While buying an AC, most of us look for many features such as a window or split AC, inverter or non-inverter technology, SEER rating, energy efficiency etc. But the single most important factor that is often ignored is the Size of the AC.
The correct size of an AC is essential to ensure efficient cooling and avoid high electricity consumption. It is directly responsible for the cooling capacity of the AC. But choosing the correct size of AC is a difficult process that requires you to consider multiple factors.
In this article, we will help to do just that, read along to find out the perfect size of an AC for your home.
What is the Size of an AC?
Before, we understand what size of AC is suitable for you. Let us take a look at what and how the size of an AC is determined.
The size of an AC is generally represented in the term BTU or ton or tonnage. The full form of BTU is British Thermal Unit which is a unit for measuring the heat energy. It is described as the amount of heat required to increase the temperature of one pound water by one degree Fahrenheit.
In AC, we use this to measure the amount of heat removed. The higher the Btu, the greater the cooling capacity of the AC will be.
1 ton = 12000 Btu/hr
So, a 1 ton AC will remove 12000 Btu of heat in 1 hour. Similarly, a 2 ton AC will remove 2400 Btu of heat in one hour. This is how we measure the capacity of an AC.
Why is Correct Size of the AC Important
Many people believe that a higher capacity AC automatically ensures efficiency and better cooling. However, this is a misconception. You need to buy an AC that is exactly compatible with your room, otherwise, your AC will be inefficient.
An AC that has a smaller capacity than required will give you inefficient cooling and high power consumption. It will also affect the longevity of the unit. This is because the AC will have to work at the highest capacity at all times to ensure maximum cooling. This will put extra pressure on the unit and the life span of the unit will decrease significantly.
An AC that has a capacity larger than the one required for your room will consume high electricity and hike your power bill. It will also make the room uncomfortably cold. This will also leave the room excessively humid as the dehumidification process will become inefficient.
How to Find the Correct Size
Many brands such as Blue Star, Carrier and others have size calculators on their website to make it easier for you to decide what size your AC should be. You simply need to enter the city you live in, the dimension of the room you want to install the AC in, the dimension of the windows and door of the room and the position of your room. The calculator will automatically calculate the correct size of the AC you need for the room.
But today we are going to give you an approximate size of the AC you need as per the size of your room.
|Room Size||Capacity of AC|
|Up to 100 square feet||0.8 ton|
|From 100 to 150 square feet||1 ton to 1.2 ton|
|150 to 250 square feet||1.5 to 1.8 ton|
|More than 300 square feet||2 ton|
Factors Affecting the Size of the AC:
The size given above is an approximate value. You need to consider some other important factors in order to find the right size of the AC. Following are some of these factors you should keep in mind;
1. Floor Placement:
Along with room size, you need to consider the floor on which your room is placed. Is it the top floor of the house that gets maximum exposure to sun and heat? If it is the top floor then you need to add .2 to .5 tons extra to your AC capacity as this heat will make the room hotter than an average room.
You also need to consider the room placement here. For example, how many walls of the room are exposed to direct sunlight during the day. This is because continuous exposure to sunlight will make the room hotter and will require a higher capacity of AC to cool the room down.
2. Windows and Door Placement:
Along the lines of the above, you also need to consider the number of windows and doors the room has. This is because the windows and doors will create a leak in the insulation of the room and your AC will have to work at a higher capacity to combat the heat.
If you have large windows in your room or a balcony or both, then you need to add .2 to .5 tons to the tonnage of your AC.
3. Weather Conditions:
Weather conditions have a large influence on the capacity of the AC you need to buy. Hot and humid climates require a higher capacity of AC compared to cooler areas. Therefore, If you live in a city where the temperature can go beyond 45 degrees in summers, then you need a higher capacity AC even for a smaller sized room.
4. Population in the Room:
The more the number of people in a room, the larger heat they will emit while breathing out. This might feel like a small thing, but it can add up quickly and make the room hotter. Hence, if the room you are choosing to install the AC generally hosts a large number of people then you will need a higher capacity of AC.
For example, if you are choosing to install the AC in the living room, then you would need to get a higher capacity of AC as this room will host a higher number of people than a bedroom. The living room also generally has more windows and doors which will make it less insulated than a bedroom.
5. Electrical Appliances:
Almost all electrical appliances emit heat energy when in operation. If the room has more electrical appliances then you need a higher capacity of the AC. If you have an open living room that is connected to a modular kitchen then you need a very high capacity AC as there will be many electrical appliances such as refrigerator, TV, gas etc which will make the room very hot.
Even cell phones and laptops emit a significant amount of heat energy that can raise the temperature of the room.
Can an AC Cool a Hall?
This depends on the size of the hall is. In India, generally, a room above the size of 600 square feet is considered as a hall. A single AC can cool the hall if the AC is of the largest capacity ( 2 or 3 tons) and the hall has perfect insulation. However, the time taken to cool down the entire hall will be significantly greater than an average room.
Another thing that you need to consider is the population of the hall. If the hall is meant for large gatherings, then a single AC unit even with the highest capacity will not be enough to cool down the hall. But if the hall has a sparse population then a single unit might be enough. This all depends on how large the hall is.
The room size will definitely be the largest factor while determining the size of an AC but additional factors listed above should also be considered. If you are using an AC size calculator then you don’t need to consider many of these as the calculator already will do it for you. Some companies even provide consultancy services before purchasing where you can talk to a professional who will help you figure out the perfect size of AC for your room.