What Is Air Conditioning Tonnage and Why You Need to Know


Purchasing an air conditioner is something you probably don’t do very often. So most people aren’t familiar with some of the common terms regarding air conditioners. One of the most important things you need to know before you buy a new air conditioner is the tonnage—what is air conditioning tonnage and how much you will need for your home.

What Is Air Conditioning Tonnage?

The term air conditioning tonnage is an HVAC term used for rating AC units. The common perception is that this term relates to the weight of the AC but it doesn’t.

A ton in the HVAC industry is a field term used to describe how much heat any given AC unit can remove from a home in one hour. And the measurement for heat is BTUs, which is a term you’ve probably heard of. This abbreviation stands for British thermal units.

How Much Air Can a One Ton AC Unit Move Per Hour?

A one-ton AC unit can remove 12,000 BTUs of air per hour. A four-ton ac unit can move 48,000 BTUs per hour and so on. Therefore, the more tonnage an air conditioning unit has, the more air it can cool per hour. But that doesn’t necessarily mean more is better—more about that in a moment.

How Much AC Tonnage Will I Need for My Home?

Most homes, depending on varying factors such as ceiling height, windows, and airflow, will require a ton of air conditioning for every 400-1,000 square feet.

Residential AC units range from 18-60, then you divide that number by 12 (this number refers to the 12,000 BTUs per hour or one ton of cooling capacity) to calculate an AC unit’s tonnage. Here’s an overview of the tonnages.

  • 18 = a 1.5-ton unit
  • 24 = a 2-ton unit
  • 30 = a 2.5-ton unit
  • 36 = a 3-ton unit
  • 42 = a 3.5-ton unit
  • 48 = a 4-ton unit
  • 60 = a 5-ton unit

Additionally, if you want to save money, be sure to get an AC unit that is EnergyStar certified. These are the most energy-efficient AC units you can buy.

If I Put a Larger AC Unit on My Home Than It’s Rated for, Will It Cool Better?

Yes and no, BUT… you definitely don’t want to do that. Here are several problems that are a result of using an AC unit that has a higher tonnage than your home requires.

  • The inside temperatures of your home will feel uncomfortable.
  • You might experience hot and cold spots throughout your home.
  • A higher tonnage could result in mold growth on the walls and ceilings.
  • A larger unit will cost more upfront.
  • A larger unit will increase your monthly utility bill.
  • Your unit will experience more wear and tear due to short cycling, which will shorten its life expectancy.
  • Short cycling results in higher humidity levels and poor air quality in your home.

As a general rule, you can safely and without causing any of the above issues, install an AC unit that is a ½ ton larger than what your home size is rated for, but don’t go any higher than that.

What’s Next?

If you are looking for a new air conditioner or want your current air conditioner inspected and assessed, we can help. Please Contact A/C Warehouse today. We have offices in Sarasota, Bradenton, Tampa, and the surrounding areas. We look forward to hearing from you!

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