Do Air Conditioners Dehumidify? How to Reduce Humidity using Your AC

No one likes high humidity. It can be super uncomfortable and makes us sweat. And if the humidity level in a house won’t decrease, our sweat won’t evaporate either! So in this post, I go over how central ACs, as well as portable, and Window Unit ACs, dehumidify as well as the difference in humidity levels each provides.

So the quick answer is YES, ACs do dehumidify but to what level is different in central, portable, and window units. Depending on the amount of humidity you are dealing with, choosing the right type of AC will be crucial to your overall comfort as well as preventing issues that high humidity can cause inside a home.

During summer most states experience a brutal combination of heat and humidity. This not only affects indoor air quality and comfort but also accelerates the growth of mold and mildew in a home. This is the time an air conditioner becomes useful to use.

The primary role of an AC unit is to cool air, but it can also do a good job of lowering the high levels of humidity. However, extreme levels of humidity will put a strain on even the most powerful air conditioning system, and running a dedicated dehumidifier may be the only way of getting rid of that sticky hot air in your home.

How do Air Conditioners Dehumidify?

How do Air Conditioners Dehumidify?

Removal of water from air serves as a byproduct of air cooling by modern air conditioning systems. When the AC unit draws in hot air and passes it over coils filled with refrigerant, the water vapor available in the air will also condense on the coils and eventually drain away into the drip pan.

However, too much water condensing on the coils will affect how your air conditioner work. First of all, your portable air conditioner will fill with water quickly. This results from a reduced airflow around the condensation coils which can also cause the compressor to fail. You will then realize that your air conditioner is not cooling and you may need to contact an HVAC professional to get you sorted out.

Do you need a dehumidifier if you have an AC unit?

In normal weather, an AC unit is enough to control your indoor humidity and temperature. In humid subtropical climates found in American Gulf and lower East Coast states, you will need a dehumidifier to keep indoor humidity in check even when having an AC unit installed in your home or property.

Too much humidity can cause mold growth

An increased level of humidity does more harm than just making you uncomfortable. This is a favorite media for the growth of mold and mildew whose spores cause serious respiratory infections. High levels of water in the air will also damage your water-sensitive surfaces, carpets, and fabrics.

Untreated wooden floors, furniture, and fittings warp or rot when persistently subjected to higher moisture contents. The same also catalyzes the formation of rust on your metal surfaces and items including electronics. A good dehumidifier will put a stop to all these problems.

Air Conditioner Dehumidifier Mode – How it Works

Dry mode is a feature available in some types of air conditioning units. When selected, it makes an air conditioner to efficiently reduce humidity in the room. Air conditioner dehumidifier mode is a great energy-efficient function that will reduce your power costs and lower your carbon footprint as well.

Standard cool-mode is the normal setting for removing heat from the air. When the weather changes to humid, using the same function isn’t energy efficient. Cool mode is great to use when both the room temperature and the humidity levels are excessively high.

In dehumidifier mode, the air conditioner isn’t really releasing cold air, nor actively cooling the room. Moisture is only removed from that particular air before it exits the unit to flow back into the room. This means that the fan and the other inner parts of the AC unit will be running, but it won’t blow out any cold air.

AC Dehumidifier Mode

When to use air conditioner dehumidifier mode

  • The temperature in a room is cool, but the humidity is high
  • You need to conserve electricity and lower your bills
  • You don’t want the air in your room to be too chilly
  • It’s the cooler months of the year or humid rainy seasons

Do Window AC Units Reduce Humidity?

Do Window AC Units Reduce Humidity?

Yes, window AC units do reduce humidity! But sometimes an AC CAN make your room humid as well, due to certain issues within the unit.

In this section, I’ll explain how a window AC can reduce the humidity level inside your room, along with some simple solutions to lower the humidity level if your air conditioner contributes to its increase.

Do Window Units Control Humidity?

Yes, most window ac units come with a dehumidifying feature. You can check for this feature by going through AC’s specification sheet. 

However, this feature does not work as effectively as a dehumidifier, since it’s not AC’s main purpose. As with any ac, a window ac consists of a compressor, thermostat, evaporate and condenser coils, a fan, and tubes filled with a refrigerant (liquid/gas). 

When the ac is turned on, and the temperature increases, the thermostat detects this and turns on the fan in the ac unit. The fan pulls the air in the room into the unit, where it goes over the cold coils (evaporator coils). As they go over the moisture, the air is condensed on the cold coils, which are then drained through the hose or evaporated and collected at the bottom of the unit. 

 As it happens, the room’s humidity (moisture in the air) level falls to a certain percentage.

How Much Humidity Do Window ACs Remove?

How Much Humidity Do Window ACs Remove?

The amount of humidity expelled is measured by Pints per hour (Pt/h); the dehumidification rate can differ from one brand to another. 

These details can be found under the dehumidifying feature, in the specification sheet. 

Depending on the dehumidification rate, an average window AC can remove 5 to 20 gallons of water from the air in your room per day. 

The size and the type of the room, the size of the window AC, and the position of how it is installed all depend on the changing percentage of the humidity level in your room, so it is necessary to consider these factors.

Reasons Why A Window AC Would Make A Room Humid?

There are several reasons why an AC would make your room humid, some of these are:

Evaporating Coils Have Accumulated Dirt

One reason can be that the evaporating coils have accumulated dirt. So even though it does its function, it is not as effective as it was before, and now the humidity is not removed properly. Carefully cleaning these coils can solve the issue.

Oversized Window AC

Another reason can be due to an oversized window AC, which causes short cycling. When the cycles are short, it doesn’t follow the full refrigerant cycle which results in the set temperature being reached quickly. 

This makes it unable to collect moisture from the air. The solution is to replace the oversized AC with a smaller window AC, which is suitable for the room.

Leaving the AC at the ON Setting

Another possibility is leaving the AC on the ON setting, which can also increase the humidity; the on setting tells the fan to constantly keep working. When the fan is continuously working, it can release the condensed water from the coils (condenser coil) back into the room. 

So even though it cools it won’t remove the moisture. Selecting the auto setting instead of the on setting can fix this issue.

How To Lower the Humidity in a House

Exploring other ways of lowering the humidity in the house can save you the burden of installing two heavy power-consuming air systems – a dehumidifier and an air conditioner. The following ways of preventing moisture build-up in your home will significantly lower the level of humidity.

1. Run exhaust fans in your home

Kitchen and bathroom usage greatly increase moisture content in the air. Running externally venting exhaust fans when cooking and taking shower will drive away excess water vapor and odors.

2. Grow plants that absorb humidity

Some thirsty plants are capable of absorbing water vapor from the air thus lowering the humidity levels. Plants that absorb humidity will also add color to your décor, reduce carbon dioxide gases and provide refreshing air.

3. Regularly clean AC filters

Filters are important parts of HVAC systems. With time, filters become dirty and without proper cleaning, they will be clogged. This will stop air from passing through them and you will no longer enjoy the desired comfort. Normalize cleaning and replacing air conditioner filters as needed.

4. Dry your clothes outside

Laundry activities can raise the level of humidity in a home. One popular behavior is hanging clothes inside, which contributes to more water vapor in the air. Letting your clothes dry outside after washing them will prevent moisture build up in the air inside your home.

5. Take cold and short showers

Hot showers are enjoyable but they contribute to increased water vapor in a home. Taking colder and short showers not only saves on power costs but also cut humidity levels.

How To Reduce Humidity Levels in A Room

There are several things which you can do to reduce the humidity level of your room since it is very essential in the summer:

  • Getting AC to your room is the obvious choice you can pick since it not only decreases the humidity level but also cools your room.
  • Using a dehumidifier is also an option since it removes moisture from the air. The dehumidifier also reduces the usage of an air conditioner, which means less electric bills; because dehumidifiers use less electricity than air conditioners.
  • Opening the windows can also reduce the humidity of the room but this is not necessary if the air conditioner or dehumidifier is working. Keeping the window open can also bring uninvited pests into your room.
  • Indoor plants (except Boston ferns which remove the moisture from the air) can increase the humidity, so placing them outside or in a well-air-ventilated room will reduce the humidity level. The same goes for drying clothes inside your room. If so, take them outside or change rooms.
  • Maintaining a proper ventilation system where moisture air can exit from the house will keep the humidity level down. Drying wet surfaces before they evaporate and accumulate with air can also reduce the humidity level.


Do Air Conditioners on Heat Dry the Air?

No, when the air conditioner is set to heat mode the condensation in the coils does not happen so it will not remove the moisture in the air, leaving your room moisturized.

Will a Window Air Conditioner Dehumidify a Room?

Yes, a window AC can dehumidify a room to a certain level, when the moisture from the air is condensed in the evaporating coils, and the water dripping from the coils is drained out of the room.

Final Thought

Both high and low levels of humidity is not good. Use a hygrometer to measure humidity levels especially when you live in subtropical regions or you are not experiencing your indoor desired comfort. While an air conditioner will help in correcting humidity in normal climates, higher levels will need a dehumidifier – which is less expensive than AC unit and uses less power.

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