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How to Select An Air Conditioner Correctly

How to Select An Air Conditioner Correctly

Selecting your air conditioner requires you to know some basic calculations, the right Air conditioner will cool your room efficiently and also will reduce your electricity consumption.

So, in short, you can save money and reduce carbon emissions. Selecting a unit too small will be too underpowered to cool your room. On the other hand, picking an oversized unit will cool the room quickly, but will inefficiently cycle on and off costing you extra money.

All air conditioners lower the room temperature and remove humidity, An overpowered unit if installed in a small room, will cool the room extremely fast. As a result, will run less often leaving more humidity in the air and in course of time your room will become muggy and moist.

The first step in choosing a room air conditioner is measuring your space to calculate square feet area. Once you have this data we can decide on how powerful of a unit we need to go after. The formula used to calculate the area of a typical square /rectangular / triangle is going to be the formula used for most rooms. i.e,

L x B = Area  or L x B x ½ = Area.

Once you have calculated the area of your room please use the BTU chart below for selecting you Air conditioner.

The Area to be Cooled
(Square Feet)

Capacity Needed
(BTU's per Hour)

100 to 150


150 to 250


250 to 300


300 to 350


350 to 400


400 to 450


450 to 550


550 to 700


700 to 1000


1000 to 1200


 To finalize your results you should also consider the following.

  • Ceiling height (above chart is for rooms with 8 feet height)

  • The amount of sunlight entering your room - if it's sunny/shady during the day need to increase BTU by 10% reduce by 10%.

  • If more than 2 people will occupy your room or space regularly, you should add an additional 600 BTU's of cooling power for each person.

  • If you are installing your AC in a kitchen, increase the BTU level by 4,000

With the proper measurements and calculations, you will be able to determine the area of your room and make a wise choice for your next room AC.


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