How Long To Wait Before Turning On Air Conditioner? [Solved!]

I still remember that my mom asked me to let it settle for a day when I got my first air conditioner. Despite the fact that I didn’t understand why at the time, I decided to take her advice.

In many cases, you need to allow your AC to settle before turning it on. But how long should you wait? 

It depends. Some models can start to work immediately (some new generations), whereas some models should wait for up to 24 hours before turning it on. Following the guidelines in the manual is your best bet, but 24 hours should be enough for most air conditioners.

Please continue reading if you don’t understand why you should let it settle and if you must wait in certain situations, such as after moving or cleaning. In this post, I’ll go over everything important.

Why should you let an air conditioner settle?

Many people may have heard that they should wait before turning on their air conditioning unit, but not everyone understands why. 

In fact, not only air conditioners but dehumidifiers and refrigerators are required to do it as well. 

This is because these devices rely on a compressor to function. The compressor is responsible for turning the refrigerant from gas to liquid and vice versa. Via this process, the device can cool down the air.

The compressor unit is made up of numerous small parts that require oil to lubricate. Otherwise, it may result in increased wear and tear or even system failure.

Because of transportation or incorrect placement, the oil may displace and take some time to settle back to the bottom of the compressor. As a result, your air conditioner must sit for a while before it can function.

Furthermore, the refrigerant must settle, which will take only a few minutes.

Don’t be too concerned if you just turn on your machine without letting it settle. It would not cause serious problems in most cases. But you should turn it off now and let it settle again.

How long to wait before turning on a new air conditioner?

How Long To Wait Before Turning On new Air Conditioner

The amount of time you must wait is determined by a variety of factors, including how your device is transported and the type and design of your AC.

The most straightforward way is to follow the guideline in the instruction manual, which should be in the package. You can also get the information on their official sites. 

On average, you should wait 8 hours to 24 hours before turning on your brand-new air conditioner.

Technically, you can save some time if your machine is transported in an upright position. But since you don’t know what happened during the transportation, it’s better to follow the instruction.

Window AC

Many people prefer window air conditioners because they are powerful, take up little space, and are simple to install. Allowing it to sit for 24 hours before use should suffice for most models.

Central AC

Since the Central AC system needs to be installed by HVAC professionals, they will tell you how long to wait. Based on my own experience, 24 hours is the advice they give to me.

Split AC

The compressor of a split AC is located outside, which is similar to a central AC. In general, you should let it settle for 12 to 24 hours after installation.

Portable AC 

Usually, portable air conditioners take less time to settle. Compared to other types, they only need 8 to 10 hours.

All in all, when deciding how long to wait before turning on your new AC, following the guideline of the manufacturer is the best choice. Alternatively, allow your appliance to settle for 24 hours. 

How long to let an air conditioner settle after moving?

Whatever the reason, you may need to relocate your air conditioner at some point. For instance, if you have a portable air conditioner, you might want to move it from your living room to your bedroom at night.

The time it takes for the AC to settle after moving is determined by how you move it. You don’t need to let the machine settle if it stays upright during the process.

You should, however, wait a few hours if the machine is tilted during the process. Again, 24 hours is sufficient to ensure that your AC is completely safe.

As a result, those who intend to use their AC immediately should proceed with caution when moving it.

How long to wait if your AC hasn’t been used for months?

If your air conditioner has been sitting for months, it does not require additional time to settle before turning on because it is upright and all of the oils are in the compressor.

However, cleaning your machine and inspecting the damage before restarting it is recommended.

However, storing it in other locations can make things a little more complicated. If you store it upright, there is no need to wait. If you place it on this side, it should sit for about 24 hours before activation.

How long to wait to turn on AC after cleaning?

For better performance, you need to clean the coils and filters every so often. After cleaning, don’t turn on your AC immediately. Please wait for a few hours until the coils and filters are dry. On hot days, it may only take one hour.

How long to wait after an AC recharge?

You don’t need to move your AC unit when recharging. Hence, the oil in the compressor will not displace. However, it doesn’t mean it doesn’t require settling.

As I mentioned above, the refrigerant (Freon) also needs to be settled. An AC recharge will take around 30 minutes to 1 hour; after that, you need to allow it to sit for a few minutes.


Because air conditioners require oil and refrigerant to function, you must ensure that these substances remain in their proper locations. Your machine will be damaged and may even fail if they become displaced.

As a result, in some cases, allowing your machine to settle is critical.

If you can’t find the information in the manual, a good rule of thumb for new air conditioners is to sit upright for 24 hours.

When moving it from here to there, please keep it upright. Otherwise, you must wait a few hours before restarting.

It is also critical to store your air conditioner upright. It enables you to activate it immediately.

Beyond that, remember to wait for a few minutes after recharge.

About The Author

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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 dozens 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.

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