How to Calculate the HVAC Tonnage Needed in Your Home

Calculating the ideal HVAC tonnage for your home is essential to optimizing comfort, improving energy efficiency, and reducing unnecessary wear and tear on your home’s cooling system. Whether you’re looking to replace an existing central air conditioner or heat pump system or wondering if your unit is up to snuff, a little math goes a long way.

Read on to learn how to determine the tonnage of your HVAC unit, explain the formula, and explain why getting the numbers right is so important.

What Is Tonnage in HVAC?

Tonnage is the standard measurement of an air conditioner’s ability to remove heat. It’s worth noting that tonnage has nothing to do with the weight of the unit itself, which is a common (and understandable!) misconception.

One ton of cooling capacity equals 12,000 British Thermal Units (BTUs) of heat per hour.

Air conditioners and heat pumps don’t actually produce cool air; they remove heat and humidity from the indoor air (and distribute it outdoors). An increase in tonnage represents an increase in cooling capacity, allowing the AC or heat pump to remove heat from a larger area.

In most cases, tonnage is primarily used to calculate air conditioning capacity.

Read more: Why Your AC Is Making Noise

How to Determine the Tonnage of an Air Conditioner or Heat Pump

When it’s time to upgrade or replace your existing AC unit, double check you’re getting the right size. With a little luck, you may not have to test your multiplication skills. There are two ways to determine the exact tonnage of your existing AC unit or heat pump—but manufacturers don’t always make it easy.

1. Check the label.

Examine the outdoor unit for a sticker with model information. Some manufacturers include the tonnage, BTU rating, and model number on this easily accessible panel. Even if the tonnage isn’t clearly listed, there may be a clue in the model number. Look for a two-digit, even number between 18 and 60. This is the BTU rating in thousands.

That makes the math much easier! Divide the number by twelve (remember, one ton equals 12,000 BTUs), and you’ll have the tonnage. Here’s an example calculation if the two-digit number on your air conditioner or heat pump is 36:

›            Two-digit number / 12 = Tonnage

›            36 / 12 = 3-ton air conditioner or heat pump

2. Call the pros.

Unfortunately, not all manufacturers include this information on the unit itself. If it isn’t printed on the label or included in the owner’s manual, try searching the manufacturer’s website using the unit’s model number. You can always contact your local One Hour Heating & Air Conditioning for an expert inspection and advice on how to size an HVAC system.

Additional Factors to Consider

HVAC tonnage is just one of several factors used by professionals to determine the ideal size of your home’s air conditioner or heat pump.

Our technicians consider other important information, including:

1. Square footage

Your home’s square footage is another determining factor in AC tonnage. The larger the home. the more cooling capacity required. While there are several broad formulas used to determine how square footage impacts air conditioner size, the factors below make those calculations a bit more complicated.

2. Climate

Local climate also plays a factor in AC or heat pump selection. Homes in hot climates require ACs and heat pumps with more cooling capacity than homes in mild or cold regions. Our technicians always consider local climate variability when sizing a new air conditioner or heat pump.

3. Insulation

A well-insulated home keeps hot, humid air out more efficiently than a poorly insulated one. This lightens your cooling system’s workload and helps lower your monthly energy bill. It also potentially reduces the size of AC or heat pump you would need to adequately and efficiently cool your home.

Other Factors

It’s important to account for other variables, such as clean and well-maintained ductwork, the number of occupants, and the amount of direct sunlight that enters the home. These variables impact your home’s cooling requirements and the cooling capacity it needs.

Dial in on Your AC Tonnage with One Hour Heating & Air Conditioning

Ready for a new air conditioner or heat pump but not sure what size you need? Our friendly technicians take the guesswork out of sizing your AC unit. Leave the math to our trained HVAC professionals! We’ll measure your home’s square footage, evaluate all the factors influencing your cooling needs, and make expert recommendations to make choosing your next cooling system easy.

Find the One Hour Heating & Air Conditioning location nearest you or call (844) 839-5601 today to schedule an appointment! We’re Always on Time … Or You Don’t Pay a Dime!®.