How Much Electricity Does an Air Conditioner Use?

This AC electricity usage guide offers answers to your questions about air conditioner power consumption, average home electricity usage, and how to calculate what size air conditioner you need for your home.

We also include an Air Conditioner Electricity Usage Table that will help you find the answer to questions like “How much electricity does a 5,000 BTU air conditioner use per hour?”

This table will provide examples for common air conditioner and room sizes, and will also offer a calculation tool so that you can do your own custom calculations!

Air Conditioner Electricity Consumption Calculator:

Air Conditioner Electricity Consumption Calculator

This calculator will give you the air conditioner power consumption per hour and per month, so that you can get a fuller understanding of how much electricity you are using.

To use the calculator, enter the air conditioner capacity (BTU) of your AC unit, and the EER (Energy Efficiency Ratio). The result will be provided in Kilowatts (kWh). If you would rather have the answer in Watts, you can simply multiply the answer in kWh by 1,000. 1 Kilowatt = 1,000 Watts.

Air Conditioner Electricity Usage Table

The table below offers the electricity usage of a 5,000 – 18,000 BTU air conditioner.

A helpful rule of thumb for calculating the electrical usage of an AC unit with 10 EER efficiency, a common efficiency rating, is that 1,000 BTU uses 0.10 Kilowatts (100 Watts) per hour. If the EER is lower, it will use more electricity; If higher than 10, it will consume less energy.

AC Capacity (BTU)Electricity Consumption 
Per Hour
Electricity Consumption
Per Month
5,000 BTU0.50 kWh360 kWh
6,000 BTU0.60 kWh432 kWh
8,000 BTU0.80 kWh576 kWh
10,000 BTU1.00 kWh720 kWh
12,000 BTU1.20 kWh864 kWh
14,000 BTU1.40 kWh1008 kWh
15,000 BTU1.50 kWh1080 kWh
18,000 BTU1.80 kWh1296 kWh

* Based on 10 EER.

Example 1: How much electricity does a 12,000 BTU air conditioner use in a month?

Using the chart, you can answer this question. A 12,000 BTU air conditioner uses 864 kWh in one month.

Example 2: What AC capacity uses 1.00 kWh or less?

You can see from the chart that a 10,000 BTU AC uses 1.00 kWh, so anything smaller than 10,000 BTU will use less than 1.00 kWh.

Example 3: How much electricity does a 5,000 BTU air conditioner use?

5,000 BTU air conditioner uses 0.50 kWh per hour, and 360 kWh per month.

How to Manually Calculate Electricity Use

You may find yourself in a circumstance where it’s not convenient or possible to use our online calculator tool. In that case, you’ll need to know how to manually calculate the electricity use of an air conditioner!

Here’s how to do it:

Say you have a 6,000 BTU window AC and you want to know how much electricity it is using each month.

How much electricity does a 6,000 BTU air conditioner use per month?

The formula for efficiency use is BTU/EER/1,000. So, here are the steps to answering the question.

Step 1: Divide your AC unit’s BTU by its EER rating, and then divide that number by 1,000. Consider an AC with 10 EER efficiency.

6,000 divided by 10 EER is 600. And 600 divided by 1,000 is 0.60. This number is the Kilowatts per hour that your AC is using.

Step 2: Take the kWh number and multiply it by the number of hours in a month, which is approximately 720.

0.60 multiplied by 720 is 432. This number is the kWh that your AC uses in a month.

Answer: A 6,000 BTU window air conditioner uses 0.60 kWh per hour and 432 kWh per month

AC Electricity Saving Tips

Now that you have an idea of how much electricity your window AC or portable AC is using, you may be wondering how to keep that number low! We offer some tips below for how to reduce electricity consumption when running AC and keep your electric bill low.

1. Clean the filter – Keeping your AC’s filter clean and free of debris can have a big impact on the efficiency of the unit. Experts recommend replacing the filter every four to six weeks for maximum efficiency.

2. Insulate the area – Did you know that a well-insulated house can save you about 15% on your electricity bill? Even small changes can have a big impact on how well a room retains cool air. For example, make sure that your doors and windows don’t have any cracks where outside air can seep in. If they do, add a lining that will keep cool air inside and stop warm outside air from coming in.

3. Turn the thermostat up a few degrees – The average home electricity usage is about 860 kWh per month. You can lower your electricity bill by keeping your house a little warmer and your AC thermostat lower.


1. What uses more electricity, an air conditioner or a fan?

An air conditioner uses significantly more electricity than a fan. A ceiling fan uses about 75 Watts of electricity per hour, while an average window AC unit uses about 1,000 Watts per hour.

2. Which uses more electricity, a window AC unit or central air?

Central air uses about two thirds more energy per hour than a window unit uses. So, you can cut your electricity costs by using the central air less and getting a window air conditioner to cool just the room you’re using at the time.

3. Does leaving the AC fan on waste electricity?

In short, yes. It is estimated that running the fan on a window AC uses as much power as running a refrigerator. In addition, keeping the fan running does not cool the house down the way the AC does. Fans cool using the “wind chill” effect, not by lowering the temperature of the room.

4. What is the ideal AC temperature to save electricity?

The Department of Energy says that 78 degrees Fahrenheit is the ideal temperature to save electricity and maintain a comfortable environment.

5. Does Turning Off AC Save Electricity?

Turning off your AC in hot weather can actually have a negative effect on your electricity usage, because your AC will have to work harder to cool your house down later. Instead, consider using “eco” or power saving mode, which automatically turns off your AC once the room has reached the desired temperature.

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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