Summer is around the corner, and it can get scorching here in India. There’s ample time for you to put on the thinking hat and decide on the ideal air conditioner capacity as per the room size. Getting the right AC capacity can work wonders as that might save you from numerous issues like low cooling or a damp feeling.
Having a smaller ton AC can result in unsatisfied cooling, while a bigger AC can provide the required cooling, but would mostly fail in removing humidity from the air.
To help you out of this mess, I will show how you can calculate the AC capacity of a room in the article.
AC room size calculation: how to choose the right capacity?

A little bit of mathematics will be required to choose the right capacity of AC according to your room size. First of all, find the area of your room in square feet and simply divide it by 600. Add 0.5 tons or more to your answer as an average since there might be more than two people at times.
In terms of calculation for a room size of 100 square feet: 100/600 = 0.166 tons + 0.5 = 0.66 tons (roughly a 0.8 ton AC)
It shouldn’t be much of a problem in selecting the right size of the air conditioner when your basics are right.
AC room size chart according to capacity
AC CAPACITY (TON) | ROOM SIZE (SQUARE FEET) | EXAMPLE |
---|---|---|
1 ton | Up to 150 sq ft | Lloyd 1.0 Ton 3 Star Inverter Split AC |
1.2 ton | 150 – 170 sq. ft | Blue Star 1.2 Ton 4 in 1 Cooling Inverter AC |
1.5 ton | Up to 250 sq ft | Whirlpool 1.5 Ton Flexicool Inverter Split AC |
2 ton | Up to 400 sq ft | |
2.5 ton | Up to 1200 sq ft |
If I take the example of a 1200 square foot room size, you will require 1200/600 = 2 + .5 = 2.5 Ton air conditioner. Selecting the right capacity is the ultimate goal as that would save you from unnecessary costs and things like a clammy feel or low cooling in the room.
Other factors that determine the AC capacity and room size

Several factors determine the AC capacity and the room size too. Here they are –
1. Windows/doors
Keeping your window covered via curtains or shutters can keep the heat out during the summer season, leading to less work for your air conditioner. Similarly, you can opt for a lower AC capacity by keeping the doors closed most of the time.
2. Ceiling
Rooms with standard ceiling height have an ample amount of cool air circulating within the room. This might not be the case for rooms with higher ceiling height as they would require more volume of air that needs to be cool and a higher capacity of the air conditioner.
3. Number of persons
A person on average releases 100 W of heat while at rest. This will double, triple, or more depending upon the number of occupants in a room. More people in a room will require maybe a 1.5 ton instead of 1 ton as an example.
4. Humidity
It has adverse effects on cooling, which results in cancelling the actual cooling power within a room.
5. Other appliances in the room
If there are a handful of them in a room in the form of a refrigerator, television, or washing machine; it will affect the AC performance.
6. Direct sunlight
Exposure of it in your room can result in improper cooling. The sun rays falling in the room will make the air conditioner feel warmer than the actual temperature. Your AC will end up running more than what is required.
Choosing wrong AC capacity as per the room size
Some of the issues you might encounter –
1. Improper cooling
A smaller air conditioner will find it difficult to maintain to keep it at a comfortable cooling temperature. While a bigger unit might cool instantly but might struggle to remove humidity.
2. Break down
Larger air conditioners will be turning on and off at regular intervals (short cycling). Resulting in wear and tear, eventually causing a breakdown. Similarly, smaller ones would be running constantly until they drain out.
3. Expensive additional costs
With constant breakdowns and improper cooling, the repairing costs and electricity bills are going to touch the sky.
FAQs about AC capacity and room size
What is the room size for 1 ton AC?
120-150 square feet should be apt. room size for a 1 ton AC.
Is 1.5-ton AC enough for 400 square feet?
No. A 1.5-ton AC can manage up to 250 sq ft room area. 2-ton AC or above is recommended.
Which AC size is best for 250 sq ft room?
A 1.5-ton AC should be good enough for room size of 250 square feet.
What size AC do I need for 300 square feet?
You can go for a 2-ton air conditioner for a room size of 300 square feet.
How much AC ton is needed for a 10×10 room?
A 100 square feet room (10 ft length & width) will require a 0.8 ton AC.
In conclusion
Buying the ideal size air conditioner is imperative in many ways. You do not want to be hanging in regret after the purchase, with bizarre after-effects. Whether I talk about a 1 ton or 1.5 ton AC, minimal research is required for you to not lose sleep over a bad decision.
You can find the room size chart above for particular air conditioner capacity which will be of help.
Anyway! Did you buy the right AC size?