Is It Cheaper to Run the AC or a Dehumidifier?


Air Conditioners and Dehumidifiers help maintain a comfortable and safe living environment at home.

But this comfort comes at a price and many homeowners wonder whether it’s cheaper to run an AC or a dehumidifier? Generally, it is cheaper to run a dehumidifier than an AC if both units are of average capacity and have typical running times. Regardless, this does not mean that you should get rid of your AC and replace it with a dehumidifier since each has its own function.

Both ACs and dehumidifiers have their uses, and understanding them will prevent you from needlessly picking one over the other.

As a general rule, you can expect to pay this much on your monthly electricity bill:

  • Portable dehumidifiers cost $25 to $350 per year overall, depending on their capacity. This breaks down to $2 to $29 per month, although this isn’t exactly a correct way of looking at it. Most dehumidifiers, just like AC units, run non-stop in the hot and humid winter months, while they barely run or even are stashed away for the winter season.
  • Central air conditioners typically add $80 to $125 each to your monthly electricity bill.
  • Mini-split air conditioners with an average capacity (about 12,000 to 20,000 BTU) cost about $35 to $50 per month in electricity. You can expect approximately half that cost for portable or window AC units with similar BTU capacities.

Now that you know the costs, let’s figure out the similarities and differences between your AC and dehumidifier.


Air Conditioning vs Dehumidifiers

Air conditioners and dehumidifiers deal with air-related issues, but selecting just one of them is not what you should be looking at. While the two units might seem similar to most, they actually tackle distinct problems. To better understand what these two devices do and how they are different, let’s look at how each of them work.


Air Conditioners: What It Does and How It Works

In short, air conditioners replace warm air with cooler air. It is also a major part of your HVAC system. Most air conditioners comprise 5 basic parts. They are the evaporator coils, condenser, compressor, expansion valve, and a set of fans. In addition to these parts, ACs also have a cooling fluid called the refrigerant pumped along inbuilt pipes.

The refrigerant is initially a liquid, but once it passes through the expansion valve, it turns into a cold gas which is then passed towards the evaporator coils. As the cool refrigerant passes along the evaporator coils, it absorbs the surrounding heat which cools the nearby air. The cooled air is then blown into your room by a set of fans.

The process does not stop here, the once cool refrigerant gas is now hot. Therefore, to remove the heat, the gas is compressed using a compressor and pumped through condenser coils. Another set of fans blow over these condenser coils, cooling the gas and blowing away heated air. This set of fans is installed to direct hot air outdoors. By now the refrigerant is back to its liquid state and ready to repeat the process.

It is clear that the primary function of an AC is to transfer heat from the air indoors to the air outdoors. But this process also lowers the humidity levels at home. So, how can a device built for heat transfer affect the moisture content in the air?

The culprit behind this is condensation. Humidity holds heat, so when the heat is removed at the evaporator coils, it condenses the moisture in the air as well. The condensate pan below the evaporator coil then collects the liquidized water vapor. This is the reason some people use air conditioners as dehumidifiers.

But dehumidification is just a subprocess of an air conditioner, so it might not deliver the results you are looking for unless it comes with a mode that allows you to control the dehumidifying process.


Dehumidifier: What It Does and How It Works

Dehumidifiers, unlike air conditioners, are designed to deal with high levels of humidity. It removes the excess moisture from the air, making your home more comfortable and safe. The working principle of a dehumidifier depends on its type. There are three common types of dehumidifiers, each with a unique method of operation.


Desiccant Dehumidifiers

A hygroscopic (meaning, water-absorbing) substance commonly called a desiccant is used in these dehumidifiers. Desiccants have the ability to absorb moisture from their vicinity. Because the dehumidification process of these dehumidifiers is relatively simple, it does not consume large amounts of energy.


Thermoelectric Dehumidifiers

These humidifiers are also called Peltier dehumidifiers. It contains a material that creates a hot and cold region, once electricity is supplied to it. The cold region is responsible for removing moisture from the air.


Refrigerated Coil Dehumidifiers

This is what most people use in their homes.

The working principle of a refrigerated coil Dehumidifier is similar to that of an air conditioner. It uses a coil that is cooled to draw in the hot and moisture heavy air. Once the heat is removed along with the water vapor, the humidity level drops.


Energy Consumption

Energy consumption is a key detail that can not be ignored when the running cost of an electrical device is of concern. On average, the energy consumption of a dehumidifier is less than that of an air conditioner. If both the appliances were to run for 24 hours, the AC most often than not would consume more power.

But in day-to-day life, this is not always true because the energy consumption of these devices largely depends on their capacities and running times. The capacity of an AC is measured in tons. The tonnage of an air conditioner refers to the rate at which heat can be removed from a room. Models with larger capacities consume more power. Similarly, dehumidifiers with large capacities also tend to consume more energy. However, the capacity of a dehumidifier measures the amount (usually pints) of water it can remove in a day, unlike air conditioners.

The running times also factor into the total energy consumption of a device. A dehumidifier with a large enough capacity can lead to more energy consumption than an AC if run for longer periods of time. Given these points, it’s wise to keep in mind that the amount of power consumed always depends on the work done, regardless of it being an AC or a dehumidifier.


Making The Right Choice

Now that you have a solid idea about what an AC and a dehumidifier does and the energy consumption of these devices, let’s pick the correct machine for your needs. To do this, we need to look into the pros and cons of both these devices first. Knowing them will help you make the right choice.


Pros and Cons of an Air conditioner

The air conditioner is best for controlling the temperature in a room, even though it naturally acts as a dehumidifier as well. It also contributes a lot to the air circulation in a room. If you use an AC solely to control the humidity levels, it will also cause a significant drop in the temperature. Therefore it is not ideal to use an air conditioner as a dehumidifier if you need to keep the surrounding temperature constant.

All things considered, an air conditioner is the best choice to cool the air and improve the airflow as well.


Pros and Cons of a Dehumidifier

Dehumidifiers, on the other hand, are perfect to remove excess moisture from the atmosphere. It will do so while keeping the temperature constant. If mold, mildew, or wood rot is a problem, a dehumidifier will do a good job at controlling them. Additionally, it will also improve air quality by removing pollutants such as mold spores from the air.

So, if you looking to control the humidity levels along with improving the overall air quality, a dehumidifier is what you need.


Run Them Together

Another option worth considering is running both these devices together. It may seem counter-intuitive, but this method can actually reduce costs and also create a comfortable living space without having to choose one device over the other.

An air conditioner typically uses more energy than a dehumidifier. But if a dehumidifier is used alongside an AC, the burden on an air conditioner will decrease. This is because when a dehumidifier removes excess moisture, it also cools the surrounding air to a certain extent, which will cause the AC to do less work than usual. As a result, the air conditioner will consume less power, significantly cutting down its running costs.

To pull this off, first set the AC to a fixed value. While the AC is off, use the dehumidifier to cool and maintain the surrounding air. Once the temperature rises above the fixed value, the AC will turn on and help to bring it back down.


Related Questions

How do you control the humidity with just an air conditioner?

Naturally, the air conditioner will remove moisture from the air as it cools the surrounding. If you need more control over the humidity levels, you can adjust the fan speed to your liking. Increasing the speed of the AC fan will remove more moisture from the air, but will also lead to more power consumption.


What does the dry mode of an air conditioner do?

The dry mode is a function built-in to most modern air conditioners that reduces humidity levels. This feature can be used when you need the air conditioner to act as a dehumidifier without its cooling capabilities. The air conditioner will operate as usual but won’t blow out cold air when functioning on dry mode.


Is the air conditioner-dehumidifier combo really effective?

The combo is very effective if you want to experience the benefits both devices offer. It will cut down costs significantly, unlike running an AC throughout the day.