Short answer: Desiccant dehumidifiers produce minimal heat compare to the more common dehumidifier types (like Refrigerant Dehumidifiers, or even Peltier Dehumidifiers). Keeping reading to learn why, as well as why certain types of desiccant dehumidifiers can still generate heat.
Longer answer: A dehumidifier typically makes the room *feel* cooler, even if it technically increases the ambient temperature by a few degrees. Keep reading to learn why.
A dehumidifier works to reduce the amount of moisture in the air. The most common type of dehumidifier (refrigerant type) pulls humid air from the room, cools the air, then heats it and exhausts dryer air. Like any other electrical appliance, a refrigerant dehumidifier will always produce a small amount of heat when running. It can increase the ambient temperature by a few degrees, however, it can sometimes make the room feel cooler because of the changes in relative humidity.
High relative humidity can make the air difficult to breathe. Too much moisture in the air can feel uncomfortable and cause allergic reactions due to airborne allergens that thrive in humid environments. If left unattended for long, high humidity may lead to irreparable damage to properties in the form of fungi and pest infestation, rust, and corrosion.
To prevent humidity issues, homeowners invest in dehumidifiers to remove excess moisture and keep humidity levels within the optimal range of 30% to 50% RH. If you’re concerned about the heat produced, it’s perfectly normal for any device running on electricity. However, there can be instances where hot air from your dehumidifier signals a problem with the unit’s components. Keep reading to learn more
What Does a Dehumidifier Do?
The primary function of dehumidifiers is to lower the humidity level in an indoor space. They accomplish this task using different methods. Towards the end of the dehumidification process, a dehumidifier typically heats the air before it’s released back into the room. Because of this, the air surrounding the device feels warmer.
Although, in general, lower humidity can help make the room feel cooler to its occupants. This is because perspiration evaporates well into less saturated air. There are also some secondary benefits to using a dehumidifier. Lower humidity is inhospitable for harmful organisms such as mold, mildew, dust mites, and other allergens. Additionally, dehumidifiers eliminate unpleasant odors and helps improve overall air quality. Lastly, it can help dry laundry faster, preserve food in storage, and protect electronic equipment and other important items.
Types of Dehumidifiers
The two main types of dehumidifiers are based on the process in which they collect moisture from the air: condensation and absorption or adsorption. Depending on the ambient humidity and temperature as well as the size of the room, each type has its own advantages and disadvantages.
A refrigerant or compressor dehumidifier works similarly to an air conditioner. It pulls in warm, humid air and condenses the moisture to water.
On the other hand, a desiccant dehumidifier uses a chemical that absorbs or adsorbs moisture from the air until its maximum capacity is reached then the desiccant is heated up.
Another method of dehumidification that mini dehumidifiers often use is called the Peltier effect or thermoelectric cooling, which also uses condensation.
Why Dehumidifiers Produce Heat
A compressor dehumidifier uses condensation to extract moisture from the air. It uses a compressor to heat up the refrigerant that circulates through the condenser coils. Moist air enters the device through a fan then passes through the coils. As the temperature drops, the air loses its ability to hold water vapor. Moisture then condenses and the water formed is then collected in a tank or pushed out through a drain hose. After moisture is removed, the air is then reheated and exhausted back into the room. You may notice warm air coming from the unit if you’re standing close to it.
Since this type of dehumidifier has to cool the air considerably, its performance declines in cold temperatures. They are hugely effective in warm and humid weather since cold air has less humidity. Most consumer-grade refrigerant dehumidifiers can only operate in temperatures as low as 41°F and their efficiency starts to decrease from 60°F.
Disposable and Renewable Desiccant Dehumidifiers
There are different types of desiccant dehumidifiers depending on the moisture extraction capacity, coverage, and renewability. The smallest and cheapest ones are the disposable desiccant dehumidifiers or moisture absorbers in tubs or containers, which are small beads that absorb excess moisture. They have a very low dehumidifying capacity and do not need electrical power.
Similar to the disposable desiccant in terms of size and capacity are the renewable desiccant dehumidifiers. The difference is they contain renewable silica gel which removes moisture from the air through adsorption. They also do not need to be plugged to work, but you need to recharge them every few weeks to dry out the moisture collected.
Since these dehumidifiers do not actively use electricity when dehumidifying, they do not usually produce heat. However, they are typically only used in tiny spaces such as cabinets, safes, and storage areas.
Full size and rotary desiccant dehumidifiers
Lastly, full-size desiccant dehumidifiers are about the same in appearance as refrigerant models but lighter and quieter since the former don’t use compressors. Inside is a desiccant wheel that constantly rotates to process the air.
Moisture clings to the surface of the desiccant material, separating it from the air molecules. A heater warms the circulated air before it passes through the saturated desiccant. Moisture is then desorbed or transferred from the desiccant to the warm air, renewing the desiccant so it can adsorb moisture again. The cycle repeats and moisture is collected in a tank. Since it has a heater and always warms the air, it will produce some amount of heat when running.
The Peltier technology is based on the idea that a voltage of electricity creates a temperature difference between the two sides of a Peltier module. A Peltier or thermoelectric dehumidifier works by drawing in moist air through a small fan on the colder side. As the air cools, the moisture condenses and drips down to the water tank. The cold, dry air then passes through the hot side, and warmer, dryer air is released.
The process is not that different from that of a refrigerant dehumidifier, but instead of using a compressor to cool the air, a Peltier dehumidifier converts the current into a temperature gradient. As is the case with compressor models, the efficiency also decreases in cooler temperatures. The optimal condition is from 56°F to 90°F and the daily capacity is about 10 to 50 times smaller than a regular compressor dehumidifier.
How to Minimize the Amount of Heat Generated by Dehumidifier
While it’s normal for electric dehumidifiers to generate some heat when operating, there may be cases when the heat is not in proportion with the size of the unit or the room. By observing proper usage and maintenance, you can prevent your dehumidifier from heating up too much.
First, always use the right dehumidifier size. Getting the right capacity for your space maximizes the effectiveness and energy efficiency of your dehumidifier. If you use an undersized dehumidifier, it has to work really hard to keep up with the task, causing it to produce too much heat. Likewise, an oversized dehumidifier will add more heat to the room. Also look for an energy efficient dehumidifier with high Energy Star rating.
Once you have the correct size, find the best location to place your dehumidifier. Look for the main source of humidity in the area and keep all doors and windows closed while the dehumidifier runs so that it works only in one specific area. Make sure that the air isn’t blocked from the intake and exhaust grilles. Place the unit at least a few inches away from walls or furniture to maintain airflow.
Keep the dehumidifier clean. Dehumidifiers typically require very little maintenance, but you must still check up on your unit from time to time to ensure your health and comfort and help your dehumidifier last long. Use a damp cloth to wipe the exterior and vacuum the inside to remove dust or dirt. Take out the air filter and wash it with liquid soap. Let everything dry completely before reinstalling.
Operate in tandem with your air conditioner. During hot and humid days, your air conditioning unit alone may not be enough to keep the indoor environment comfortable. Air conditioners work to lower the temperature, and in turn, helps reduce the humidity. However, cooling down heavily moist, hot air makes the job a lot tougher for your air conditioner, and this is where your dehumidifier comes in. Together they can cool the air and reduce the humidity for your utmost comfort.
These are only some basic rules you can follow to reduce dehumidifier heat and keep your unit functioning properly. In case you notice your unit produces more heat than usual, check its internal components and perform routine maintenance. If you can’t find the problem, have the unit checked by a professional.
Other Ways to Control Indoor Relative Humidity
Dehumidifiers naturally create heat when operating. If you want to reduce your use of a dehumidifier, here are some ways that can help reduce indoor humidity without a machine.
The easiest way is to improve ventilation by opening your windows and doors. Run your fans to let the air circulate. When you cook or take a shower, turn on your exhaust fans or simply crack a window open. This helps keep the excess moisture and odors out.
Avoid hanging wet clothes indoors. The best solution is to hang your laundry outside, but if this isn’t possible, you can also use a dryer or fan.
You also try some alternative options for a dehumidifier. Just put calcium chloride in a bucket or a large bowl and place it where it’s humid. You can even use moisture absorbers you’ll find in your pantry such as rock salt and baking soda.
If you’ve done all these measures and you still have excess humidity, check your plumbing. Fix any leaking pipes under sinks, in the bathroom, or in the basement.
Each of these methods can help lower humidity levels or remove the source altogether. Some may take more effort, time, and money, but if you have serious humidity problems, these may not be enough to fully address them.
A dehumidifier is a good investment for any home suffering in high humidity levels. It can help reduce moisture and eliminate mold, dust mites, and other airborne allergens that grow rapidly in moist environments. While a dehumidifier is usually easy to use and maintain, one problem you may face is its tendency to produce extra heat in the room. This is normal for any dehumidifier that runs on electricity because it has to suck in damp, cool air, cool it down further, then heat it up again. In short, there is no dehumidifier that does not produce heat. However, if ever it becomes an issue to you, there are ways to maintain your comfort and still benefit from your dehumidifier. With proper use and maintenance, you can easily reduce the heat you get from the dehumidifier. If the exhaust air gets too hot, check if all components are functioning as needed or have the unit examined by a professional.