The air conditioner and dehumidifier are often a subject of debate when talking about indoor cooling and air quality solutions. Air conditioners work to reduce the temperature in a room, making you feel cooler and more comfortable. Meanwhile, dehumidifiers extract moisture from the air to help maintain relative humidity levels between the ideal range of 30% to 50% RH.
As summer rolls around, many homeowners are concerned with the heat and excess humidity that come along with it. However, both these appliances are not only useful during hot and humid summer days. Depending on the region you live in, humidity can be a problem any time of year. You may need a dehumidifier more than an air conditioner, or vice versa.
If you want to learn which one you need, let us find out what they do and how they work. Then, you can choose the one that best fits your needs.
Dehumidifier vs Air Conditioner—What is the Difference?
Both an air conditioner and a dehumidifier affect the air temperature and relative humidity in an indoor space. There are also a lot of similarities in the function and parts of an air conditioner and a specific type of dehumidifier. Due to the relationship between temperature and humidity, they can also have similar effects to a certain level. However, the main difference is their purposes.
The main purpose of an air conditioner is to remove warm and wet air and introduce cool air into a room, which can also reduce humidity levels as a consequence. On the other hand, the main function of a dehumidifier is to pull excess moisture from the air. So, depending on your more pressing concern—temperature or humidity—you may need one over the other.
Air conditioners have a thermostat built into them so they can adjust the temperature automatically according to the selected settings. A lot of dehumidifiers have a similar feature: a built-in humidistat that automatically controls relative humidity.
Dehumidifiers are typically more compact and portable, with wheels and handles for convenience. Although non-central air conditioners are commonly installed in a window or through the wall, some models also come in a quiet and portable design for short term temporary applications. Portable air conditioners typically use an exhaust hose that connects to a window to release the warm air generated from the refrigerant to the outside of the room.
How an Air Conditioner Works
An air conditioner works in the same principle as a refrigerator, in that it transfers heat from inside the room to the outside, reducing the temperature. The main components of an air conditioner are the evaporator and condenser coils, the compressor, and fans that circulate the air inside the system or blow the air out.
The cooling process starts as warm air enters the cooling system through a fan. This air passes through a filter where dust, lint, and other airborne particles are collected. The air then passes through the cold coils, which cools the air. While hot air blows over the liquid refrigerant inside the evaporator, it decompresses and converts to a warm gas, absorbing the heat from the air.
The cool air is pumped back into the room and the warm air is pumped outside. Meanwhile, the refrigerant gas flows through the warm coils where it converts back into liquid form, releasing the heat.
How a Dehumidifier Works
Dehumidifiers work to reduce the amount of moisture in the air. They accomplish this task through different processes.
What most people are familiar with is the compressor or refrigerant dehumidifier. It works similarly to an air conditioner as it uses a compressor to move the coolant from the condenser to evaporator coils to remove moisture from the air.
A fan draws the humid air into the machine and passes it over the cool coils. As the temperature decreases, the air loses its ability to hold water vapor. Moisture condenses and the water formed drips down into the internal tank or out through the drain hose.
The dryer air is then reheated and exhausted into the room at a temperature about 2°C or 4°F higher. Due to this process, this dehumidifier generally performs well in warm climates. It can only operate in temperatures as low as 41°F, while its efficiency starts to decrease at 65°F. Standard refrigerant dehumidifiers today have the capacity to remove 20 pints to 50 pints of moisture per day.
A typical whole-house dehumidifier works with the same process including a bucket or tray mechanism or a built-in condensate pump to automatically drain excess moisture. For homes in humid conditions, it may be more efficient to use whole-house dehumidifiers instead of buying a portable unit for each room.
Another method that portable dehumidifiers use is called the Peltier effect or thermoelectric cooling. It works almost similar to a refrigerant dehumidifier but on a smaller scale. Instead of a compressor, evaporator, and condenser, this dehumidifier consists of a Peltier module and a hot and cold heat sink on either side of the Peltier element.
Humid air is drawn by a small fan through the cold side, where the moisture condenses into water, which collects in a tank. The now cold and dry air passes through the other side which warms the air and releases it back into the room.
Since a Peltier dehumidifier also needs to cool down the air first to pull moisture, it operates optimally in warm temperatures between 59°F and 89°F. It can remove 8 oz up to 30 oz of moisture per day, a much lower capacity than a refrigerant unit.
The other type of dehumidifier is called a desiccant. It uses a hygroscopic substance (usually calcium chloride or silica gel) that extracts moisture from the air until it is fully saturated. Desiccant dehumidifiers come in a variety of sizes, depending on the capacity and renewability of the desiccant used.
There are disposable units that come in small containers, and renewable ones that need to be recharged every few weeks. Full-size desiccant dehumidifiers feature a desiccant wheel filled with silica gel. The humid air passes through a portion of the desiccant rotor, where moisture is adsorbed. Dry air is pushed out through a fan. This part of the rotor is heated so that moisture is desorbed and forms water droplets. The desiccant is now reactivated and ready to extract moisture again.
Since desiccant dehumidifiers don’t need to cool down the air to remove moisture, they continue to operate even in low temperatures. However, they are usually more expensive and have a lower capacity.
When to Opt for Air Conditioners and Dehumidifiers
To reiterate, dehumidifiers and air conditioners perform different functions in your HVAC system but yield a few similar results. In particular, air conditioners remove heat from the room while dehumidifiers pull moisture from the air.
For a better understanding of these functions, let’s look at the relationship between temperature and humidity. Relative humidity refers to the amount of water in the air compared to the maximum amount it could hold at a given temperature. Although it has zero effect on temperature, humidity can change our perception of temperature.
Likewise, the temperature does not directly impact humidity. However, hot air can hold more water molecules. Thus, given the same amount of moisture in the air, the relative humidity decreases as temperature rises.
Keeping this in mind, let’s answer a few questions:
Sweat helps your body stay cool, but when there is high relative humidity, the air is already saturated with moisture and cannot absorb your sweat. So when humidity levels are high, the hot temperature feels even hotter and the air feels heavy and sticky. As the dehumidifier removes moisture from the air, it reduces the humidity level. Because of this change in relative humidity inside the room, the air can feel cooler to you.
To answer the question, dehumidifiers do not actually make a room cooler. In fact, the air temperature upon release is a few degrees higher than the intake. On the other hand, cold air is able to hold less water vapor. This is why cold winter air often lacks moisture, and thus, there’s less need for a dehumidifier.
Can an AC Handle Moisture Like a Dehumidifier?
An air conditioner removes heat from the room and lowers the temperature. In consequence, it helps reduce the humidity. However, cooling down heavily moist air makes the job a lot tougher for your air conditioner, which can lead to higher cooling costs. Meanwhile, the air conditioner is not equipped to remove excess moisture to the level that a dehumidifier does. During hot and humid summer months, your air conditioning unit alone may not be enough to remove all the moisture and maintain optimal temperature and humidity.
Is It Cheaper to Run an AC or a Dehumidifier?
Upon purchase, air conditioners are usually more expensive than dehumidifiers, but the actual energy consumption can vary greatly depending on the brand, type, and size. Dehumidifiers have a few similar components and working principles, but their refrigerant systems don’t have to work quite as hard as those of AC units to decrease the air temperature. As a result, dehumidifiers generally consume less electricity than the equivalent AC. Therefore, running a dehumidifier alone will cost less than running an air conditioner.
However, if you’re choosing a dehumidifier over an AC just to save on your electricity bills, keep in mind that a dehumidifier is not designed to cool a room. Likewise, an AC unit cannot function to the same level as a dehumidifier and you may end up spending even more on electricity.
Best Dehumidifiers for Homes in 2023
Dehumidifiers help maintain healthy levels of relative humidity inside your home. This makes the environment inhospitable for mold, mildew, dust mites, and other airborne allergens. Consequently, this reduces the risks of respiratory issues and other health problems and also prevents damaging effects on properties. Additionally, dehumidifiers work to eliminate unpleasant odors and improve poor indoor air quality. Unlike a portable dehumidifier for single rooms, a whole-house dehumidifier can do all of these for the entire house.
Below are some of the best-selling dehumidifiers you can use in your home depending on your specific needs:
Frigidaire FFAP5033W1 50-pint Dehumidifier with Pump
hOmeLabs HME020031N 50-pint Dehumidifier
Pro Breeze Mini Peltier Dehumidifier
Eva-Dry E-500 Renewable Mini Dehumidifier
Best Air Conditioners for Homes
Air conditioning units are a lifesaver during hot summer days. There are different types of ACs depending on the installation requirements.
Window-type is the simplest to install; you just need a window that fits the required dimensions. Wall air conditioners are almost similar except they are fitted into a wall with a sleeve. Portable units generally have a smaller cooling capacity and are less efficient but they come with wheels for easy transport. Split systems are designed for higher energy efficiency and quiet operation, but are more expensive and difficult to install. Lastly, central air conditioners distribute cooled air to multiple rooms in your home, but it can be less efficient and more expensive.
We list below our top picks for a quiet, efficient, and affordable air conditioner in your home:
Midea U Inverter Window Air Conditioner
LG LW1019IVSM Dual Inverter Window Air Conditioner
Koldfront WTC8001W Wall Air Conditioner with Heater
Whynter ARC-14S Dual Hose Portable Air Conditioner
To sum it up, your need for a dehumidifier vs an air conditioner mainly depends on the climate. If you live in a hot environment, you may go for an air conditioner, which can cool the room and also reduce humidity. If you live in a region of temperate climate with high humidity, then a dehumidifier may be more useful. However, if you have issues with both temperature and humidity, then you can benefit most from these two appliances working together. In any case, make sure you’re using the appliance for the purpose intended for it.