Does a Window Air Conditioner Need a Dedicated Circuit?

Window air conditioner units are often the most efficient and cost-effective tools to cool down a room in a home.

However, maintaining safe electrical practices and proper circuitry is the most important step in keeping a window air conditioner performing at its best. 

A window air conditioner unit will need its own dedicated circuit. While there are small units that do not require a dedicated circuit, these are rare. It is important to have a dedicated circuit so as to not cause an overload.

It is common to assume that most people these days have central heating and air in their homes, but this is not the case. It is important to know how to properly install window air conditioners.

Read on to better understand exactly what factors establish why your window air conditioner unit would need its own dedicated circuit. 

What Determines Whether a Window Air Conditioner Needs a Dedicated Circuit?

While some smaller window air conditioner units might not require their own dedicated circuits, the factors below will help you determine whether your specific circumstances call for a dedicated circuit. 

  • Size of the air conditioner unit
  • Electrical requirements of the air conditioner unit
  • Size of the room
  • Other appliances in the room
  • Any potential local building codes

Size of Unit and Electrical Requirements

The size and electrical requirements of a window air conditioner are the most important indicators of whether it will need a dedicated circuit. Larger air conditioners have high capacity compressors that require more electricity to operate. 

Most window air conditioner units are 110/120 volts. These air conditioner units that require 7 or more amps to operate will need their own dedicated circuits.

Smaller units that require fewer amps may not require their own circuits, but these units are not as common. 

If you do not have a dedicated air conditioner circuit, a professional electrician will need to install one for you. If your air conditioner unit requires a specific style of wall outlet, a professional electrician will need to install this type of outlet.

If a dedicated circuit was installed for a past unit, make sure it meets the requirements for any replacement unit you wish to install. This will prevent the need for an electrician to replace the old circuit with an entirely new one.

Size of Room

A larger room will require the air conditioner to do more work and use more power, pumping cool air into the space. While the size of the room often refers to the square footage, it also applies to the height of the ceiling.

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Rooms like bedrooms, living rooms, garages, and workshops are all great candidates for a window air conditioning unit. While these rooms vary in size, most of them are typically quite large.

Any window air conditioner units cooling these large spaces will require their own dedicated circuits to function properly.

Other Appliances

If there are any other major appliances in the room with the air conditioner, a dedicated circuit is necessary. An air conditioner already uses a great deal of power, and a second appliance is sure to overload the circuit

If you can be sure that the air conditioner will only ever have to share its circuit with something very small, like a desk lamp, a dedicated circuit may not be necessary.

However, this circumstance is exceptional, as many of us have several appliances in each room.

Computers, refrigerators, washing machines, and water heaters are examples of appliances that cannot share a circuit with your window air conditioner unit.

Building Codes

It is important to always consider local codes when building and installing items in your home. Some regions have specific building codes that include requirements for window air conditioner units.

Take these into account when determining whether your window air conditioner unit will need its own dedicated circuit. 

Potential Consequences of Not Having a Dedicated Circuit 

You might be wondering, “What’s the worst that could happen if I don’t have a dedicated circuit for my window air conditioner unit?” Well, if a window air conditioner needs its own circuit and does not have one, it could lead to negative results. 

Circuit Overload

First of all, a circuit is a loop through which electrical current flows to power an electric device. Every item that plugs into an outlet in your home requires a circuit to function.

Different circuits are built to produce different amounts of electric current, based on the kinds of items that will use the circuit.

When the items plugged into a circuit require more electricity than the circuit can produce, the circuit will become overloaded.

The breaker for that circuit will then flip, shutting off power to that circuit. All items on that circuit will immediately lose power. 

Circuit overloads do not always cause the breaker to flip, however. More annoying signs of a circuit overload include buzzing from electrical sockets and flickering lights.

A window air conditioner unit would not be suitable for a circuit that is powering multiple appliances. The circuit would not be able to provide enough electrical current and would get stuck in a perpetual overload cycle. 

Electrical Fires

If a home has faulty wiring, an overloaded circuit can lead to more serious consequences. For example, if a breaker does not flip and shut off the circuit like it’s supposed to, the heat could cause damage.

Excess heat from the overloaded circuit could melt the wiring, starting a fire. Insulation near the wiring can also catch fire easily.

Outlet covers could get too hot and melt, which would also act as potential fire starters. 

It is more common for these types of electrical house fires to occur in the winter when people are using heaters.

However, it is always better to err on the side of caution when installing any appliances that use a circuit, including window air conditioners. 

Cable Overuse

Some people try plugging their window air conditioner unit into an extension cord instead of into a proper dedicated circuit. This is not a good idea, as many extension cords are not rated for use with window air conditioner units.

Unless the extension cord is large enough for the job, plugging an appliance into the cord could cause electric shock.

Having excess cables around can also be a tripping hazard. If a window air conditioner is set up in a bedroom, likely, a person will occasionally walk around the room at night.

Large cables laid across the floor can cause trips and falls, which may result in serious injury.

It is always better to have a dedicated circuit than to use potentially dangerous or reckless shortcuts.

Installing a Window Air Conditioner with Dedicated Circuit

Now that you know your window air conditioner unit will likely require its own dedicated circuit, you are probably ready to begin cooling your rooms.

It is very important to have a professional electrician install a dedicated circuit for your air conditioner if one is not already available.

Before you plan on installing an air conditioner into your window, be sure the window can hold an air conditioner unit.

There are several types of windows, and your air conditioner unit will require a certain kind to work properly.

The window should not be in direct sunlight, or you will never get the full air conditioning benefits from the unit.

Have Help on Hand

Window units are heavy. It takes more than one person to install an air conditioner unit into a window; otherwise, there is great potential for personal injury or damage to the unit itself. 

Take Precise Measurements

Measure, measure, and measure again.

You will need to know the height and width of the window in which the air conditioner unit will sit, its tilt, and you will need to know the square footage of the room being cooled. 

Obtain Appropriate Accessories

Determine what accessories you will need and have them prepared. Mounting rails, side panels, and brackets are all available for certain window air conditioner units.

Depending on the size, weight, style, or brand of air conditioner unit you purchase, some of these items may be necessary for your setup.

L-brackets will most certainly come with your window air conditioner unit. These are crucial to ensure the window in which your unit sits will remain shut, and your unit will stay in place. 


Any home appliance can be overwhelming to install.

Window air conditioners can last for many years if installed properly and maintained. This starts with providing a dedicated circuit. 

It may seem expensive or inconvenient to pay an electrician to install a dedicated circuit in your home. It is well worth the cost, however. It will save money and stress in the long run.

A professional installation will aid in the prevention of potential fire damages down the road. It is a cool price to pay for peace of mind.