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How Do I Calculate Air Conditioner for a Room

In the hot and humid climate of India, investing in an Air Conditioner becomes a blessing as it offers the benefits of maintaining humidity levels, cooling comfort, purification of air, and most importantly respite from the heat.

If you are in search of a detailed buying guide on how to calculate the Air Conditioner for your room, this blog is for you.

There is a great alternative to buy an AC and that is: Making an AC at home. Read it now, and save some bucks!

In this blog, we will understand the cooling capacity of an Air Conditioner in a room and choose the best Inverter Technology AC or Non-inverter AC that suits your requirements.

Calculating Room Area and Understanding the AC Cooling Capacity

Before buying an Air Conditioner, apart from looking towards the different AC technology and brands, you need to calculate the size of the room and measure the space to choose the best AC based on the cooling capacity.

Once you calculate the room area, know the cooling capacity of AC required. The cooling capacity of an AC is calculated in British Thermal Units (BTU). In simple terms, the amount of heat converted into cool air by an Air Conditioner in a given time period is known as BTU.

Now, why is it important to understand the BTU chart while selecting the room AC?

If the BTU capacity is high for the given room size, it will fail to maintain the humidity levels making your skin feel clammy and sticky. Whereas, if it’s low then the room will not cool effectively. Hence, selecting the right AC with the standard BTU capacity is foremost.

Note that, 1 ton = 12000 BTUs per hour.

Let’s understand the method to calculate the estimated AC tonnage for a given room area.

Area Method to Calculate AC Tonnage:

Example 1: Length= 12 feet long, Width= 10 feet wide

Area = 12*10 = 120 sq. ft

AC Tonnage = (120/100) = 1.2

Choose an AC of 1.2 Tonnage

Volume Method to Calculate AC Tonnage:

Example 2: Length= 12 feet long, Width= 10 feet wide, Ceiling Height = 24 feet high

Volume= 12*10*24= 2880 cu. feet

AC Tonnage= (2880/1000) = 2.88 ≈ 3

Choose an AC of 3 Tonnage

BTU Calculator

BTU Per Hour and AC Tonnage Chart for a Room Size

Room Area ( Sq.ft)

Cooling Capacity (BTU ) Per Hour

Less than 90 sq. ft

5000 BTU’s

Note: AC Tonnage 0.5-0.8

90-110 sq.ft

12000 BTU’s

Note: AC Tonnage 1

120-150 sq.ft

18000 BTU’s

Note: AC Tonnage 1.5

150-220 sq. ft

24000 BTU’s

Note: Ac Tonnage 2

However, you can use the BTU calculator to gauge the estimated cooling capacity required for a particular room size or a house.  

 Do not miss to consider factors like ceiling height of your room, window size, the average temperature in your location that are responsible for the cooling effects of the Air Conditioner. 

Important Features of Room AC to Consider



Energy Efficiency

It is one of the qualifying factors we look up to before buying any electronic appliance. Here, energy efficiency means the capacity to save on energy consumption and hence the power bills. It is always recommended to buy a 5 stars AC and if not at least 3 stars, to save your pocket on high rates of power tariffs.


Buy the Air Conditioning system that works on an auto-cleaning mode and remove the allergic deposits within the blower.

HVAC Air Filters

Invest in the AC with air filters that inhibit dust particles, pollen, and other contaminants to maintain a Clean AC and quality airflow. It is necessary to enjoy a healthy cooling environment.

Dehumidifier System

The dehumidifier system controls the humidity in the air and allows clean air circulation within the room. It dehumidifies the air in monsoon and prevents it from getting damp.


In the Inverter AC, the compressor works to reach the preset temperature of the thermostat but after that slows down to maintain the cool airflow. This way the inverter AC is heavy-duty and energy-efficient compared to the non-inverter technology.

Living room with AC

Select the Right Air Conditioner for Your Needs

After studying all of these key pointers, selecting the right air conditioner for your room depends on your budget, room area, cooling technology, cooling capacity, and type of air conditioner.  

Essentially there are three different types of air conditioners which are Window AC, Split AC, and Portable AC.  Window AC is composed of a single unit fixed into the window. A Split AC comprises a cooling unit and a compressor unit, one fixed into the room, and the other is installed outside the house. Whereas Portable AC is useful for rented places, a freestanding single unit model able to move from one corner to the other. 


This was a detailed description of how to calculate the perfect AC tonnage for a typical room area and the corresponding BTU output per hour.

We hope this blog has got you sorted to count the right tons of AC for your room or house and you now know which Best Ac in India you need to buy.

Buy Best with BestCheck!

If you have any questions please feel free to write a comment


  1. Rohit Says: on October 06, 2021 at 5:05 pm

    Something mathematical but surely useful and easy to understand. Thanks for the information.

  2. Manvendra Prasad Says: on September 22, 2021 at 4:04 am

    Useful information for someone who is looking to buy a new Air Conditioner.

  3. Rimi Sharma Says: on August 24, 2021 at 7:07 am

    A well designed calculator. Surly helps people like me who are looking to buy an AC but are in a dilemma whether to buy a 1.5 ton or 2 ton AC.

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