How Many Square Feet Per Ton Of AC?

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Your AC unit has a capacity for how large an area it can cool down. Have you ever wondered how many square feet an AC can cover per ton unit? Don't worry! We researched this topic for you!

A ton of AC can cover up to 600 square feet of an area. An AC ton is equivalent to 12,000 BTUs (British thermal units), the standard unit for heat transfer.

The square footage an AC can cool down can be found by multiplying the tonnage unit of an AC by 600.

In this article, you'll learn how to calculate AC tonnage. We'll cover the proper computations and even give some typical examples. We will discuss some other relevant matters regarding the tonnages. Keep reading to find out more!

opened condenser unit for indoor air conditioning. How Many Square Feet Per Ton Of AC

How Many Square Feet Per Ton Of AC?

The standard for measuring thermal energy is the British Thermal Unit (BTU). The BTU refers to the necessary amount of heat to raise one pound of water by one degree Fahrenheit.

Air conditioners often list a tonnage. This doesn't refer to how much they weigh, but, rather, how many BTUs they can generate.

For air conditioners, one ton equals 12,000 BTU, which is sufficient for 600 square feet of area. This means that for every square foot, you need 20 BTU.

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Tonnage refers to the capacity of an AC to modify a temperature within an hour. It means that for every hour, a 1-ton AC can cool down an area of 600 square feet. This also means that 12,000 BTU is needed to raise the temperature in a 600-square-foot area.

In simpler terms, you need to install an AC with a 1-ton capacity for every 600 square feet of area. And the thermal energy needed to heat up such an area is 12,000 BTU.

Architect Drawing On Blueprint And Using Calculator

How to calculate AC tonnage

Here we will include some formulae that will help you make these calculations on your own. Remember that the 1 ton to 12,000 BTU conversion is absolute, but conversions to square-footage are just estimates.

Refer to the formulae below:

1. Finding the Coverage Area

To find out how many square feet your AC can cover, divide the ACs BTUs by 20.

Area = BTU ÷ 20

In some cases, the BTU output of your AC might not be readily available. In this case, you can use the tonnage instead. Because a single ton is equivalent to 12,000 BTUs, and 12,000 divided by 20 is 600, you can simply multiply the tonnage by 600, like so:

Area = Tonnage x 600

2. Finding the Tonnage

Should you want to compute what tonnage of AC an area needs, simply refer to the formula below:

Tonnage = Area ÷ 600

If you know the BTU rating for your AC, but not its tonnage, you can calculate the tonnage by dividing the BTU rating by 12,000.

Tonnage = BTU ÷ 12,000

3. Finding the BTU

To find the BTU rating for a unit that you know the tonnage for, simply multiply the tonnage by 12,000.

BTU = Tonnage x 12,000

To find the BTUs you'll need for a specific area, multiply the area in square feet by 20.

BTU = Area x 20

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The Examples

It's good to make realistic examples to better comprehend the given formulae. We've prepared some questions below to show you how to compute them by yourself. See below these examples.

1. How Large Can A 3-ton AC Unit Cover?

Based on the question, the missing variable is the area. Since the BTU is not given, we can use the second formula in finding the area. See solutions below:

Area = Tonnage x 600

= 3 x 600

= 1,800 square feet.

Answer: A 3-ton AC unit can cover up to 1,800 square feet.

2. The Area Measures 400 Square Feet. How Many BTU Should the Area Need?

Given that there's no ton unit indicated, we can use the estimation of 20 BTU equals to a square foot. See computation below:

BTU = Area x 20

= 400 x 20

= 8,000 BTU

Answer: You need 8,000 BTU to cover the area of 400 square feet.

3. What AC Tonnage Do You Need If the Area Is 1,100 Square Feet?

The goal is to find a suitable AC unit with a capacity to cover up the area of 1,100 square feet. Since 600 square feet is equal to 1-ton unit, we can simply divide the area by 600. See solutions below:

Tonnage = Area ÷ 600

= 1,100 ÷ 600

= 1.83-ton unit

Answer: You need and AC with a 1.83-ton unit to cool down an area of 1,100 square feet. You can use an AC unit with capacity ranging from 1.5 to 2 tons, since AC manufacturers don't usually make models for such exact ton unit.

Air conditioner unit outdoors in side yard of a brick home in hot summer season

Why Do We Measure the Tonnage?

It's important to measure the tonnage, or the cooling capacity, of an AC in a specific area. You need to find the right AC for the area. Otherwise, your AC may release too much energy, which may cause your bill to go up.

The AC has a limit on its performance. For instance, an area of 1,000 square feet may be difficult for a 1-ton unit to cover. A 1-ton unit will force itself to adjust the temperature just to fill up the entire area. This will cause the AC to malfunction.

Can You Install Another AC to Meet the Tonnage Requirement?

Let's say there's an AC in an area with a 1-ton capacity. But you just found out that, upon computation, the area needs a 2-ton unit.

The quick answer is yes. You can add another AC to meet the tonnage requirement. This technique is considered safe, as a smaller AC is better at balancing the temperature compared to the oversized one.

However, it's recommended to upgrade to the right size. Two air conditioners running together can affect your bill more than having one proper AC size covering up the entire area.

Big Air Conditioner Hvac Exterior Unit Box

Can You Use an Oversized AC?

You should not use an oversized AC. The air can cool down too fast, which is a bad thing for many reasons. See below for these reasons.

Health Risks

An oversized AC can create air circulation quickly, which is bad for the normal body temperature. It can be risky for your health. You may experience fatigue, headache, or flu-like symptoms due to a sudden temperature change. Keep in mind that our body needs proper and timely adjustments in temperature.

Waste of Energy

It's obvious that an oversized AC will consume too much energy through a forceful release of air temperature. It may cool down the room in no time, but the excess energy will just escape and harm nature.

Electric Overflow

This is the most concerning reason not to use an oversized AC, as it may result in a fire. The bigger the AC is, the more power it demands. Since the AC takes a shorter time to fill up the room, the discharge of energy is faster. Also, electric overflow will cause damage to its motors.

close up photo of turned on indoor unit of a split type air conditioner


How to Make the AC More Efficient?

It's important that the AC performs at its best. We've listed some ways to make your AC more efficient. Remember that you can do all of them together.

Close the Air Exits

By closing the air exits, such as windows and doors, you can insulate the room. The AC will find it easier to fill up the room until it reaches the set temperature. However, you should not lock yourself in a room with AC. Consider going outside often.

Clean the Vents

Cleaning the vents is a practical way of conserving energy. You should clean them at least once a month.

Prepare the following tools for cleaning the vents:

Vacuum Cleaner

Use a vacuum cleaner to suck any dirt or dust off of your AC vents.

See this vacuum cleaner on Amazon.


Open the vent cover with a screwdriver.

See this screwdriver on Amazon.

Cleaning Solution

Use a cleaning solution to get rid of the dirt on the cover.

See this cleaning solution on Amazon.

Scrubbing Brush

You need to scrub the vent with a brush.

See this scrubbing brush on Amazon.


Wear your mask for safer inhalation.

See this mask set on Amazon.


Wear your gloves for hand protection.

See these gloves set on Amazon.

Simply follow these steps to clean the air vents:

  1. Wear a mask and gloves.
  2. Unscrew the vent cover.
  3. Suck off the dirt with a vacuum cleaner.
  4. Brush the vent on the inside.
  5. Wash the cover with the cleaning solution and water, then let it dry before putting it back.

Hands of technician using screwdriver when installing air conditioner in bedroom of customer. How Many Square Feet Per Ton Of AC


In this article, we saw how to calculate the tonnage for your AC and why it's important. We also included other relevant formulae for calculating square footage and BTUs.

Next is that we tackled the proper sizing of the AC and how it affects us. You've learned why you should not use an oversized AC.

Lastly, we provided some ways to make your AC more efficient. Just don't forget to clean the air vents.

You enjoyed this useful article, right? How about visiting our other articles? You should try these:

What Size Breaker For 3 Ton AC?

What Size Line Set For An AC By Ton?

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