What does AC Tonnage Mean?

Defining AC Tonnage

Ever wondered what the term “AC Tonnage” means? Find out in our quick guide and choose the best AC system for your home.

Spend any time around HVAC technicians and you’ll eventually hear terms and phrases that sound mysterious and out of the ordinary. Take “AC tonnage,” for instance. It’s a crucial part of choosing the right AC system for your home, but it seems hard to understand at first glance. Fortunately, we’re here to shine a light on AC tonnage, what it means and how it can help you choose an AC system that’s right for your home.

AC Tonnage: It’s Not About Weight

Forget about weight – AC tonnage means something completely different in the HVAC world. In this case, AC tonnage refers to an AC system’s cooling capacity. Sounds crazy? Let’s look a bit deeper.

Remember, AC systems don’t add cold air, but instead remove heat from your living spaces. AC tonnage basically tells you how much heat your AC system can remove, as measured in British Thermal Units, within an hour’s time. BTUs represent the amount of heat energy needed to raise the temperature of a pound of water at sea level by one degree Fahrenheit.

In the case of a “1-ton” AC system, that means it’s capable of removing 12,000 BTUs of heat energy per hour. Likewise, a 2-ton AC system removes around 24,000 BTUs of heat each hour. Most AC systems are sold in terms of tonnage – 1-ton, 2.5-tons, etc.

The term has its origins in the 19th century, back before the advent of modern refrigeration. Back then, most people still used thick blocks of ice for cooling and refrigeration. In this case, AC tonnage measures how long it takes to completely melt a block of ice in a 24-hour period.

How Much AC Does Your Home Need?

For a quick way to find out how much AC tonnage your home needs, measure your home’s square footage, multiply the result by 25 and then divide that number by 12,000.

Fortunately, your HVAC technician has more accurate ways to determine your home’s AC tonnage needs. A Manual J heat load calculation, for instance, factors in a wide variety of details about your home, including whether it’s accurately insulated, how many heat-producing appliances you have and the number and orientation of the windows in your home.

In the end, AC tonnage makes it easier to know how powerful your new AC system needs to be. Not only that, but you won’t have to draw a blank the next time your HVAC technician mentions “AC tonnage” when discussing your HVAC options.