Do You Know When to Use Dehumidifier with Air Conditioner? Find Out Here!

When you have cooled the indoor air but it still feels sticky, turn on the dehumidification mode on the air conditioner. It will help to lower the humidity level indoors. 

Indoor humidity should be between 30 and 55 percent. Some resources say 30 to 50%; others say 40 to 60 percent. Just don’t do 70 percent humidity as that is too high indoors.

And they are all right!

You see, the relative humidity level that you should set for your home mostly depends on the temperature.

In winter, you might need to set a slightly higher humidity level than you would in summer.

But I digress…

In another article, we asked whether you can use a dehumidifier instead of an air conditioner, and we saw that you cannot. You see, while a dehumidifier has a cooling effect, it is minimal; it does not affect high temperatures.

And that is what brings us to this article.

If the indoor temperature is high, you need to use an air conditioner to bring it down since a dehumidifier blows hot air to the recommended level of 68 to 78 degrees Fahrenheit (20 to 26 degrees Celsius).

Should you run a dehumidifier and air conditioner at the same time?

Yes, you should, if the humidity and temperature are too high. For instance, in the summer, a place like Florida is going to experience high humidity levels. It will also be super hot, both indoors and outdoors.

Thus, the only thing that makes sense is to lower the temperature with an air conditioner and lower the humidity with a dehumidifier. High humidity will cause the development of mold.

If your indoor temperature rises above 78 degrees Fahrenheit (26 degrees Celsius), you will not be comfortable. Actually, it is better to keep it between 22 and 25 degrees Celsius.

If your indoor humidity is above 55 percent, you will not be comfortable. It will also cause mold in the bathroom, basement, kitchen, closet, and other warm and moist spaces.

Thus, if you have been asking when to use a dehumidifier with an air conditioner, it is when the indoor heat and air moisture levels exceed the parameters I have shown you above.

Read: Temperature and humidity relationship chart

Will running a dehumidifier help the air conditioner?

Running a dehumidifier helps your air conditioner. There is a reason for saying that.

For instance, humid air is harder to cool than dry air in the house. Thus, when the humidity is too high, the air conditioner will have to work super hard to make the air cooler.

Since your air conditioner uses electricity to cool your home when it has to work extra hard, it racks up the power bill, so you have to pay more money at the end of the month.

Also, an air conditioner is designed with plastic as well as metal and electrical parts. If there is too high humidity, it is not good for the health of the metal and electrical parts.

Read: How To Stop Humidifier White Dust

They will start to corrode, and this is going to shorten the lifespan of the appliance. To avoid this, you need to reduce the humidity to the recommended indoor levels.

When you run a dehumidifier, it will help to make the air conditioner more efficient. Thus, it will cool a room faster than it would with high humidity.

You run an air conditioner to keep your rooms comfortable and warm. However, even if you lower the temperature in your home, if the humidity is too high, it will still be uncomfortable.

When it comes to indoor temperature and humidity, you cannot lower one and ignore the other. You have to address both conditions.

Air conditioner with a dehumidifier mode

What is the dehumidifier mode in AC? This is a mode or a setting that portable air conditioners come with. By design, the air conditioner has cold coils, which act in the same way as the dehumidifier coils.

These coils attract the water vapor in the air, cool it, and cause it to condense. This effectively reduces the humidity level in your house.

At the same time, it does not take too much energy to do this since the fan will be running at a low, constant speed.

Also read: What is the brown stuff in my humidifier

However, please note that for places like Seattle with high humidity, the dehumidification mode on the air conditioner might not help much, especially in the summer. Thus, it is best to get a dehumidifier.

When should I run my AC in dry mode?

If your portable air conditioning unit already has dehumidification mode, when should you run it? It is also called dry mode. You should turn this on when the air temperature is not high, but the air still feels sticky.

Image of do air conditioners remove humidity

Air conditioners have different settings, and by the way, this applies to both whole house and single, portable units.

For instance, there are cool and dry functions, which are used for different weather conditions. When the indoor temperature is too high, exceeding 25 degrees Celsius, you can use the cool function to lower it.

Also read: Why Does My Dehumidifier Blow Cold Air?

Lowering the temperature does not lower the humidity. When your hygrometer shows you that the indoor humidity is high, you need to use the dry mode on the air conditioner. It lowers the moisture content of the air.

When To Use Dehumidifier with Air Conditioner FAQ

According to, an average American home has 17.5 appliances for a family of 6 or more people. You can be sure that among these appliances, there are humidifiers, dehumidifiers, air conditioners, air purifiers, and many others.

Surprisingly, most people do not know when to use comfort appliances such as dehumidifiers, or air purifiers and air conditioners. This FAQ section will help you learn more about when to use a dehumidifier with an air conditioner.

Do air conditioners dehumidify?

Yes, they do, albeit with just a small margin. Most of the air conditioners in the market today come with a dehumidification mode.

Using this mode gets the coils to start attracting the water vapor in the air, lowering humidity when the temperature is not too high.

What does a dehumidifier do on an air conditioner?

Using a dehumidifier with an air conditioner makes the latter more efficient at its job. In high humidity, air conditioners have to work extra hard, and that spikes the electricity bill. It also shortens the lifespan of the air conditioner.

What is dehum mode on the air conditioner?

This is also called dehumidification mode, which most modern portable air conditioners come with. When the indoor temperature is low, but the air in the room still feels sticky, you turn on the dehum mode, which helps to lower the humidity.

Do you need a humidifier when you have air conditioning?

This depends on the weather conditions of the place you live. In places like Australia, you need a humidifier, a dehumidifier, and an air conditioner.

If you experience hot and dry summers, you need to use a humidifier in summer, and you need the AC to lower the temperature.

Final Thoughts

After reading this write-up, you now know when to use a dehumidifier with an air conditioner. When the AC cools down the air but it still feels sticky, you need to turn the dehum mode on. That is how an air conditioner helps with humidity.

It is perfectly okay to run a dehumidifier at the same time as the AC. Of course, this is going to rack up your power bill, but hey, it will make your indoor living space comfortable.

Besides, you can use the dehumidifier water to water your plants!