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Can You Plug an Air Conditioner Into an Extension Cord?

Written by Edwin Jones / Fact checked by Andrew Wright

can you plug an air conditioner into an extension cord

Extension cords are temporary solutions to power appliances when outlets are too far away. They can be safe when used according to their rating but dangerous when not used right.

A debatable use of extension cords is with air conditioners, especially when air conditioners are used in rented apartments.

So can you plug an air conditioner into an extension cord, and should you even consider it? While extension cords sometimes help, they generally should not be used with ACs.

Is It Safe to Plug an AC Into Extension Cord?


The first reason why we generally should not plug an AC unit into an extension cord is the air conditioner’s motor. An air conditioner uses a motor that will draw the maximum load it can to start the compressor.

However, extension cords can cause a voltage drop that either causes the motor to stall or draw more current. This, in turn, generates more heat and can damage the motor in the long run.

Hence, the installation of air conditioners must always be planned with their cables in mind. The outlets of air conditioners should be close to the units, and a certified electrician can help set up new outlets if needed so that extensions aren’t necessary.

This way, you won’t need to worry about having an AC cord too short of reaching the socket.

Another way to ensure air conditioners get enough energy is by making conductors short and thick.

Shorter cords have less resistance (and therefore lower voltage drops) than longer cords, while thicker cords allow more current to reach the unit. Combine such cables with a grounded socket, and your AC on the extension cord will run more safely.

How Many Currents Do AC Units Draw?


The second reason to avoid using an extension cord for an AC is the latter’s continuous load.

Different AC units will draw different amounts of current, depending on their rating. A 12,000 BTU air conditioner can draw 8.7 amps to 13 amps of current, while a 14000 BTU unit can draw an average of 12 amps, depending on its EER.

If the unit runs for as much as 3 hours, it will draw a significant amount of current during its operations.

When connecting extension cords to AC units, the high amount of current flowing through them may cause the extension cord to heat up. The longer the cable, the more heat it will generate, leading to fires and property damage.

How to Safely Use Extension Cords for AC Units

We do not recommend extension cords for AC units. However, if you must use them, consider the following tips.

Extension cords should be temporary.

Extension cords should only be used as temporary connections. Do not mount or fix them on surfaces and do not hide them within the floor or ceiling. Also, avoid placing them under carpets.

A permanent outlet should be installed near the location where the AC will be installed. Talk to a certified electrician who can do this.

Use an appropriate extension cord for AC units.

  • Use an extension cord that is long enough to reach the outlet. Remember, the longer the extension cord, the larger the resistance, so if the AC unit is only 10ft away, avoid using a 20 ft extension cord.
  • Extension cords for window air conditioners are available at hardware stores. They can be medium duty or heavy duty extension cord that can handle the current flows needed by AC units. They can also be 120V or 220V extension cord.
  • Choose the right cable based on the current draw of the air conditioner. Always check your appliance manual for this rating. 12 gauge is good for up to 15 amps at 100 feet.
  • As much as possible, use a dedicated extension cord for the AC unit. Some stores might sell an air conditioner power strip that has more outlets than necessary, which can pull more current when another appliance is plugged into the strip while the AC unit is running.

If you’re interested in further insights, Reddit has also been discussing this question. Participate in the dialogue here:

Is it safe to use this extension cord, with my portable A/C, plugged into a bathroom 20amp breaker?
byu/DaddySanctus inelectrical

Frequently Asked Questions


What is the gauge extension cord best for AC?

A 12-gauge extension cord is good for up to 15 amps and up to 100 feet. Consider a thicker one when the manual states higher current for the air conditioner unit. 10-gauge wires, for instance, will handle up to 20 amps at 100 feet.

What kind of extension cord can I use for an air conditioner?

Use an extension cord with a short length and a low gauge. These are available in hardware stores. Not all extension cords are meant for high powered, continuous loads like air conditioners.

Can I use a portable air conditioner instead of window air conditioner?

From an electrical safety standpoint, portable units are fine alternatives to window air conditioners that are far away from outlets. They can be moved towards the closest outlet while their exhausts can be mounted to the window.

However, they are less efficient than window air conditioners due to the presence of an exhaust hose: This hose is necessary to move air from inside the home to the outside and vice versa, but it is also inefficient because some of the heat may escape and go back inside the room.


Can you plug an air conditioner into an extension cord? Generally, you should avoid doing so. Only use an extension cord with an air conditioner as a temporary measure; a permanent outlet is the better choice.

If an extension cord is really needed, always remember to use the shortest cable possible and size it based on the current rating of the AC unit.

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