If this is your first time buying Aircon. You will be bombarded with foreign terms such as : 9000 BTU + 180000 BTU. As confused as you might be. BTU stands for British thermal unit, which is the amount of energy needed to raise one pound of water by one degree Farenheit. If you have an Aircon inside your room, if you open the door, chances are, your whole house won’t get cooled. Why? This is because you have insufficient BTU to cool the whole house. Now you must be thinking, I want to cool my room, why the hell do I care about heating my room right? If you translate this term to Air-conditioning, it refers to the amount of energy it generates per hour to remove excess heat. Hence in short, the bigger the room, the more BTU you need to cool the area.
What are some of the other factors that affect btu?
As you have learned in science class back in Primary school. Heat travels from hot to cold objects. Hence, a room with other heat source would require the Aircon to work even harder. Which means, for a room that is crowded, you will require a bigger btu level. If it is a commercial property with a lot of printing equipment, the BTU level much more than the usual ones. Other than heat sources from the inside. You will have to take note of the potential heat source from outside. Which means if you have a window facing the east or west direction. That room might need more btu than normally required. Because the sunlight will heat up the room during certain times of the day, depending on where your window is facing. Even if you install curtains, the sun could still heat up the wall, causing your room to be stuffy and hot. This is especially so for units on the highest level, it will be hotter than usual as the sun can shine on your ceiling directly.e
Is too much BTU a good thing then?
Using the analogy as described earlier. Your Aircon in the room won’t cool the whole house because it doesn’t have enough btu. Can your Aircon in the living room be used to cool your room then? Answer is : YES it can. But is it good for you? It definitely isn’t. BTU that is higher than required will cause it to cool too quicly, cycle off, then cycle back on in order to maintain your cooling temperate. This can cause the Aircon compressor to overwork quickly, resulting and more wear and tear. It will definitely increase your electrical bills as well, even if you are using an inverter Aircon. Nonetheless, as mentioned earlier, if you room has other heat source, you might require a bigger btu.
How do I calculate the BTU that I need then?
For hdb units, this is pretty straightforward. For normal rooms, you generally only require 6500 btu, and 9000 btu for master bedroom. As for a 3 room flat, your living room only needs 12000 btu. 18000 btu for 4 room flat’s living room and 21000-24000 for 5 room flats. However this is just a general guide, there could be exceptions. Some of the 4 room flat at tampines Area have an enormous living room size. You will have to take into account of that based on your floor plan. Therefore it will be safer if you do your own Aircon btu calculation as well. Outline below are 2 methods you can refer to.
To calculate the btu you require, simply multiply the size of your room (in square feet) by around 50-60. You will get the BTU you need.
If you have been measuring your house based on square meter. You can simply take that area and divide by 5. However, the cooling capacity that you will get is in terms of KILOWATT (KW). To convert kilowatt into BTU, multiply the result by 3412.
The method is referenced from energy efficient Singapore website :
However, as described in earlier paragraphs. You will have to take note of the internal and external heat source generated from your room. Other than heat source, you will also have to take into account of height.
Previously we only calculate your required btu base on square feet. So for warehouse or places with high ceiling, you will have to get higher btu too.
Will my room be cooled if my aircon btu calculation is insufficient?
You will still feel a sense of cool breeze in your room. And depending on the time of the day, it could still be cold. However, on very hot days, this feeling of coolness will be severely affected. In addition, it’s not just a matter of whether you room will get cooled. If your Aircon BTU is insufficient. It will cause the compressor to keep running, as the thermistor will indicate that it’s not sufficiently cooled yet. This will cause huge wastages in your electricity consumption. Hence, it will be better if you err on the higher side in terms of aircon btu calculation.
What else do I need to take note of other than BTU?
Look at the picture below. To cool this area, around 36000 btu is required. The owner has decided to install 2 wall mount air-con units. One 24,000 btu Mitsubishi single split at one end of the war and one 12,000 btu Panasonic single split at the other end. This will not result in efficient cooling of the room as the air flow will not be balance. The side of the room with 12000 btu of Aircon will be overworked, resulting in higher electricity and more wear and tear of the unit.
To overcome this, the owner can install a 36,000 btu ceiling cassette unit in the middle. Or install 18,000 btu single split unit at each end of the room.
It is very expensive to install an Air-conditioner, especially at commercial spaces. And if it doesn’t fulfil your cooling requirements due to insufficient Aircon Btu calculation. You might have to change the entire Air-conditioning system. Hence, it is better to get this right, right from the start. You will have to factor in your crowd level, direction of the sun, internal heat sources and the ceiling height. If you are still unsure of the btu that you required for your place, you might wanna hit us up at 91775500. We will be more than glad to be of your assistance in Aircon related enquiries