect your BTU calculation.

Depending on these factors, you should make a few adjustments in the calculation while choosing an air-conditioner. These are discussed below:

  • If the room for which you are choosing is heavily shaded and its roof insulated, it is a good idea to decrease the BTU calculation by 10%-20%.
  • If the room remains in direct sun for the most part of the day or if it contains large windows which would comprise the insulation of the room, then it is a good idea to increase the BTU calculation by 10%-20%.
  • In the case that the air-conditioning unit is to be installed in the kitchen, experts recommend increasing the BTU calculations by 4000 units.
  • If the room is to house a lot of people, then roughly 500-600 BTUs should be added in the BTU calculation for each person.

This guide describes the importance of BTUs in calculating the required cooling capacity for a particular room. It is usually a straightforward process which you can do easily by yourself.

However, hiring professionals to do the exact BTU calculation during installation for you ensures that you select the right unit for your room which can cool it efficiently.

In return, the aircon will work at its optimum capacity for longer durations while still conserving the energy bills. When it comes to working at optimum capacity, you may want to consider regularly servicing to ensure the air-conditioning unit can work well over the long haul.

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