What Is Dry Mode on An Air Conditioner?

The Dry Mode or Dehumidifier Mode on an air conditioner dries the air without cooling it. Most AC types including central air conditioning, mini split systems and room ACs are now equipped to run a dry cycle that takes excess moisture out of the air without making the room uncomfortably chilly.

What Is Dry Mode on an Air Conditioner?

To start with, Dry Mode is different from Cool Mode. Here is the key difference: While Cool Mode or AC Mode is intended for removing excess heat, the dry function removes excess humidity. This means that the dry function does not cool a room but simply sucks in and releases the same air with reduced humidity – in short, it dries the air by removing humidity.

Yes, the natural function of the air conditioner is to also remove heat – but in Dry Mode, the heat removed is blown back into the room rather than being exhausted or carried out of the house. 

  • AC Mode removes heat and humidity
  • Dry Mode only removes heat

Does my AC have Dry Mode? If it is a newer unit, then it probably does have Dry Mode. Despite being a common feature on modern ducted and split-system ACs, Dry Mode is not on every unit. You will need to check your unit (or its remote control) for a “Dry” button or a water drop symbol. If you have either of these, your unit has a Dry Mode.

The Dry Mode feature works the same in portable air conditioner, window air conditioner and mini split systems. This is to say, once your set inside temperature is reached, the AC unit’s compressor and circulation fan maintain a lower speed while the exhaust fan runs at normal speed to remove humidity.  

Dry Model On AC

When Should I Run My AC in Dry Mode?

Run your AC on Dry Mode when you want drier air but do not want cooler air. That is, use your AC to dehumidify the air without changing the temperature in the room.  

Use Dry Mode for any of the following:

  1. Rainy days. The best time to use this mode is during clammy, rainy days when it is cool outside. 
  2. When you have shampooed your carpet and you’d like it to dry quickly. After your carpet is cleaned, it will still have some water trapped in the material. Left to itself, this water will slowly evaporate and cause your home’s humidity level to rise. Dry Mode eliminates that issue.
  3. If your house smells musty. When you notice your house smells moldy, it indicates that the carpet, upholstery and other materials have a high moisture content – there is too much humidity in your house. Run a dry cycle or two to remove excess moisture and get rid of musty odors. A
  4. If you see mold growth, then run Dry Mode in cool weather and AC Mode in warm weather until you can find and eliminate the cause of the mold growth. 
  5. When your energy bills are high. When needing to save a buck, it costs less to use Dry Mode than Cool Mode since Dry Mode requires less energy to run.  

What is the Best Temperature for Dry Mode?

Dry Mode is most effective for you when the weather outside isn’t warm enough to run the system in AC Mode. Most homeowners like to switch from Dry to AC when the air in their home rises to somewhere between 70°F (21°C) and 77°F (25°C). 

Contrary to popular belief, Dry Mode is also useful throughout the winter months. Different states get different types of air mass, and some regions experience humid winters. If you find yourself in a humid but cool season, follow the same rules you would for the summer season.

Tip: Keep Dry Mode on for no longer than two or three hours at a time. This allows enough dry cycle operation to remove excess humidity without making the air uncomfortably dry.   

How Long Should I Use the AC Dry Mode Setting?

Only until the humidity level is where you prefer it. You should keep the humidity level between 40% and 55%, and you must not have Dry Mode on for longer than three hours at a time. As some regions are less humid than others, you can gauge whether or not three hours is appropriate based on your area.

Keep in mind that a 55% humidity level cap is disputable. Some sources claim that the cap should be 50%. Regardless, it is imperative that you never allow the humidity level to exceed 55%, as the chances of mold growth and breathing issues increase.

To determine the exact humidity level in your home, use a hygrometer. You can find one in both analog or digital.  

Is it cheaper (save energy) to run an AC in dry mode? 

Yes it is. You save energy and money running dry mode. The data shows that running any type of air conditioning in Dry Cycle reduces energy use by 35% to 45%. 

Dry Mode will reduce your energy bill. This is due to the fact that the unit’s compressor and circulation fan work more slowly than during Cool Mode. When the unit is working less, you use less energy and, in turn, save more money.  

Air Conditioner Dry Mode vs Dehumidifier

The Dry Mode feature and a dehumidifier perform the same function. They both dry the air to make it less humid and clammy, and both reduce the risk of mold and mildew growth in your home. 

While a dehumidifier is an extra expense, using a dehumidifier can cost you less money month to month. This is because it requires less energy to operate than most AC types including a window air conditioner, portable air conditioner or mini split system. And given that it specializes in reducing moisture, compared to an AC unit that specializes in cooling air, a dehumidifier will perform a dry cycle better than an AC unit’s Dry Mode feature. 

There is one advantage of using Dry Mode over a dehumidifier, especially for central AC or ductless AC. It is that a dehumidifier dries air in one specific location while central and mini split air conditioning dry air in the entire home. 

You should also keep in mind that if you live in an extremely hot and humid environment, you might have to run both a dehumidifier and an AC unit. This is especially true in space below grade such as the lower level of a tri-level or in a basement. 

The AC unit will reduce some of the humidity in your home, but the hotter days will strain it and hinder its performance. Having a dehumidifier on as a supplement will help you save energy and money. And it might prolong the life of your central AC system. 

Does the air conditioner dehumidify?

Yes, an AC will reduce humidity while on Cool Mode and Dry or Dehumidifier Mode. In both cases, the internal coil gets very cold by removing heat around it. Moisture from the air passing through the unit condenses onto the cold coil and drains down into a pan. The pan has a drain, and the water enters it and leaves your home. That’s how the air becomes drier. 

As mentioned above, Dry Mode is best used at times when you do not need your AC unit to produce cold air. Cool Mode, on the other hand, is best for hot days, as this mode will lower the surrounding room temperature and dehumidify at the same time. 

What is the difference between cool and dry mode in ac?

 The difference between Cool and Dry Mode is that the AC Cool Mode removes both heat and humidity from the air. Dry Mode only removes humidity. It does not cool the air. 

Dry Mode is designed for humid but cool days. AC Mode is ideal for warm weather when you want both cooler and less humid air.

Benefits of AC Dry Mode

Aside from reducing the humidity, there are several benefits to using Dry Mode:

  • It decreases the chances of mold growth on furniture, clothing, curtains, etc. 
  • It eliminates musty odors. 
  • It can help you breathe better indoors if your breathing is compromised and made more difficult by high humidity.
  • It helps reduce allergy issues indoors.
  • It produces a better sleeping environment.
  • It saves you money on your energy bills.
  • It protects your electronic devices and appliances. (Excessive moisture can damage these.)

When the Air is Too Dry

As you enjoy using your AC’s dry function, note that it is just as bad for your health if your home is too dry (i.e., less than a 45% humidity level). This is why you will want to be prudent with how much or often you use the Dry Mode setting. 

When the air is too dry, you can experience dry eyes, chapped skin, and a bloody nose, among other, less severe issues. On the severe end, you may find yourself frequently sick with respiratory illnesses and nasal congestion, which, over time, can cause lasting side-effects.

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.
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