How To Determine AC Tonnage From Model Number

Every HVAC appliance you will ever buy will come with a sticker that is full of codes and numbers and letters. Most often, the average consumer can't decipher what all those combinations of numbers and letters mean. But worry not! We've done our research and asked the professionals to help you make sense of them.

To determine the AC tonnage of your airconditioning unit, follow these simple steps:

First, you will have to retrieve the model number of your AC from the information sticker, typically located at the side or the back of the unit.

Second, you will have to determine the BTU rating of your unit from the model number. Most companies include a two or three-digit even number combination that indicates the BTU rating of the unit.

Finally, divide the BTU rating of your unit by 12 and the answer will be the tonnage of your AC.

Determining the tonnage of your AC unit is pretty straightforward. Want to learn more nifty stuff about your AC?  Head on over to the rest of the article to learn more about the importance of knowing the tonnage of your AC and other relevant information about your AC unit.

Air conditioner on wall - How To Determine AC Tonnage From Model Number

What Is AC Tonnage?

Air conditioner unit outdoors in side yard of a brick home in hot summer season. No people.

In the world of HVAC, tonnage has nothing to do with how much your AC weighs. Tonnage is just another classic example of how different fields, use words or terms without any correlation to their actual meaning. Tonnage here describes how much heat from your home the AC can remove in an hour.

The measurement for heat that HVAC people use is the British thermal unit (BTU). A one-ton AC can remove 12,000 BTUs of air per hour, a two-ton AC can remove 24,000 BTUs, and so on. To put it simply, the higher the AC tonnage the more air it can cool.

Why Knowing Your AC Tonnage Is Important

Now you might think that you need to buy the highest tonnage to get maximum cooling power and efficiency. That is not always the case in the world of air conditioning. Sometimes, less is more. Blindly going for the highest available AC tonnage could spell disaster for you and your wallet. Here's why:

  • A small room with an excessively large AC unit can cause your system to cycle often. This will result in more wear and tear for the critical parts and could also result in unnecessary damage.
  • You'll surely spend more money on your electric bill, especially during the hot seasons. A larger AC unit will have a larger motor that requires more electricity to be operational.
  • A larger AC can increase humidity. If humidity problems are already common where you live, you wouldn't want your AC unit to be another addition to this problem.

Additionally, opting to undersize the AC unit less than the one required for your home can also result in some problems and issues. Here are some problems you might encounter:

  • Your home will never feel cold enough. Sometimes this is caused by dirt on the vents or a dirty air filter. But if none of the obvious culprits apply, it might be that your AC unit is too small to effectively cool your home.
  • Your AC never stops running. AC units have sensors that tell them to stop when the desired temperature has been achieved. If your AC is too small, the cooling power won't be able to reach the desired cold temperature and signal the AC unit that the cycle has been completed.

How Do I Select The Right AC Size For My Home?

woman buys a air conditioner

Selecting the correct AC size for your home can give you and your family the best cooling experience, especially on hot summer days. To determine the size of the AC unit you should buy, you first have to calculate the size of your home.

There are two methods you can use to calculate the size of your home. The Area Method or the Volume Method.

Area Method

To get the area, multiply the length and width of the room (should be in feet). Then take the square root of the answer and divide by 10. The result will be the recommended tonnage.

Volume Method

For this method, you multiply the length, width, and height of the room (should be in feet). Then the answer should be divided by 1000 and this will result in the tonnage recommended for the room size.

Alternatively, here's a quick list that shows common measurements of floor areas with their corresponding AC tonnage.

  • 600 sq. ft. = 1 Ton
  • 900 sq. ft. = 1.5 Tons
  • 1,200 sq. ft. = 2 Tons
  • 1,500 sq. ft. = 2.5 Tons
  • 1,800 sq. ft. = 3 Tons
  • 2,100 sq. ft. = 3.5 Tons
  • 2,400 sq. ft. = 4 Tons
  • 2,700 sq. ft. = 4.5 Tons
  • 3,000 sq. ft. = 5 Tons
  • 3,300 sq. ft. = 5.5 Tons
  • 3,600 sq. ft. = 6 Tons

How Is AC Efficiency Measured?

Air conditioner on wall.

An air conditioner's efficiency is measured using the Energy Efficient Ratio or EER. EER is the ratio of the cooling capacity (in BTU per hour) to the power input (in Watts).

An Efficient AC unit will have a higher EER rating. This is what every HVAC manufacturer aims to achieve. It's common for today's top-of-the-line AC unit to have an EER rating of 14.

It is important that before you commit to a specific AC unit, you have to know its EER rating. Why? Because in the long run, energy-efficient AC units will save you more money.

Here are some of the reasons why it's important to know about EER ratings on AC units.

  • A higher EER directly translates to lower energy consumption, which then translates to lower energy bills.
  • They provide a much better cooling experience. High EER AC units often use better parts and technologies to operate. This will produce improved performance and an overall better cooling experience.
  • High EER rating units are much more eco-friendly.

The governing body that promotes and runs this program is the U.S. Environmental Protection Agency. They provide information about the energy consumption and efficiency of most household appliances and devices using standardized methods.

All products that meet their standard will have an Energy Star sticker attached. So the next time you buy an AC unit, make sure to check if it has that coveted Energy Star sticker.

What Are Good AC Unit Brands?

Today's market is saturated with companies that provide their consumers with the latest and greatest when it comes to air conditioning.

You'll find an assortment of products that cater to almost everyone. So if you're in the market for a new AC unit or just someone that wants to upgrade their system, there is surely something out there that will suit your fancy.

American Standard

American Standard has been a staple in the HVAC industry. One of the very first companies to produce air conditioning units, they still are one of the top companies today.

They're known for their reliable products and low maintenance costs. Purchasing a regular unit from them would cost around $3,500 to $6,000 on average, a price which can be considered very competitive in the industry.


Carrier is another company that has been at the forefront when it comes to high-quality air conditioners. Their systems are built with strict quality standards in mind. This ensures that consumers will have a good time with their Carrier systems.

They offer a wide range of selections which ensures that you will find the perfect one for your home's cooling and heating needs. Installing a Carrier AC unit typically costs around $4,500 to $7,000.

If you want a comparison between the two abovementioned HVAC giants, you might want to check out this great post:

American Standard Vs. Carrier: Which To Choose?


Now, this is a crowd favorite. Goodman air conditioning units are known for being cheaper to install and maintain, with average installation prices ranging from $3,000 to $4,500.

The company has a small but relatively solid line-up of AC units. Homeowners often label Goodman as one of the best bang-for-buck brands out there on the HVAC market.

If you want to learn more about Goodman AC units, please check this post out:

How Long Does A Goodman Air Conditioner Last?


Rheem is another HVAC company that is also on the cheaper side but quite dependable. When maintained properly, Rheem AC units can just be as reliable as some of the other higher-priced brands.

Average installation costs for Rheem units can range from $3,000 to $4,000 which is worth considering when you work within a budget.

To know more about Rheem, check out this post we made about their products:

How Much Does A Rheem Air Conditioner Cost

To Wrap It Up

Bag of repairman's work tools, screwdriver on top of an air conditioner unit outside a residential home's back yard. Service industry, working class. No people. Summer.

Knowing the small but relevant information on an AC unit is important as these small pieces of information can have an effect once you own the unit.

These factors can play a role in whether giving you the best cooling experience or the opposite. So if you're planning to purchase a new AC unit or just want to upgrade your system to the latest model. Just remember one important thing, always check the label!

If you found this article insightful, check out these awesome articles about:

How To Properly Air Out A Room

Do Air Conditioners Filter Smoke?


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