# How much electricity does a window AC use?

When it comes to understanding the electricity usage of a window air conditioner, it’s essential to grasp the concept of Electrical Energy.

Electrical energy is the unit of measurement that determines your monthly electricity bill. For example, In the United States, it is typically measured in kilowatt-hours (kWh), and for every 1 kWh of energy your appliances consume, the utility company will charge you an average of 15 to 17 cents, varying according to your location.

Now, like any other type of air conditioner, the Electrical Energy consumption (kWh) of a window air conditioner depends on several variables:

1. Cooling Capacity: The cooling capacity of the window unit is measured in British Thermal Units (BTUs). The higher the BTU rating, the more energy it typically consumes.
2. Efficiency: The efficiency of the window AC unit plays a vital role in energy consumption. Higher-efficiency units tend to use less electricity to produce the same amount of cooling.
3. Insulation Quality: The quality of insulation in your home (or vehicle) affects the amount of heat that enters or escapes, thus impacting the workload on your AC unit.
4. Ambient Temperature: The temperature of the surrounding environment also affects energy consumption. The hotter the temperature, the harder the AC unit has to work to maintain a cool indoor climate.
5. Usage Duration: The number of hours you run the AC unit daily directly influences the energy consumption.

Considering these factors, it becomes clear that providing a general and exact answer to the question, “How much energy does a window AC use?” is challenging.

However, by eliminating some of these variables, we can estimate the energy consumption of a window ac based on its cooling capacity (BTU rating), efficiency, and usage duration (hours).

Additionally, if we take into consideration the electricity prices in your area, we can also estimate how much it would cost to run your window air conditioner.

To simplify this process, you’ll find a calculator that estimates the costs of running your air conditioner based on its cooling capacity, its daily usage duration, and the location of the air conditioner.

Once we’ve covered that, I will also discuss other important aspects related to your window air conditioner’s electricity usage, including voltage, amperage, and wattage. Understanding these aspects is essential for selecting the appropriate equipment, such as an inverter or generator, to power your window AC unit efficiently.

Let’s get into it.

## How much energy (kWh) does a window ac use?

As explained above, Electrical Energy represents the actual quantity of electricity consumed over a certain period of time and is commonly measured in kWh (kiloWatt-hours).

A window AC can use anywhere from 0.3 kWh and 2.5 kWh of energy per hour, depending mainly on the cooling capacity of the air conditioner, and its energy efficiency.

For instance, a 5000 BTU window AC unit, on average, consumes around 0.3 to 0.4 kWh of energy per hour. In contrast, a more powerful 14000 BTU window unit can use between 0.8 and 1.2 kWh of energy per hour.

To give you a better understanding, here’s a table that estimates the hourly energy consumption (kWh/hour) of window AC units based on their BTU ratings. Additionally, it provides an estimate of their monthly energy consumption (kWh/month) assuming 8 hours of daily usage:

These estimates should provide a general perspective, but keep in mind that they are rough approximations.

You can actually get your own estimates using the capacity and efficiency ratings of your window air conditioner. Let me explain.

An air conditioner’s capacity to cool air is conventionally measured in BTUs (British Thermal Units). However, 2 window units with the same cooling capacity might require different amounts of energy to achieve the same level of cooling.

EER, or Energy Efficiency Ratio, is used to measure the ratio between an air conditioner’s capacity to perform heat exchange and the amount of energy that it consumes performing it.

For example, if a 10000 BTU air conditioner requires 1000 Watt-hours (Wh) of energy to remove 10000 BTUs of heat in an hour, it could be said that the air conditioner has an EER of 10:

EER = BTUs removed ÷ Watt-hours consumed

EER = 10000 BTUs removed ÷ 1000 Wh consumed

EER = 10

Reversibly, if you know the capacity of your window AC in BTUs, and its rated EER, you can easily estimate the hourly energy consumption of the unit:

Hourly Energy Consumption (Watt-hours per hour)= BTUs ÷ EER

Both the BTU and EER ratings of your window air conditioner are usually specified by the manufacturer on the EnergyGuide label that comes with the unit.

For example, here’s an EnergyGuide label from a 10000 BTU window unit:

With an EER of 11, the energy consumption of this 10000 BTU unit can be estimated as such:

Hourly Energy Consumption (Watt-hours per hour) = BTUs ÷ EER

Hourly Energy Consumption (Watt-hours per hour) = 10000 ÷ 11

Hourly Energy Consumption (Watt-hours per hour) = 909 Wh/hour

to convert this energy consumption figure from Watt-hours (Wh) to kiloWatt-hours (kWh), we’ll simply divide by 1000:

Hourly Energy Consumption (kiloWatt-hours per hour) = 909 Watts ÷ 1000

Hourly Energy Consumption (kiloWatt-hours per hour) = 0.9 kWh/hour

For a more accurate measurement of your window AC’s energy consumption, you can always use an electricity monitoring device like the Kill-A-Watt meter.

Simply plug it in between the electrical outlet and your unit, and it will accurately measure the energy usage over a specific timeframe.

Once you’ve determined the energy consumption (kWh) of your window AC, calculating the cost of running it becomes a straightforward task.

## How much does it cost to run a window air conditioner?

Determining the cost of running a window air conditioner depends on its electricity consumption rate (kWh/hour) and the electricity prices in your area (cents/kWh). On average, a window AC unit can use anywhere from 3 cents to 60 cents of electricity per hour.

Monthly costs for running a window air conditioner will also vary based on your usage patterns.

To give you an initial idea, here’s a table that categorizes window AC units by their BTU ratings and estimates the hourly and monthly costs assuming an 8-hour daily usage:

Please note that these estimates are based on the national average cost per kWh provided by the U.S. Energy Information Administration (EIA) in April 2023. The actual cost per kWh may vary by state.

For a more accurate estimation, I recommend using an electricity monitoring device to measure the actual energy consumption of your window AC unit and factor in the specific cost per kWh in your area.

To calculate the hourly cost of running your window AC:

Hourly Cost To Run Your Window AC (Cents) = Hourly Energy Consumption Of Your Window AC (kWh) x Electricity Costs In Your Area (Cents)

To calculate the monthly cost of running your window AC:

Monthly Cost To Run Your Window AC (\$) = Monthly Energy Consumption Of Your Window AC (kWh) x Electricity Costs In Your Area (\$)

For example, let’s say you’d like to estimate the monthly cost to run a 10000 BTU Window AC. And, let’s assume the following:

• You’ve monitored the energy consumption of the window unit over a 24-hour period and determined that it uses 1.2 kWh per day:
• You live in the state of Florida

The monthly energy consumption of the window air conditioner can be calculated as such:

Monthly Energy Consumption (kWh) = Daily Energy Consumption (kWh/day) x 30 days

Monthly Energy Consumption (kWh) = 1.2 kWh/day x 30 days

Monthly Energy Consumption (kWh) = 36 kWh/month

According to the June 2023 data from the EIA1 kWh of energy costs 15.36 Cents in Florida. The monthly cost to run the window air conditioner can be estimated as such:

Monthly Cost To Run Your Air Conditioner (Cents) = Monthly Energy Consumption Of Your Window Air Conditioner (kWh) x Electricity Costs In Your Area

Monthly Cost To Run Your Air Conditioner (Cents) = 36 kWh x 15.36 Cents/kWh

Monthly Cost To Run Your Air Conditioner (Cents) = 553 Cents

Monthly Cost To Run Your Air Conditioner (\$) = \$5.53 /month

If you don’t have an electricity monitoring device, you can use our calculator below to estimate the cost of running your window air conditioner based on its capacity (BTUs), your daily usage, and your location:

Now that we’ve got that out of the way, let’s discuss the other electrical specifications of your window AC that you might want to know about.

## How much electricity does a window AC use?

Other than the electrical energy consumption of your window air conditioner, which is the actual quantity of electricity that your AC unit consumes over a certain period of time, there are 3 other main electrical ratings that will characterize it:

• Its Voltage, measured in Volts and symbolized by the letter “V
• Its Electrical Current usage (Amperage or Amp draw), measured in Amps and symbolized by the letter “A
• And most importantly, its Electrical Power usage (Wattage), measured in Watts and symbolized by the letter “W

The relationship between these aspects of electricity, including the energy consumption of the AC unit, can be represented via a couple of formulas:

1- Power Usage (Watts) = Voltage (Volts) x Amperage (Amps)

2- Energy Consumption (Watt-hours) = Power Usage (Watts) x Usage Duration (Hours)

3- Energy Consumption (kiloWatt-hours) = Energy Consumption (Watt-hours) ÷ 1000

In other words, determining the Voltage, Amperage, and Wattage of your window air conditioner is not only useful when sizing equipment, but can also help you estimate the energy consumption of your window unit, and therefore, how much it costs to run it.

First things first.

### Window air conditioner voltage:

In the U.S., most appliances run on the standard 110-120 Volts that you would find in a regular wall outlet. This applies to window AC units and most other types of air conditioners, except for larger units, which sometimes run on a dedicated 220-240 Volts circuit.

For example, the following image is from the electrical specification label on a 5000 BTU window air conditioner:

In the image, you can see that the manufacturer specifies “115V-60HZ 1PH”, which translates to 1150 Volts/60 Hertz (frequency)/single phase.

Now, if you’re planning to run your window ac unit on batteries, or a combination of solar panels and batteries, you’ll require an inverter. When sizing the inverter, one of the key specifications to look at will be the output voltage of the inverter, which has to match the Voltage usage of your window air conditioner.

For example, to run this particular 5000 BTU window air conditioner on an inverter, the inverter has to have an output Voltage rating of 110-120 Volts.

### How many amps does a window AC use?

At a standard voltage of 110-120 Volts, a window AC unit can draw anywhere from 3.5 to 25 Amps of current. The exact amp draw of a window air conditioner will depend on the cooling capacity of the unit (in BTUs), the voltage of the unit, and its efficiency.

If we consider a standard Voltage of 115 Volts, the following table estimates the current usage (amps) of window air conditioners based on their cooling capacity (BTU rating):

The exact amperage of your window AC unit is usually specified by the manufacturer under “Amps”, “Amperage”, “Current”, “A”, or something similar. This specification is usually specified on a spec label on the unit, or in the documentation.

For example, let’s look at the specification label on the 5000 BTU window AC unit from our previous example:

The manufacturer specified that this 5000 BTU unit uses approximately 4 Amps of current.

Now that we’ve discussed Volts and Amps, let’s discuss the product of the two: Watts.

### How many watts does a window AC use?

A window AC unit can use anywhere between 400 and 3000 Watts of power. The exact power usage of a window air conditioner, or how many watts it uses, will mainly depend on its cooling capacity (its BTU rating), but will also depend on the efficiency of the unit (its EER, SEER, or CEER).

However, to provide some perspective, here’s a table that estimates the power usage (Wattage) of window AC units based on their BTU ratings:

Specified as “Watts”, “Power”, “Wattage” or similar, the exact power usage of your window air conditioner can also be found on the specification label on the unit, or in the documentation.

If we look at the specification label from the 5000 BTU AC unit from the previous examples, you can see that the manufacturer specifies 455 Watts as the power usage of the unit:

However, in some cases, the exact power usage of the window unit is not directly specified. In such a case, the wattage can be determined using the Power formula mentioned above:

Power Usage (Watts) = Voltage (Volts) x Amperage (Amps)

For example, with 4 Amps as the Amperage of the unit, and 115 Volts as its Voltage, the Power usage of the unit can be calculated as such:

Power Usage (Watts) = Voltage (Volts) x Amperage (Amps)

Power Usage (Watts) = 115 Volts x 4 Amps

Power Usage (Watts) = 460 Watts

Notice that there’s a slight difference (about 5 Watts) between the specified, and the calculated power usage of the unit. This is not an issue.

The Amperage, the Voltage, and the Power usage of the unit will actually slightly vary during usage, so, none of the electrical specifications provided by the manufacturer are 100% exact, to begin with.

Determining the Power usage of your window AC unit is also important when trying to determine the appropriate equipment that can run it.

For example, one of the main specifications to consider when sizing an inverter that can run your air conditioner is the continuous power rating of the inverter, which has to be greater than the power usage of your window air conditioner.

More on this topic here.