Air Conditioner Power Consumption: Deciphering The Label

By Nicholas BrownFollow me on Twitter.

The power consumption of air conditioners averages 318 watts (hourly, for a 24,000 BTU unit) in most American households. The power draw of a unit that size ranges from 1,800 to 2,500 watts in most cases. However, that is only when the units are operating at full speed. Air conditioner power consumption trumps that of most appliances.

The average power consumption of air conditioners is only 318 watts because air conditioning units automatically cycle their compressors on/off as needed throughout the day. The power consumption of inverter air conditioners is often more than 60% lower than standard units. This is because they regulate compressor speed and refrigerant flow instead of operating at full speed.

Inverter air conditioner units have the disadvantages of a high initial cost as well as costly non-standard (proprietary) parts that are more difficult to find.

The 318-watt average mentioned (source: U.S. DOE) adds up to 228 kWh per month. That would cost:

Currency: USD.

$27.36 at an electricity rate of $0.12/kWh (this is the average electricity rate in the U.S.).

$45.60 (€41.87) at a rate of $0.20/kWh. $0.20 is a common rate in Europe (many European countries are in the range of $0.19 to $0.25/kWh).

$79.80 at a rate of $0.35/kWh.

$102.60 at a rate of $0.45/kWh.

Power Consumption Calculator

Kompulsa has a power consumption calculator that you can use to calculate the power consumption of various appliances. It can also be used to calculate fuel requirements for a trip and your MPG.

Get it on Google Play

You can also use the browser-based version of it.

The operational cost of an air conditioner is dependent on multiple factors. The key one is the size of the room you’re cooling, and the unit size is dependent on your room size. Look for the unit size that corresponds to the room that you are cooling below (for example: if your room is 500 square feet and is located in the United States, you would skip to the 12,000 BTU section).

If you’re also seeking information on refrigerator power consumption, Kompulsa has a page dedicated to that, with the power consumption data organized by refrigerator size and configuration.

A/C condensing units
Air Conditioner Condensing Units. Image obtained with thanks from chooyutshing on Flickr.

Please note that air conditioner energy usage is heavily influenced by the temperature of your environment and your thermostat temperature. The room size recommendations below were obtained from the U.S. Department of Energy.

The cumulative energy usage and energy cost estimates on this page are estimated and not intended for budgetary purposes. All cost figures on this page refer to electricity cost unless otherwise stated. Use the information provided herein at your own risk.

The power consumption of air conditioners is determined by two factors: Runtime, or compressor speed. In the case of a non-inverter/single speed unit, the compressor speed remains the same at all times and the unit shuts off when the desired temperature is achieved. Power consumption is determined by the unit’s runtime in hours multiplied by its wattage.

The power consumption of inverter air conditioners can be controlled in real time because increasing the thermostat temperature decreases compressor speed, thereby reducing power consumption immediately. To determine the average power consumption of your own air conditioner, you can plug it into an energy use meter.

Table Of Contents
How To Determine Air Conditioner Efficiency.
Are Air Conditioners Expensive To Operate?
Effect Of Air Conditioner Size On Power Consumption.
Power Consumption Of Air Conditioners Ordered By Unit Size.
How Much Power Do 5,000 BTU Air Conditioners Use?.
Energy Usage Of 9,000 BTU Air Conditioners.
Power Usage Of 12,000 BTU Air Conditioners.
Energy Consumption Of 18,000 BTU Air Conditioners.
Power Consumption of 24,000 BTU Air Conditioners.
Energy Usage of 28,000 BTU Air Conditioners.
Reducing Air Conditioner Energy Usage.
Inverter Air Conditioners Vs Standard Units.

How Does One Determine The Efficiency Of An Air Conditioner?

Fortunately, room air conditioners come with an EER rating. EER means Energy Efficiency Ratio. The EER is the ratio of an A/C unit’s cooling capacity to its wattage. Therefore, a 24,000 BTU [PDF] unit with an EER of 10 draws 2,400 watts (24000 / 2400).

Due to the exceptionally high power consumption of air conditioners, it’s ideal to purchase a unit with an EER above 11. These are easy to find.

The label of an 18,000 BTU air conditioner.

Of all the electrical ratings printed on the label above, the only one relevant to your electric bill is the one marked ‘STD INPUT POWER’. That is the unit’s wattage.

The unit won’t draw as much as the locked rotor current unless it fails to start (due to a locked rotor, that is), and the ‘MAX. INPUT CONSUMPTION’ is the initial startup power consumption. It won’t draw this much current for more than a few seconds, and is therefore irrelevant to your electric bill.

The Capacity Btu/h rating is just the air conditioner’s cooling capacity, measured in BTUs. It indicates that this is an 18,000 BTU unit. We can now conclude that the EER of this unit is 9.47 by dividing the BTU/h rating (18,000) by the standard power input rating (1900). This is common, but not the best. Remember, a higher EER is better!

For environmental reasons, ensure that the refrigerant (marked ‘REFRIG’ on this unit) is R410A, and not R22, as R410A won’t cause ozone layer depletion. Almost all new household air conditioners use R410A, so they are easy to find. R22 units are also getting more expensive to repair because that refrigerant is being phased out/is increasingly scarce.

Are Air Conditioners Expensive To Operate?

Yes, air conditioners are expensive to operate due to their high electricity usage. If you’re only air conditioning one room, the cost of operating an air conditioner would be dramatically lower than if you were air conditioning 3 or more rooms. Room size is also an important factor, but generally — more rooms translates to a higher HVAC bill.

What percentage your air conditioner’s power usage of your overall household energy usage is determined by what kind of appliances you have. For example: If you have minimal lighting (one bulb per room with no recessed lighting), then lighting should account for a lower percentage of your energy usage.

However, if you have several high-wattage incandescent light bulbs per room, that could quickly add up to a massive electric bill. You can determine an air conditioner’s cost of ownership by adding how much power the air conditioner uses over time to all other expenses associated with it.

You can reduce energy usage by only turning on the AC in the room that you’re going to spend most of your time in for the day (that could be your home office or bedroom, for example). You’ll survive in the other rooms if you don’t stay in them for long!

Effect Of Unit Size On Air Conditioner Power Consumption

In some cases, very large units have a slightly lower EER (this means that they use more energy) than the average unit. However, smaller air conditioners may end up costing you more due to common habits.

Small units take long to cool off if used in rooms larger than the recommended size, so you may be reluctant to turn them off because you won’t want to wait for them to cool back off later (this is a terrible waste of energy). To avoid waiting, some people may buy slightly larger air conditioners.

Bear in mind that this article is not intended to help you to choose a unit size based on the average efficiency of that size unit. You should skip to the section that corresponds to the unit size required by your room.

Disclaimer: The information provided below is not intended for budgetary purposes, it is estimated. Use it at your own risk.

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If you’re also seeking information on refrigerator power consumption, Kompulsa has a page dedicated to that, with the power consumption data organized by refrigerator size and configuration.

Power Consumption Of Air Conditioners – Ordered By Unit Size

NB: The air conditioner sizing data below does not apply to megathermal climates and assumes 24 hours/day usage.

Power Consumption Of 5,000 BTU Air Conditioners (0.41 Tons/1.4 kW)

5,000 BTU air conditioners are recommended for rooms less than 200 square feet (ideally less than 150 square feet).

The wattage of 5,000 BTU air conditioner units averages 446 to 580 watts (most of the units assessed for this average were window units, as 5,000 BTU split units are uncommon).

People often buy 5,000 BTU air conditioners for college dormitories and small apartments. They are usually window units. People often buy these window air conditioners because they are more DIY-friendly and can be installed without cutting holes in your landlord’s wall.

Estimated Monthly Energy Usage:

51 to 59 kWh

At the U.S. national average electricity rate of $0.12 per kWh, that works out to:

$6.12 to $7.08/Month

Thermostat temperatures above 25 °C are assumed. This does not include inverter air conditioners.

You can find and buy the most energy-efficient 5,000 BTU air conditioners with the help of our air conditioner finder, and it orders units by power consumption!

Power Consumption Of 9,000 BTU Air Conditioners (0.75 Tons/2.6 kW)

The power consumption of 9,000 BTU air conditioner units ranges from 800-900 watts. If a 9,000 BTU A/C unit consumes more than 900 watts, it is inefficient and you should look for a better model. 9,000 BTU A/C units are recommended for rooms that are 350-400 square feet.

If you need to purchase a 9,000 BTU air conditioner for a 350-400 square foot room, you might be able to buy a 10,000 BTU or 12,000 BTU air conditioner instead under certain circumstances (please contact a professional to advise you on this), as these will cool your room quicker.

Bear in mind that you should not purchase an oversized unit, as this may compromise the air conditioner’s performance and even promote mold growth due to excessive humidity.

They will not incur a significantly higher electricity cost than smaller units because they don’t need to run as long as the smaller ones (assuming that you’ll purchase an inverter model). The average energy usage of the common 24,000 BTU air conditioners is slightly higher because they have a lower EER.

Estimated Monthly Energy Usage:

71 to 95 kWh

At the U.S. national average electricity rate of $0.12 per kWh, that works out to:

$8.52 to $11.40/Month

Thermostat temperatures above 25 °C are assumed. This includes both inverter and non-inverter units.

You can buy 9,000 BTU air conditioners, and find the most energy-efficient units ordered by energy usage with the help of our air conditioner finder.

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Power Consumption Of 12,000 BTU Air Conditioners (1 Ton/3.5 kW)

12,000 BTU air conditioner units consume 991 (EER: 12.1) to 1,333 watts (EER: 9, which is a bit low for these units, by today’s standards). An EER of 11.3 is average for new 12,000 BTU window units, translating to a wattage of 1,061 Watts.

Please don’t buy air conditioners with an EER below 11 (in other words, don’t buy anything with a wattage exceeding 1,090 Watts) if you’re shopping for a 12,000 BTU unit. A/C units with an EER of 12 are so common that you won’t have any trouble finding them. There are units with EERs greater than 11 for well under $800 USD. Your wallet will thank you later.

Try Kompulsa’s energy usage calculator.

12,000 BTU units are recommended for rooms ranging from 450-550 square feet.

Also Read: Heater Power Consumption, Ordered By Unit Size.

Estimated Monthly Energy Usage:

92 to 122 kWh

At the U.S. national average electricity rate of $0.12 per kWh, that works out to:

$11.04 to $14.64/Month

Thermostat temperatures above 25 °C are assumed. This includes both inverter and non-inverter units.

You can buy 12,000 BTU air conditioners, or just browse them ordered by energy usage with the help of our air conditioner finder.

Electrical Ratings
Amperage

The amperage of 12,000 BTU units I checked ranged from 3.5 to 5.1 amps (these current ratings were obtained from the specifications of five different 220 volt models, including both inverter and non-inverter air conditioners).

Power Consumption Of 24,000 BTU Air Conditioners (2 Tons/7 kW)

24,000 BTU A/C units are a little less efficient than their smaller counterparts, with an EER range of 8.5 to 12.5 for new units (this applies to both split and window units). They typically draw 2,500 to 2,823 watts.

You can determine and average the power consumption of your air conditioner using a ‘Kill A Watt’ or similar energy use monitor and compare its energy usage to that of modern units, as well as the figures provided herein.

For that reason, they are still a good option (not that you have a choice, as some rooms require units of this size). People with smaller units may not want to turn them off because they might take too long to cool back off when they return.

Try Kompulsa’s energy usage calculator.

This means that the energy usage of a 24,000 BTU air conditioner could, in practice, be lower than that of a 12,000 BTU unit (assuming it is used in the same room).

In the United States, the power consumption of 24,000 BTU household air conditioner units averages 228 kWh/month (source: DOE).

The DOE recommends these units for rooms ranging from 1,400-1,500 square feet, but that isn’t a requirement.

This amounts to an average cost of $27 USD/month. An inverter air conditioner might provide energy savings up to 60%, depending on the circumstances.

Also Read: Heater Power Consumption, Ordered By Unit Size.

Electrical Ratings
Amperage

The current rating of 24,000 BTU air conditioners is often in the range of 8.4 amps to 12.7 amps. This data was obtained from the labels of six 220 volt units of the following brands:

  • Pioneer.
  • Senville.
  • General Electric.
  • Friederich.
  • Haier.
  • LG.

You can find the most efficient 24,000 BTU units (sorted by monthly energy usage) using our air conditioner finder. It also provides a (rough) monthly electricity cost estimate. You can also purchase the air conditioners using the links provided.

Thermostat temperatures above 25 °C are assumed. This includes both inverter and non-inverter units.

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