Dehumidifiers play an important role in managing humidity. They can protect your home and belongings but also play a vital role in many industrial processes. However, you have to use the right type of dehumidifier, or it isn’t going to be effective.
There are many different types of dehumidifiers, and it’s not always easy to know the differences. Don’t worry; in this guide, I’ll show you all the different types of residential and industrial dehumidifiers to choose from and help you determine which is best for you.
Different Types of Residential Dehumidifiers
Residential dehumidifiers are used to regulate humidity levels within your home. They come in a wide range of shapes and sizes, and the model you choose should match the particular humidity issue you’re dealing with.
Here are the main types of dehumidifier you should consider for home use:
1. Refrigerant/Compressor
Refrigerant models are the most common residential units. These work using a cold evaporator coil filled with refrigerant and an electrical fan. The fan draws in moist air, and it’s pulled over the cold coil. This causes the air to cool and form condensation. It’s then gathered within the device, and the air is then warmed and released back into the room.
There are fixed or portable dehumidifiers to choose from, and there are usually options suitable for most jobs. The real advantage of these dehumidifiers is that they work quickly to reduce humidity. The downside is that the refrigerant within the condenser coil can freeze at temperatures under 60 degrees Fahrenheit.
If you’re using this indoors in a warm enough environment, it’s a great choice, but if you live in colder climates, there may be better options.
2. Desiccant/Absorption
Desiccant dehumidifiers use a simpler method to remove moisture. Instead of cooling coils, they use an absorbent material (typically silica gel or zeolite) which naturally absorbs water vapor from the air.
Desiccant dehumidifiers often use a fan system for drawing air into the device, but they can just sit in a small space to passively lower humidity. As air passes over the absorbent desiccant material, it will take moisture out of the air. Eventually, the absorbent material will be saturated with water, and either needs to be dried or replaced.
Desiccant dehumidifiers work well in cold climates as there are no coils to freeze. Many models also don’t use any electrical energy, so they make a useful portable dehumidifier for spaces without power.
However, desiccant dehumidifiers are less efficient and quick at lowering humidity levels, so they are best used in smaller rooms with limited moisture.
3. Whole-Home
Whole home dehumidifiers operate using a large, central dehumidifier connected throughout your home using a series of ducts. They are often part of whole-home HVAC systems that offer heating, cooling, air conditioning, and dehumidification.
Whole home dehumidifiers typically use refrigerant coils and draw in air from several rooms at once. The moisture is removed, and dry air is blown back into your home. The condensed moisture is then safely drained outside.
A whole-house dehumidifier is most useful in homes with high humidity that need year-round dehumidification. They can be expensive to install, especially if you have no existing ductwork, but if you have a large humidity problem that isn’t isolated in one area of your home, then it’s worth it.
4. Homemade/DIY
If you aren’t dealing with too much moisture and don’t want to spend much money on a dehumidifier, you can create your own. These typically work using the same principle as a desiccant dehumidifier and use materials with high dehydration capacities. [1]
Placing charcoal, salt, or baking soda in a bowl will provide natural dehumidification in your home. Eventually, the condensed water will be absorbed by the material, and you’ll need to replace it.
The big advantage of homemade dehumidifiers is that they are very cheap to make and work in high or low temperatures. The downside is that they have no fan to direct air and will take much longer to reduce humidity.
Different Types of Industrial and Commercial Dehumidifiers
Commercial and industrial dehumidifiers are designed to deal with a lot more moisture. They are often operating in conditions with poor insulation, like storage warehouses and building sites, and they will be dealing with a much higher humidity level.
Most dehumidifiers for home use are fairly similar, but there are many more types of an industrial dehumidifier to choose from:
1. Condensate
Condensate dehumidifiers operate using a cold surface to collect water. The cold surface is usually potable water, and as warm air comes into contact with it, the water vapor will be released as condensation. This is then gathered into a storage tank, and the dry air is released back into the room.
Condensate dehumidifiers often have reverse osmosis filters to change the gathered water into potable water so it can be reused within the device. In some models, water evaporates to be safely drained in a different location. Either way, there is very little waste with the moisture discharging safely away from the location.
These industrial dehumidifiers are generally used in large spaces where the relative humidity is high. They’re not portable and expensive to set up, but they will deal with high volumes of moist air.
2. Electric Refrigeration
Electric refrigeration dehumidifiers work in a similar way to residential refrigerant dehumidifiers. Moist air is pushed over a refrigerated evaporator (cold evaporator coils) using a fan. The refrigeration device condenses the water from the air and drains it away from the device. The dry air is then heated back up and released into the room.
Electric refrigeration works best in higher ambient temperatures with a higher dew point [2]. They will be less effective in the cold and won’t work at all in subzero conditions, so they may not work as well in very exposed buildings.
3. Spray
Spray dehumidifiers work using chilled water which is brought to a temperature below the room air. This water is then mixed with the humid air, and the low temperature forces the air to condense more quickly so that water can be removed from the surrounding air.
Spray dehumidifiers require a lot of energy to cool the water but are very effective even in lower temperatures. They also help capture pollutants while lowering the humidity level and actually make environments healthier, often called air washers.
4. Ionic Membrane
Ionic membrane dehumidification methods operate at a molecular level. They use a solid polymer electrolyte membrane with a very small amount of voltage passing through it.
This porous electrode attached to the membrane separates water into hydrogen ions and oxygen ions. The hydrogen within the incoming air is able to pass through the membrane, leaving the water molecules discharging on the other side.
The advantage of ionic membrane dehumidification and SPE systems generally is that they take very little power and almost no maintenance. The downside is that these types of dehumidifiers can’t handle high amounts of moisture. An ionic membrane dehumidifier is less useful in large floor space areas or damp areas like pool rooms.
5. Chemical Absorbent
A chemical dehumidifier is essentially a desiccant dehumidifier. They use hydrophilic materials which absorb moisture from the air and leave you with drier conditions. The most commonly used hydrophilic material is silica gel which can be dried and reused afterward.
Within these dehumidifiers, there is a rotating wheel of absorbent material. A fan is used to direct water over the material, and water is drawn out. A small dehumidifier heat pump is used to re-warm the air, and the re-warmed air is released back into the room. The moist air is then removed from the desiccant heat pump dehumidifier and drained outside.
The main advantage of these dehumidifiers is that they operate well in colder conditions or even subzero temperatures. They are also a lot quieter than other industrial models.
When Do You Need a Dehumidifier?
You need a dehumidifier when the relative humidity gets too high. In a residential environment, you should keep your humidity at 30-50%, but in a commercial or industrial building, you should generally aim to keep it below 70% humidity.
You can use a hygrometer to measure the relative humidity, and you should use a dehumidifier if you notice it getting too humid.
The telltale signs that your humidity is too high include:
- Increased condensation on cold surfaces
- Uncomfortable, heavy conditions
- Peeling paint and damage to walls and ceilings
- Visible mold and mildew
- Allergy and asthma being triggered more often
What Size Dehumidifier Do You Need?
The size of your dehumidifier isn’t the physical dimensions of the appliance, it’s the amount of water vapor it can remove from the air, and it’s measured in Pints Per Day (PPD). The higher the PPD, the more water it can remove from the air daily.
A number of factors influence the size you need, but generally, the more humid the conditions and the larger the space, the more PPD you need. Damp areas like crawl spaces, basements, or a pool room need a larger dehumidifier than a living room.
The most common type of home dehumidifiers will generally be able to remove 30-50 pints of water a day. There are larger models, but this is enough for most small homes. Industrial units can pull a lot more moisture from the air and can remove 150-250 pints of moisture a day.
You need to measure both the size of the space and the relative humidity level to determine what size of dehumidifier you need.
Dehumidifier Applications
Most people use dehumidifiers in their home, but there are lots of dehumidifier types suited to different tasks. Here are the most common industrial applications for dehumidifiers:
Food Industry
Dehumidifiers and humidifiers (usually desiccant humidifiers or dehumidifiers) help food last longer. Monitoring and regulating the humidity levels in the air helps food last longer without going off.
Cold Storage
Flowers, vegetables, fruits, and processed food are cooled and stored to last longer. These legally have to be kept in low moisture environments away from outdoor air, and dehumidification is used alongside air conditioners to remove excess moisture and keep these products fresh.
Defense and Military
Weapons, storage units, and military bases all need to be kept in good condition regardless of the environment around them. Dehumidifiers and an air conditioner system are used to maintain a consistent humidity and prevent mold or mildew from damaging vital supplies.
Pharmaceuticals
Medicines can be extremely hydroscopic and draw moisture in from the air. This can ruin the medicines and cause unwanted biochemical reactions. Dehumidifiers are used to maintain optimal conditions and protect pharmaceutical development and storage. They are also used to protect some medical equipment from water damage.
Batteries
Lithium batteries are used worldwide and have to be manufactured in a very low humidity space, or it can impact their performance. Dehumidifiers are used for industrial purposes to keep the humidity levels in check and protect the manufacturing process.
Electronics
Sensitive electrical components can’t be exposed to damp, humid conditions or can lead to corrosion and damage. Industrial dehumidifiers are used to keep humidity below 30% to protect sensitive electrical components during the manufacturing process.
Leather
Leather is another material that naturally absorbs water, which can lead to mold and mildew development. Dehumidifiers prevent mold and mildew, so the leather maintains its shine and unique scent.
Turbines
Dehumidification is used to protect turbines, condensers, boilers, and other machinery from moisture which can cause corrosion. Dehumidifying takes place throughout the manufacturing process and for storage.
Ice Skating Rinks
High humidity around an indoor skating rink can make it an uncomfortable environment and lead to fog. This can be annoying and dangerous if you’re trying to skate, but dehumidifiers keep the humidity low enough that it won’t form. Powerful industrial dehumidifiers need to be used in these indoor settings to keep the relative humidity below 10%.
Archives
Paper is easily damaged by moisture, but one of the key benefits of dehumidification is protecting important documents. They are used within indoor archives and museums worldwide to protect artifacts.
FAQs
Refrigerant vs Desiccant Dehumidifiers: What’s Best for You?
Refrigerant dehumidifiers are generally more efficient and extract more moisture than a desiccant model. However, desiccant dehumidifiers can operate in colder conditions (like basements and garages) and tend to be more portable units.
If you have very high humidity, you should use a refrigerant dehumidifier, but desiccant dehumidifiers can work well in tight spaces where the temperature is low.
How Long Do Residential Dehumidifiers Last?
A residential dehumidifier will last 5-10 years if properly maintained.
Is a Bigger or Smaller Dehumidifier Better?
The dehumidifier size should match the task, so it depends on the problem you’re dealing with. Large homes with a lot of humidity may need a whole-house dehumidifier with a high capacity, whereas a small area may only need a smaller unit. It’s worth measuring the humidity and choosing the right dehumidifier for your situation to get results and maximize energy efficiency.
Do Cheap Dehumidifiers Work?
Cheap dehumidifiers tend to have a lower capacity and can’t dehumidify as big an area. This can be fine to dehumidify a small space, but don’t expect it to last as long. If you have a lot of humidity to manage, you may need to invest in a more expensive but effective, heavy-duty model.
Conclusion
Dehumidifiers are really useful in a wide variety of settings, but you need to choose the right type to get the best results.
Hopefully, this guide has introduced the different types of dehumidifiers available, and you now know which is best for you.
References:
- https://www.hygroscopiccycle.com/hygroscopic-compounds/
- https://www.weather.gov/arx/why_dewpoint_vs_humidity#:~:text=The%20dew%20point%20is%20the,water%20in%20the%20gas%20form.
