How Much Electricity Does an AC Unit Use? [With Calculator]

| Last Updated: December 28, 2020

The calculator below will calculate the amount of electricity, in wattage, that is used to operate different types of AC units. To get started, select the AC unit you own from the dropdown menu, select the appropriate daily usage and then your cost per KW/H.

  • Type of AC Unit: Select the type of air conditioner that is appropriate for your situation.
  • Average Daily Use: Currently set at 3 hours per day on average based on 12 hours used during the 3 summer months and zero the rest of the months. Please adjust this accordingly based on where you live and how much you will run the AC unit for.
  • KW/H Price: Currently set at an average of $0.136 per kilowatt hour, which is the US average. Please refer to the current prices in your area for the most accurate cost estimation. The full list of KW/H prices by state can be found below the calculator.

KW/H Prices by State

Find your state in the list below and use the most accurate KW/H price in the calculator.

StateKW/H Price
Alabama$0.131
Alaska$0.232
Arizona$0.121
Arkansas$0.108
California$0.208
Colorado$0.124
Connecticut$0.227
Delaware$0.139
District of Columbia$0.136
Florida$0.115
Georgia$0.120
Hawaii$0.290
Idaho$0.103
Illinois$0.140
Indiana$0.140
Iowa$0.125
Kansas$0.131
Kentucky$0.117
Louisiana$0.106
Maine$0.169
Maryland$0.139
Massachusetts$0.216
Michigan$0.168
Minnesota$0.136
Mississippi$0.115
Missouri$0.111
Montana$0.116
Nebraska$0.114
Nevada$0.041
New England$0.211
New Hampshire$0.193
New Jersey$0.159
New Mexico$0.134
New York$0.193
North Carolina$0.120
North Dakota$0.106
Ohio$0.130
Oklahoma$0.108
Oregon$0.114
Pennsylvania$0.139
Rhode Island$0.224
South Carolina$0.132
South Dakota$0.125
Tennessee$0.112
Texas$0.119
Utah$0.103
Vermont$0.201
Virginia$0.125
Washington$0.100
West Virginia$0.130
Wisconsin$0.148
Wyoming$0.117
Data accurate as of October 2020. Source

How Much Power Does my AC Use?

The amount of power (watts) used by your air conditioner will be based on the size of it (BTU) and the efficiency of the unit (EER). BTU stands for British Thermal Units and is a common way AC units are sized. EER stands for Energy Efficiency Ratio, which is a score assigned to units based on how efficient they are. The higher the score the better.

Now that the definitions are out of the way, we can use these two units (BTU and EER) to determine the estimated wattage use of your AC unit.

The formula is as follows: BTU / EER = Wattage

A Quick Example

Your air conditioner is a 12,000 BTU window unit that has an EER rating of 9.5. To find the required wattage you would do the following:

12,000 BTU / 8.5 EER = 1,263W

Wattage Requirements for Common AC Sizes

Below are some of the more common single room AC unit sizes in BTUs and their watts required to power them. We are using an average of 9.5 EER for these examples.

AC Size (in BTUs)WattsYearly Cost ($.136 KW/h)
5,000 BTU526W$358
6,000 BTU632W$515
8,000 BTU842W$916
10,000 BTU1,053W$1,432
12,000 BTU1,263W$2,061
14,000 BTU1,474W$2,806
15,000 BTU1,579W$3,221
18,000 BTU1,895W$4,638
25,000 BTU2,632W$8,947

AC Unit Types vs. Watts

The type of AC unit will determine the range of watts that will be required to power it. This is due to some ac unit types being more efficient and other types, such as central AC, cool a much larger space which requires more power.

There are two main categories for AC units:

  • Central Air Conditioning
  • Single Room Units

Central AC

The most important thing to know here is that central AC units cool your entire home. This requires a lot of power to do this which is why the amount of watts will be higher compared to single room units.

Single Room Units

Single room units are used to only cool one room. This requires much less power since you are cooling a smaller space. Some examples of single room units include window air conditioners and portable air conditioners.

My name is Bob Wells and I am a retired HVAC tech from Washington state. I am currently retired and no longer do much with HVAC, however, I feel like I have a lot of knowledge in the subject and I wanted to create a website where I could talk about what I've learned and help upcoming HVAC techs. Find more info about me and HVAC Training 101.