How To Easily Determine AC Tonnage From Model Number

When replacing or buying an AC, tonnage is a crucial component to consider.

However, most homeowners blindly trust the salesman if they can’t identify their AC tonnage. Knowing this characteristic is vital for many reasons, such as adequately cooling your space, replacing your existing unit, etc.

Want to know how to determine AC tonnage from the model number? Then this guide is for you!

How To Tell The Tonnage Of Air Conditioner Unit?

Figuring out what your AC tonnage is, is pretty simple. First, walk outside your house and read the rating plate located on the condenser unit.

Mostly, HVAC manufacturers don’t show real tonnage; instead, they list “British Thermal Units (BTUs).” It shows the SEER rating (seasonal energy-efficiency ratio) or how well a system can cool your space.

Many air conditioning systems in America range between 5000-20000 BTUs. How many BTUs you need varies based on the place you live and your home’s square footage.

Nevertheless, once you find BTUs on a label, divide it by 12000. This way, you’ll get your right AC tonnage. For instance, if your AC unit is 24000 BTUs, you’ve got a 2-ton air conditioner.

Note: most manufacturers hide the BTU or tonnage information in the model numbers. So, locate the even two-digit figure between 12 and 60. In addition, you may see a three-digit figure beginning with “0”. If you see these numbers, it means you’ve got the BTUs.

Related Article How Many BTU in a Ton?

Carrier Central AC Being Positioned

Determining The AC Tonnage From Model Number

Want to know how much tonnage your air conditioner is? Look no further than the unit itself.

The outside condensing unit of your AC system has a rating plate mounted on the top side. Among other things, it includes a serial number and model number placed on top of a label. The unit’s model number, denoted by (M/N), is where homeowners can find their AC size.

Although not all AC manufacturers do it, many provide customers with 2-3 digits, indicating how many BTUs/hour your unit can cool your house.

If the M/N on your system highlights tonnage, you won’t require any calculation. However, if it doesn’t, here’s how to determine the AC tonnage from the model number:

  • When you find the M/N number, locate its second set, digits after the dash. The number signifies BTUs per hour of your system. For instance, 060 equals 60000 BTUs
  • Divide BTUh on the rating plate by 12000 (1 ton). The result will be the tonnage of your AC system.

Consider the example:

Let’s say you’ve 60000 BTUs. Place it in the equation, and you’ll get your AC tonnage:

AC tonnage = BTU / 12000

AC tonnage = 60000/12000 = 5 tons

What Is The AC Tonnage & Why It Is Important?

Most homeowners believe that AC tonnage refers to the air conditioning system’s weight. However, that isn’t true.

Tonnage or ton can help you determine your air conditioner’s cooling capacity. It tells you how much heat your AC system can remove effectively from the house in an hour.

It’s measured in British Thermal Units, which refers to the heat required to raise one-pound water temperature by 1°F.

A one-ton AC can remove approximately 12000-BTUs of air every hour. In other words, it means that such systems can remove heat generated by 12000 “birthday candles” in about an hour.

A three-ton system can move 36000-BTUs while a four-tonnage unit can remove 48000-BTUs easily, showing more AC tonnage means more cool air.

Most US households will require a one-tonnage AC system for every 500 to 1100 square feet based on airflow, windows, and ceiling heights.

Higher AC tonnage means increased power costs as these ACs work harder and longer. Therefore, buying the right-size AC is crucial.

When purchasing a new AC, choose Energy Star certified units as they’re more energy-efficient. Avoid large systems at all costs. Here’s why:

  • Selecting the wrong AC unit size leads to more wear out, resulting in additional repairs and early replacement
  • Short cycling keeps dehumidification, leaving you with cool but damp interiors. You may turn down the temperature slightly to counter this, raising energy usage.
  • Not only are higher tonnage AC systems expensive, but they’re also costly to run. Hence, it’s a waste if your house can take smaller systems.

How Much AC Tonnage Do I Need?

When selecting a new AC system, you’ll have to measure the tonnage your device needs to cool your property adequately. Luckily, you can do this through a simple calculation.

Consider the argument:

According to the “Department of Energy,” air conditioners typically need 20-BTUs for every square foot of the house.

First, you’ve to convert BTUs to a ton. 12000-BTUs equals 1-tonnage. It means you’ll require 0.0016 tonnage per sq ft, on average. Use this simple AC ton equation to measure how much tonnage you need for your space.

Let’s assume you’ve to cool a 600 sq ft of space. Here’s how much AC tonnage is enough:

AC capacity (ton) = (insert living space sq ft) x (0.0016)

AC capacity = 600 x 0.0016 = 0.96

Though the above equation will provide you with an estimation, it’s crucial to remember that several other factors can impact your AC tonnage needs, such as:

Split Air Conditioner on House Roof
Home’s Current Insulation

Homes with excellent insulation hold cool air more efficiently. They need less tonnage for cooling.

Homes’ Current Landscape

Households having big trees will remain cooler than wide-open spaces, requiring fewer tons.

Home’s Architecture

Typically, cooling a second or third story is most difficult. Conversely, ranch-style homes can efficiently be cooled down. Nevertheless, fewer floors mean less tonnage required to cool the space.

People Also Ask (FAQ)

Here are frequently asked questions on air conditioner tonnage.

Can I replace a 3 ton ac with a 4 ton or 5 ton AC unit?

No, you can’t. Proper size is the key. There’s no good reason to place a 4 or 5 ton AC unit when you can utilize a 3-ton system. Due to the unloading scroll system, the low-stage isn’t less than the total capacity.

How much is a 3 ton AC unit cost?

On average, the 3-ton AC unit will cost you anywhere around $2,890 to $3,280. However, many factors affect your AC costs, such as SEER rating, square footage, brand, and more.

What’s the price difference between a 1 ton and 5 ton AC?

A 1-ton AC unit has 12000-BTUs, while a 5-ton offers 60000 BTUs. It means a 5-ton AC unit has more power and can cool your space within a short period. As their features vary, so does the price. The price difference between a 1-ton and 5-ton AC is $2190.

Do all central AC brands follow a similar formula with model numbers?

While brands might have a few ‘minor’ differences, the fact is you’ll see equal performance throughout the board for units of similar size from various manufacturers.


To determine AC tonnage from the model number is a breeze. First, view the rating plate set up on your unit’s condenser. Next, look for the model number or M/N box on the label. You’ll see BTUs after 5-6 characters.

Simply divide it by 12000, and you’ll have your AC tonnage.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.