How Many Amps Does An Air Conditioner Use? (5,000-18,000 BTU)

How Many Amps Does An Air Conditioner Use

The AC is often one of the biggest purchases people make in their lifetimes. It’s sort of like investing in a house if you think about it. One takes into account factors like the cost, lifespan, and usefulness before they buy one that is tailored to exactly fit their needs.

The AC, then, is almost a vital component of your home. More so now than ever, with unpredictable climates and temperatures taking the lead- an AC is something of a necessity, even to those people who are operating on a budget.

One of the biggest determining factors that should play a significant role in the purchase of your AC has a lot to do with its electricity needs.

Many people tend to be conscious of things like BTU sizes, SEER ratings (Seasonal Energy Efficiency Ratio) while looking for the perfect AC.

Some even check on the Watt usage of their AC. These units are usually a measure of how much current your AC will withdraw when it starts working.

The thing is, you must start thinking about the future of your AC even before you’ve bought one.

Because these units tend to bear down on their owners’ wallets with repair and replacement costs, as well as electricity costs- which can be a huge drain on you if you choose your AC without much care for its Ampere usage.

This article is aimed at guiding you through AC Amps and how they become important in determining the effectiveness of your AC unit.

The Amp or The Ampere

Amperes are units used to represent how much electricity is traveling or being transferred from one place to another within a given period of time. Amps, naturally, vary as per the size of the appliance within which they operate.

That is, as a general rule, it is safe to assume that a bigger AC unit will be more accommodating of a bigger Amps rate compared to a smaller unit. 

Amps are concurrent to the amount of electricity drawn to run an appliance. In the case of an air conditioner, amps usually run from circuits to the air conditioning units, and the electricity drawn to run the unit varies as per the requirement of the AC, which is dependent on the size.

Amps, then, are also directly proportional to the BTU rating of your AC. The BTU or the British Thermal Unit is used to estimate the area of space an AC unit can cool perfectly.

The BTU prescribes the size of a room that an AC can cool in square feet. AC’s vary in BTU sizes ranging from 5,000 to 24,000 and so on.

Why Is It Important To Know The Ampere Rating Of Your AC?

The Ampere rating is not something particularly noteworthy, yet this simple unit can dictate a large part of your AC’s energy savings. As you know, the Ampere is indicative of your AC unit’s current draw at any given point in time.

This correlates directly to electricity costs, as a higher current draw can weigh heavier when you pay your monthly current bills. However, the Ampere is not standalone in determining the energy-saving capacity of your unit.

The Big Equation- How to Find your AC’s Amps usage and more?

The Ampere, along with the system’s Voltage as well as the Watt usage together finally estimate how much electricity is used up in running the entire AC unit. The relation between the three measures is as given below:

Power (in Watt)= V (Voltage) X I (Amperes).

The total power consumption of the AC can be deduced by multiplication of the number of Volts with the number of Amperes consumed by a unit. Conversely, we can also compute the number of Amps consumed by dividing the total Power (Watts) by the Voltage.

However, there’s usually no need to do this, as you’ll find all details pertaining to the Watts, Voltage, and Amps used in the AC’s manual of specification sheet provided by the manufacturer.

But if you are not able to find any specific measure, such as the Amps, these formulas can be helpful in calculating whatever you require.

A much easier way to find out the Amps used by an AC unit is through the BTU capacity and the EER rating. This formula is as follows:

I (Amps) = BTU capacity/ EER X V (voltage).

For instance, let’s assume an Air Conditioner has a BTU capacity of 10,000. Usually, small-sized AC units are expected to draw no more than 120 V. Additionally, with a 10 EER rating, one can conclude that:

I (Amps) = 10,000/10 x 120 = 8.33 Amps.

Thus, the 10,000 BTU AC unit, at 120 V draws a current of 8.33 Amps from the circuit.

Usually, the EER also plays a big role in determining this number, since the EER rating can vary for different AC units across the market of the same size and Voltage requirement.

It is, then, an easy tool of comparison between different units as it can be used to see which unit draws the least amount of current, and will predictably lower future electricity costs.

For instance, if you take the same 10,000 BTU rated unit from the above example, and tweak its Energy Efficiency Ratio to a higher number, you would find the Ampere unit would lessen:

I (Amps) = 10,000/12 x 120 = 6.94 Amps

Here, the EER rating is 12 and yields a lower Ampere rating of 6.94 Amps. As a result, this would also lessen the overall power consumed by the unit when you integrate this number to the equation of P(Watts) = V (Voltage) x I (Ampere). 

The total Watt usage of the entire unit would be equal to the result of V x I, that is, 120 x 12, which would give us a much-lowered watt rating of 1,440 (as compared to the Watt usage at a lesser EER).

How Many Amps Does your Air Conditioner Use?

With most Air Conditioners, the typical assumptions are that a small AC unit can absorb around 7.5 Amps of electricity on a standard 110-120 Volt Circuit.

Similarly, at 120V, a medium-sized AC unit will be supplied with about 15A. When it comes to larger units (for example, multi-zone mini split AC systems), you’ll need a 240V circuit to support the unit’s current draw of about 30A.

On average an air conditioner uses this much Amps:

  • A 5,000 BTU AC unit uses: 3.62 to 5.43 Amps
  • An 8,000 BTU AC unit uses: 5.80 to 8.70 Amps
  • A 10,000 BTU AC unit uses: 7.25 to 10.87 Amp
  • A 12,000 BTU AC unit uses: 8.70 to 13.04 Amps
  • A 15,000 BTU AC unit uses: 10.87 to 16.30 Amps
  • An 18,000 BTU AC unit uses: 13.04 to 19.57 Amps

The importance and consequence of Amps usage in an AC

The reason why Ampere rating becomes so crucial is that it helps a customer see whether an AC is suitable for your home. 

Your house itself has a regulated circuit system from which all electrical appliances draw to run. Your AC will become a part of that system.

So it is important that your AC unit’s ampere withdrawal can be adequately supported by your circuit without hindering the functioning of any other household appliances. 

Thus, it is advised that you do not buy an AC that uses more amps than what your circuit can support. What this means is that if your circuit can only provide up to about 15A, don’t choose a unit that required 19Amps to run. 

The consequence of such a situation is that the excessively drawn amps will trip the circuit altogether. High Ampere draws can also lead to over usage of the equipment, and ultimately cause quicker wear and tear of the AC unit. 

Additionally, it can also cause sudden failure of the AC unit- your Air Conditioner’s lifespan might expire faster than predicted.

However, there are also possibilities where you might have bought an AC that draws lower Amps than what the circuit is providing for your AC. While this doesn’t usually cause an issue, there are rare cases where it might affect the AC’s compressor and reduce the lifespan.

Ideally, you should have an AC that draws the right amount of Amps provided by your circuit. If you’re unsure about your home’s circuit system, a casual check-in from your electrician should clear the way ahead.


However, with all the electricity specifications lining up between your AC unit and the house, along with the added advantage of a relatively high EER, you can expect to get some great cuts and reduced charges on your power bill. Regular maintenance and cleaning of your AC will also help keep your AC working smoothly and efficiently for a long time to come.

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