How Much Electricity Does A Window AC Use?

When shopping for new appliances, like a window air conditioner, one of the important things you should look for is its power consumption. It helps in estimating the cost of your energy bill. But you may wonder, how much electricity does a window AC use? Here is what you need to know.

A window air conditioner can consume anywhere from 500 to 1,500 watts of electricity to run. Depending on the size of your AC unit, the electricity used by window AC are as follows: 

  • 5,000 BTU window AC- 550 Watts
  • 8,000 BTU window AC- 660 Watts
  • 10,000 BTU window AC- 900 Watts
  • 12,000 BTU window AC- 1,100 Watts
  • 15,000 BTU window AC- 1,500 Watts

Read on to know more about window air conditioner units, how to compute your energy bill, factors affecting your window AC power consumption, and more. 

And old styled air conditioner on the wall - How Much Electricity Does A Window AC Use

How To Compute Window Air Conditioner Monthly Power Consumption?

Watthour meter of electricity for use in home appliance.This is a modern technology that can monitor the home's electrical energy consumption

To compute your air conditioner's monthly electrical use, you need to: 

  1. Know the number of hours your window AC operates in a day.
  2. Determine the power consumption of your window AC unit (Watts). 
  3. Calculate the monthly electrical using this formula: 
    • AC power consumption (Watts) x AC operation time in a day (hrs) x Number of days

For example, to compute the monthly electrical use of a 5,000 BTU window AC, given that your AC operates 8 hours on a day and its power consumption is 550W:

            AC monthly electrical use= (550W x 8hrs/day x 30 days)/1000

             AC monthly electrical use= 132 kWh

How To Compute A Window AC Monthly Electrical Bill Cost?

To compute your air conditioner's monthly electrical cost, you need to: 

  1. Know the electricity cost in your locality ($/kWh); and
  2. Determine the power consumption of your window AC unit in a month (kWh). 
  3. Calculate the monthly electrical using this formula:                             electricity cost ($/kWh) x monthly window AC power consumption

For example, to compute the monthly electrical use of a 5,000 BTU window AC, given that the US national average electricity price is $0.13/kWh and the monthly power consumption is 132 kWh: 

           AC monthly electricity cost= $0.13/kWh x 132 kWh

           AC monthly electricity cost= $17.16

However, this is only a guide for you to know how to compute your monthly AC energy bill. There are still factors that may affect it, like your local electricity cost for one. 

What Are The Factors That Influence How Much Energy Your Air Conditioner Uses?

The electricity usage of your window air conditioner is influenced by several things. These factors include:

  • Ambient Temperature
  • Size of your AC
  • Local Climate
  • Thermostat Setting
  • Unit's EER/SEER/CEER Rating
  • Cooling Load

Other factors like indoor temperature, dirty air filters, and house openings also affect your air conditioner's energy consumption.

How Does Ambient Temperature, Indoor Temperature, And Local Climate Affect AC Energy Consumption?

The temperature difference between the outside air and the refrigerant determines the amount of heat transferred and the rate at which it is transferred.

When the temperature outside rises, the air conditioner has to work harder to cool the house because the compressor has to work harder.

In addition, the temperature at which you set the window AC might have an impact on how much electricity it consumes. The appliance requires more energy to cool the space when the cooling cycle starts.

When the desired temperature is reached, the cooling cycle is turned off, and only the fan operates—using far less electricity.

Aside from heat, humidity is an important aspect of the environment in your area. This is important because places with high humidity necessitate the use of more powerful air conditioners.

The result of your air conditioner's hard work will be reflected in the higher power bills you'll receive at the end of the month.

What Is The Difference Between EER, SEER, and CEER Ratings of AC Units?


EER is a rating that evaluates how much cooling an air conditioner offers for each unit of electrical energy it consumes in a steady-state operation.

Dividing the unit's cooling capacity in BTUs/hour by the power input in watts at a given temperature will give you the EER of your air conditioner.


An air conditioner's cooling capability is expressed as a percentage of its power intake in the SEER or seasonal energy efficiency ratio. The SEER rating is a measurement of how successfully a unit cools. SEER ratings of 6 or below are common in older air conditioners. 

Low SEER air conditioners (SEER rating <10) use more electricity than regular SEER air conditioners (10). Models with a SEER rating higher than this are typically more efficient, such as inverter air conditioners, which have a SEER of 14.5.


CEER is a rating used to evaluate a window or room air conditioner's realistic energy efficiency. It calculates the unit's overall efficiency in both standby and cooling modes.

CEER aids in determining the size of the air conditioner required for a single room. Window air conditioners with Energy Star certification have a SEER of 14.5.

Note: SEER is more common in central air conditioners and heat pumps, but EER and CEER are more common in window air conditioners. 

How Does Thermostat Setting Impact Air Conditioner's Power Consumption?

A common misconception of some homeowners is that when they set the thermostat to a lower temperature, it takes lesser time compared to setting the thermostat to a higher one. But this idea is not true. 

Instead of the cooling time, setting your thermostat to a lower temperature will AC's power consumption. 

How To Reduce Air Conditioner's Power Consumption?

And old styled air conditioner on the wall.

If soaring electricity costs have you considering ways to cut back on your usage, you'll be relieved to find that you can do so without sacrificing your level of living.

Here are ways on how you can save your electricity consumption:

  • Raise the temperature.
  • Keep your AC clean.
  • Schedule your AC maintenance regularly. 
  • Invest in a smart thermostat.
  • Seal your windows.
  • Properly insulate your home.
  • Use a fan during colder days.

You can lower electricity use to save money on your monthly power bills and do your part to protect the environment if you become aware of your energy usage and examine the areas of your home where electricity is wasted. 

What Is A Smart Thermostat?

Remote home control system on a digital tablet or phone.

A smart thermostat can be operated via an internet-connected device such as a phone, tablet, smart speaker, or other internet-connected devices. You can program these thermostats to your preferred temperature settings and can also be integrated into your automation systems.

How Does A Smart Thermostat Work?

To better understand how a smart thermostat works, you have to know first how a regular thermostat works. 

A regular thermostat decides when the fan, AC, or heat should be turned on and off using the temperature. It functions similarly to a light switch, only that temperature is factored into the equation.

Smart thermostats are similar to regular thermostats, except that they connect to the home's Wi-Fi network. You can use a partner app to alter the thermostat's settings remotely.

When you enter a temperature setting into the app, it sends that information to the thermostat over your Wi-Fi network, and the thermostat then sends that information to the blower and HVAC system.

What Are The Advantages Of Using A Smart Thermostat In A Window AC Unit?

Smart Thermostat with a person saving energy with a smart device on a white background

Here are some advantages of using a smart thermostat in your window AC unit: 

  • Energy-saving. According to the U.S. Department of Energy, if homes use air conditioners with smart thermostats, they can save at least 10% per year on average from heating and cooling.
  • Convenient. Smart controls provide the ultimate peace of mind, allowing you to control your air conditioner from anywhere you are.
  • Detect dirty AC filter. Smart thermostats can detect how much your AC filter has been used and notify you when it needs to be replaced.
  • Set AC cooling/heating schedule. Smart thermostats allow you to set customized schedules so you don't have to fiddle with the AC modes every day.
  • Monitor your AC unit usage. Using smart thermostats, you can now get a detailed breakdown of your usage over the previous month.
  • Use voice commands. By using smart thermostats, you can have the ability to use voice commands on your window AC unit. 

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In Closing

While it is true that air conditioners are power-consuming, there are still some ways to conserve energy. With the advent of technology, devices like smart thermostats can aid in cutting your monthly electricity costs. 

In addition, small things like closing open doors or windows and properly insulating your home can also help. But most importantly, always remember to use your air conditioner only when it is needed. 

If you want to learn more about HVAC systems' power consumption, be sure to check these related articles:

How Much Power Does A Portable Air Conditioner Use? [By BTU]

How Much Power Does A Furnace Blower Use? [Amps And Watts]

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