Extension Cord For Window AC: Can You Use It & How To Do It?

Liz Yang

When it comes to using household appliances, safety is always the top priority. Because not every window has an outlet nearby, the simplest way to power your window air conditioner is with an extension cord.

But can you plug a window AC into an extension cord? While it is not recommended to do that, you can use it temporarily as long as the extension cord is heavy-duty and capable of handling the current drawn by your machine. A 12-gauge extension cord could be a suitable choice for most models.

But there’s more than that. Let’s take a closer look at how to choose a proper extension cord for your window AC and what you should keep in mind while using it.

Can you use an extension cord with a window air conditioner?

Yes, you can use an extension cord with your window air conditioner unit, but it is only for temporary use.

This is because, when compared to connecting to an outlet, the extension cord is more prone to overheating and catching fire. Things will get even worse if you use it on a hot summer day.

In addition to that, doing this may void the manufacturer’s warranty.

So, even if it will cost you some money upfront, installing a new outlet near your window AC is always your best bet.

Can you use a regular extension cord with a window air conditioner?

While plugging your window AC into an extension cord is not likely to cause any serious problems immediately, it doesn’t mean that every regular extension cord at home can be used for it.

This is because a window air conditioner needs much more power than a regular small gadget. Regular extension cords are often rated for 8A or 10A devices, which is inadequate for your AC.

When you connect your AC to an undersized extension cord, it will work hard to draw electrical current, resulting in overheating, a short circuit, a meltdown, or a fire.

So you shouldn’t use the regular extension cord at home if you are not sure how many amperes of current it can handle.

What extension cord do I need for a window AC?

Given that a standard extension cord cannot be connected to a window AC, let’s look at how to select the best one for your machine.

Calculate the current your window AC uses

Typically, you can’t find how many amps your window AC uses on the label, but this value is a good way to judge whether or not the extension cord can handle your AC. 

Since current equals wattage divided by voltage, you can know the current your AC needs as long as you know the wattage value. Luckily, you can find it on the label or in the instruction manual. 

On average, the power a window AC can use ranges from 450 to 1500 watts. Because the voltage in the US is about 120 volts, you can know that the current your window AC will draw is around 4 Amps to 14 Amps.

However, air conditioners use more power when they start up, so the extension cord must be able to handle amps greater than the result.

As a result, an extension cord rated at 20 amps or higher may be a good choice.

Wire gauge of extension cord 

The larger the extension cord, the higher the amperage rating it can deal with.

Wire gauge refers to the physical size of the wire. Contrary to popular belief, the larger the size, the smaller the number. A 12-gauge wire, for example, can carry up to 20 amps, whereas a 10-gauge wire can carry up to 30 amps.

That is to say, a 12-gauge extension cord, as well as any extension cord larger than that, should be adequate for your window air conditioner.

Extension cord length

The ideal cord length for a window air conditioner is approximately the distance between the outlet and your machine. An overly long cord can cause voltage drop and tangles. It is also vulnerable to damage.

The longer extension cord has more resistance, causing it to heat up and waste more energy.

If you don’t want to pay more on your electricity bill or start an electrical fire, use an extension cord that is not too long.

Three-prong extension cord

You window AC extension cord should be three-prong. This is important because it can protect your AC by preserving the ground connection whenever a power surge happens.

Additional safety tips for using an extension cord with a window AC

While choosing a proper extension cord is important, using it safely is also crucial. You should exercise caution while using it.

Connect the extension cord firmly with the outlet and window AC

When the connection is loose, the current encounters more resistance, which can cause the cord to overheat. As a result, make sure the connections on both ends of the extension cord are tight.

Unroll the extension cord 

The coiled extension cord is dangerous because it can’t adequately disperse heat generated inside, which may melt the plastic insulation and catch fire. So unrolling the cord is an important thing you should always keep in mind.

Don’t place it on the floor

If you leave the cord on the ground, it could become a tripping hazard. Furthermore, accidentally spoiled water can get into it, causing a short circuit. You should secure it to the top of the baseboard.

Keep it away from children and pets

Your small children and pets may not realize how dangerous it is to touch and play with an extension cord. They could become tangled and injured.

Wrapping up 

While installing another outlet is your best option, using a heavy-duty extension cord with your window AC temporarily is OK in most cases. 

You should make sure the extension cord is at least 12-gauge and not too long. A 10-gauge cord is a better bet.

Remember to unroll the cord, tighten the connection, and keep it away from pets and children.

Always use it with caution and have the outlet installed as soon as possible.

Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested a lot of products in person, like humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.