Dry Mode In AC Explained: What Does Dry Mode Do? Electricity Usage?

If you have high humidity, the Dry Mode in air conditioners is the go-to mode. A lot of people have been asking us what does Dry Mode in AC mean. Now would be a good time to explain this dry mode (or dehumidification mode in AC) in detail. We are going to cover these 3 key topics:

  1. What does Dry Mode on AC do, and when should you run your AC in Dry Mode?
  2. How does the Dry Mode in AC actually work?
  3. Does Dry Mode use less electricity? Obviously. But how much less electricity will an AC use in ‘Dry Mode’ vs ‘Cooling Mode’?
dry setting on mini split ac or heat pump (1)
The cold indoor evaporator coil is the key to dry mode on AC units (mini splits) or heat pumps.

Now, let’s first point out that an air conditioner is quite a versatile appliance. It can cool, reduce humidity (dry), generate only airflow, and so on. Here are the 6 standard air conditioner modes:

  • Cool mode. This will cool as well as reduce humidity.
  • Dry mode. We will look into this one further on, but the most basic purpose is that Dry Mode reduces humidity (without cooling).
  • Fan mode. Only creates airflow (no cooling, no drying).
  • Turbo mode. Usually cooling mode that runs on 100% BTU output.
  • Sleep mode. Low airflow cooling mode that runs as quietly as possible (reduces dB output).
  • Eco mode. The most efficient way to run an AC unit in cooling mode (usually around 30% to 60% BTU output, never at 100% BTU output).

Alright, now that we know what pretty much every air conditioner can do, let’s look at what the Dry Mode actually does:

What Does Dry Mode On AC Do? When Should You Use It?

In most basic terms, picking ‘Dry Mode’ on AC remote control will turn the air conditioner into a dehumidifier. What does the dry setting on an air conditioner do? It does only this 1 job:

  • Reduce indoor relative humidity levels.

That’s it. If you have a humid home (humidity levels between 50% and 100%) and would like to reduce it to the recommended 30% to 50% relative humidity levels, you should run the air conditioner in Dry Mode.

Here it is important to note that an air conditioner in Dry Mode will dry the air, but it will not cool it (no significant reduction in indoor temperature). That means that the perfect situation in which we use Dry Mode is when we have both:

  1. High humidity levels. That’s 50% to 100% RH; the air in your home feels moist, and you have an extra danger of mold growth (high humidity = risk of mold growth).
  2. Normal temperature. When the indoor temperature is over 80°F, you will obviously want to cool your home; that’s what the ‘Cool mode’ is for. When the temperature is between 70°F and 80°F, for example, and you feel that the temperature is OK, but the home feels humid, you would switch to Dry Mode.

There are 3 key advantages of using the dry setting on an AC unit or a heat pump:

  1. Nothing lowers the humidity levels quite like Dry Mode. The AC unit turned into a 100% dehumidification machine.
  2. You are able to lower the moisture levels, without that chilling cooling effect. Running an AC unit to remove air moisture (on standard cool mode) can have an unwanted effect of producing too low indoor temperature. Dry levels just removes the moisture, without chilling the place out.
  3. Lower electricity usage. Because the AC unit doesn’t kick-in the energy-consuming cooling output, you will save electricity on Dry Mode. We will discuss more about how much power does an AC on Dry Mode use later on.

Let’s look at exactly how does the Dry Mode on AC work:

How Does Dry Mode On AC Work?

All air conditioners remove air moisture via condensation. That’s the same effect you see when the water droplets form on a glass of perfectly chilled beer. To capture the air moisture via condensation, you need two things (both of which AC on Dry Mode has):

  1. Very cold material. In the case of air conditioners, these are the indoor evaporator coils. Using the refrigeration cycle, the AC unit uses refrigerant (R134A, R22, R32, R410A, etc.) to cool indoor coils. In our beer example, this is the cold glass.
    cold evaporator coils condensing water when on dry mode
    These are indoor cool evaporator coils that condense the water from humid air.
  2. Humid airflow over the cold material. AC in Dry Mode uses the fan to produce a low CFM airflow over the cool evaporator coils. When the air comes into contact with these freezing coils, it will form droplets on the coils (that’s captured air moisture).

These water droplets will drip into the dripping pan and be channeled outdoors via the condensation hose. Here is what is happening with the air:

  • Moist air enters the AC unit on dry setting.
  • Dry air exits the AC unit on dry setting. The output air can be a bit colder, but this effect is not significant; not nearly as significant as in a cool setting.
ac on dry setting vs dehumidifier difference
The main difference between AC on dry mode and a dehumidifier is that a dehumidifier has hot coils. This hot coil heats the slightly cooled air back to room temperature before returning it into our home.

The AC only has to spin the fan slowly and provide refrigerant for cooling the indoor coils. That means that we will see a reduction in power consumption when AC is on Dry Mode. How much electricity do we save? Let’s try to estimate this:

How Much Less Electricity Does AC Use On Dry Mode?

We made an analysis of how much electricity air conditioners use here. Here are 2 examples that neatly summarize the benchmark AC electricity usage:

  1. A 3-ton 16 SEER unit will, on average, run on 2,250 watts. That will use 2.25 kWh per running hour. At $0.15/kWh electricity rates, that’s $0.34 per hour.
  2. A 12,000 BTU portable AC unit with a 10 EER rating will have max. wattage of 1,200 watts. On average, however, it will run on 684 watts. That’s 0.684 kWh per running hour, or $0.10 per hour.

AC in Dry Mode still needs to run the power-hungry compressor (to get cool refrigerant), but it will run at about 25% to 50% of the capacity compared to the cooling mode. Similarly, the indoor fan will also spin much slower and won’t need that many watts for that.

As a result, we can estimate that an AC on Dry Mode uses about 25% to 50% of electricity, compared to the cooling mode. That presents a 50% to 75% reduction in electricity usage.

If we look at our 2 examples above, here are the estimated Dry Mode electricity usage and AC running cost:

  1. A 3-ton 16 SEER unit on Dry Mode will use anywhere from 0.56 kWh to 1.12 kWh per hour. At $0.15/kWh electricity rates, that’s anywhere from $0.08 to $0.17 per running hour.
  2. A 12,000 BTU portable AC unit with a 10 EER rating on Dry Mode will use anywhere from 0.17 kWh to 0.34 kWh per hour. At $0.15/kWh electricity rates, that’s anywhere from 2.5 US cents to 5 US cents per running hour.

We hope that this explains well what does Dry Mode on AC do, how this mode works, and how much electricity you are likely to save if you run an AC or a heat pump on Dry Mode. If anything is unclear, you can use the comment section below and ask us anything, and we’ll try our best to explain it. Thank you.

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