How Many Amps Does a 1-5 Ton Central AC Unit Use?

Your central air conditioner or heat pump uses 3 to 21 amps based on its size and efficiency.

A 3 ton AC in the SEER range from 14 to 24 SEER will use 7.5 to 12.3 amps. Our Central Air Conditioner Amps Calculator below is simple to use and gives you a precise answer to the question – How many amps does a central AC use?

There’s a quick Table below that does the calculation for you, to some extent. It gives amp ranges for 1 to 5 ton AC units with efficiency ratings of 14, the current minimum, to 25, just about the current maximum.

Central Air Conditioner Amp Draw Calculator

There’s little to explain on this central AC amps calculator, but we’ll walk through it below the calculator. Go ahead and give it a try, and if something doesn’t make sense, check out the descriptions below.

Central AC Unit Amp Draw Calculator

Here’s a quick example of how to use the calculator. Again, instructions are below.

Example: How many amps does a 2 ton air conditioner use?

Answer: Type “2” in the Capacity Box. Type the Efficiency in that SEER box and the voltage in the Volt (V) box. Your answer will be calculated.

A 2 ton 16 SEER AC draws 8.24 amps. A 2 ton 20 SEER AC draws only 6.59 amps while an inefficient 8 SEER AC uses 16.48 amps.

Step 1: Air Conditioner Capacity in Tons

Central air conditioners continue to be listed in tons. One ton equals 12,000 BTU.

Enter the number of tons in the first box.

Amps per ton: If you work through the range of options, you’ll see that air conditioner amps per ton are about 4 amps for a 16 SEER unit. Air conditioner amps per ton rises when efficiency is lower; it goes down when efficiency increases.

If you know the capacity in tons for your AC or heat pump, you can skip down to step 2.

Where do I find AC tons? How many tons is my AC?

There are two easy places to find how many tons your AC is.

1). Your Owner’s Manual should contain a page or insert that has the specifics of your condensing unit – either your air conditioner or heat pump. The information might be handwritten or typed. It will include Model Number, Serial Number and other information.

The number of tons might be written plainly. Options for heat pumps and central air conditioner sizes are: 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 and 5.0 tons.

If written in BTUs, divide the number by 12,000, since 1 ton = 12,000 BTU. For example, if the sheet lists the unit as 36,000 BTU, then divide the number by 12,000 to get 3 tons.

2). On the label on the side or back of the AC or heat pump condensing unit. Do the math explained above, if needed.

Step 2: Efficiency – SEER

Central AC and heat pump cooling efficiency is rated in SEER – seasonal energy efficiency ratio.

Enter your AC or heat pump efficiency. It will be between 8 and about 24.

It can be found in the same locations the capacity in tons is found – on the unit or in literature given you when it was installed. You can also search the brand and model number to find its SEER rating.

Step 3: Volt (V)

Once again, this information is found in the literature or on the label on the outside of the condensing unit jacket. Or you can search it online.

Most central air conditioners and heat pumps are 230 volts, though they can be run on 208 volts, which will increase the amps it draws by about 10%.

Enter the voltage of your AC or heat pump.

Pro Tip: You might have a 240V breaker and line feeding power to the condensing unit. But the unit will only use its rated voltage – 230V or 208V.


As you enter the information above, the Result will automatically change.

When all the information is correct, view your Result – the number of amps the unit uses to run. These are not starting amps. A boost in starting amps is achieved through the use of a built-in start capacitor which stores extra energy to use the next time the compressor starts.

Did you know? Pick HVAC has also developed a BTU to Watts Calculator if you’re interested in how many watts your unit uses. You’ll need to know the EER, not the SEER, for your AC.

If all you know is the SEER, use the Pick HVAC EER to SEER Calculator to find EER. Input SEER, and the EER rating will automatically be calculated.

How Many Amps Does an AC Use? Summary Amperage Chart

This central air conditioner amperage chart is based on 16 SEER, the most common AC efficiency. It’s for quick reference. Once again, the calculator is the way to find the most accurate information.

How many amps does a 1-5 Ton ac unit draw?

Air Conditioner Capacity (Ton)BTUAmps
1 Ton12,000 BTU3.73 amps
1.5 Ton18,000 BTU5.59 amps
2 Ton24,000 BTU7.45 amps
2.5 Ton30,000 BTU9.32 amps
3 Ton36,000 BTU11.18 amps
3.5 Ton42,000 BTU13.04 amps
4 Ton48,000 BTU14.91 amps
5 Ton60,000 BTU18.63 amps

* Based on 230v and 16 seer.  

Amps = BTU / ((SEER*0.875) x Volt)

How do you use the chart? A few examples will help.

Example 1: How many amps does a 5 ton AC draw?

Find 5 Ton in the Air Conditioner Capacity column at the left of the table. The center column shows the equivalent in BTU. Amps is in the right column. A 5 ton AC draws 18.63 amps if it is 16 SEER. Use the Calculator to determine how many amps a 5 ton AC uses if it is not 16 SEER.

Example 2: How many amps does a 3 ton heat pump use?

A heat pump and an AC use the same amount of electricity when in AC mode. So, find 3 Ton in the left column. In the right column, find your answer. A 3 ton 16 SEER AC draws 11.18 amps. The more efficient the 3 ton AC is, the fewer amps it draws.


Here are related questions with answers.

What size wire for a 15-40 amp circuit?

Wire size needed for 15 to 40 amp breaker capacities ranges from #6 to #14. This Breaker Wire Size Chart gives details.

Total Unit AmpsCircuit Breaker AmpsWire Size
0-12 Amp15 Amp14 Gauge
13-16 Amp20 Amp12 Gauge
17-24 Amp30 Amp10 Gauge
25-32 Amp40 Amp8 Gauge
33-48 Amp60 Amp6 Gauge

10/2 or 10/3 wire for air conditioner?

10/2 is the standard choice for a central AC or air conditioner of any kind. This is because a 10/2 wire is appropriate for appliances using one voltage.

A 10/3 wire is used for dual voltage machines. For example, an electric clothes dryer motor runs on 120V and the heat elements require 240V, so a 10/3 wire would handle both.

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.

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