What Does a Home Dehumidifier Do (How They Work)?

Many people live in very humid climates; however, this can cause severe allergies and respiratory infections in some of them.

Excessive humidity doesn’t just affect you outside, either – if you live in a humid climate, it’ll be everywhere, including in your house.

Luckily, help is available!

A home dehumidifier removes excess moisture from your home’s air, thus significantly lessening the humidity level. It does this by capturing moisture from the air and converting it into a liquid before dumping it into a reservoir that is periodically emptied.

Home dehumidifiers provide many benefits, from health improvements to helping prevent unwanted pests.

Ready to find out what they can do for you?

Let’s dive into what home dehumidifiers do and how they work.

If you’d rather not use a dehumidifier to keep the humidity down in your home, you should read our article on how to Lower Humidity in 14 Ways (With No Dehumidifier Required).

The Basics of Home Dehumidifiers

All dehumidifiers are basically built the same way. There are five components to most dehumidifiers – the fan, the fan compressor, the reheater, the compressor cooling coils, and the reservoir.

The fan pulls in wet air from your home. The fan compressor works in conjunction with the cooling coils to ensure that they’re cold enough to cool the air and convert it to water through condensation.

The condensation is then deposited into the dehumidifier’s reservoir, and the air is reheated and released back into the room, free of excessive humidity.

Types of Dehumidifiers

There are two primary types of home dehumidifiers – refrigerant dehumidifiers and desiccant dehumidifiers.

Most dehumidifiers are the refrigerant type, and these are by far the most well-known.

As we explored when discussing the basics of home dehumidifiers, these work by cooling air and releasing it back into the room relatively moisture-free.

Desiccant humidifiers, while lesser-known, work just as well as refrigerant dehumidifiers. However, unlike refrigerant dehumidifiers, they don’t cool the air.

Instead, the air passes over an absorbent substance such as silica gel. The desiccant takes in the excess moisture, and the air is rereleased into the room.

Home dehumidifiers range from small portable dehumidifiers to whole-house dehumidifiers, which work with a home’s existing HVAC system.

There are also restoration humidifiers for more significant amounts of water, used in case of hurricane damage, which are essentially just giant portable dehumidifiers.

Signs You Might Need a Dehumidifier

• You’re uncomfortable. Discomfort is one of the most significant signs that you need to invest in a home dehumidifier. Humidity makes us humans feel extra sticky like you’ve been sitting in the hot summer sun all day.
• The house smells musty. That musty smell comes from excessive moisture in the air, which means humidity is hiding in your home.
• There’s mold or wet spots on the walls. This sign is somewhat apparent, but mold can only grow in damp areas. If you see mold, you’ve got a water problem. Of course, mold also grows where there are water leaks, so the cause is not always high humidity.
• Your windows are wet on the inside. Just as condensation forms on the outside of a cold drink can, humidity can cause condensation on the inside of your windows.
• Your cabinets are sticking, and your floors are creaking. When wood comes in contact with too much moisture, it swells. That swelling means you’ll get significantly more creaking and sticking than you usually would. This becomes more common as the seasons change.

How Humidity Affects Health

Humidity is more than just uncomfortable. Unfortunately, it also has a fair amount of health risks that come along with it.

Humidity makes the temperature feel hotter, leading us to overheat. It prevents our bodies from cooling down because we rely on the air around us to get rid of sweat.

When the humidity is high, the moisture from our bodies stays on our skin for long periods. This causes us to feel much hotter and for longer.

Humidity also causes our core body temperature to rise, leaving us in even more danger of overheating. This leads to dehydration and imbalances within the body.

Yes, high humidity hurts health, but it’s less common to see these symptoms in an indoor environment.

Respiratory Problems and Pests

High indoor humidity comes with plenty of health risks as well, however.

Humidity above the 50% range indoors can lead to multiple respiratory infections and bad allergies. This is especially true for those with weakened immune systems or preexisting breathing problems.

People who relocate from more arid environments to environments with high humidity almost universally benefit from a dehumidifier in their homes because their lungs just aren’t accustomed to the high amounts of moisture in the air.

Moreover, humidity attracts many pests that prefer damp conditions, further complicating health dangers.

More humidity means more disease-carrying pests such as cockroaches. This is one of the reasons more cockroaches are prevalent in Southern America and the Tropics.

Benefits of a Home Dehumidifier

Let’s get into the benefits of putting a dehumidifier in your home.

• Dehumidifiers get you more comfortable. Science says the ideal indoor humidity percentage is between 40% and 50%. Your home might stay at these levels if you live in an arid environment such as Nevada. Still, significantly more people live in humid climates, leaving the majority to fight the battle of high humidity.
• Dehumidifiers prevent mold and other fungal infections. Mold has various health problems; as I mentioned earlier, it needs damp areas to grow. This is almost entirely preventable with a home dehumidifier. Keeping your house at a comfortable humidity level for you keeps mold uncomfortable.
• Dehumidifiers help eliminate pests such as dust mites and cockroaches. No one wants to have pests swarming their home, and pests are significantly less likely to invade your space when the humidity levels are lower. These creatures love moist areas!
• Dehumidifiers help keep the air clean. Toxins flourish in high humidity, and while a dehumidifier doesn’t do a better job than an actual air purifier, it will undoubtedly help with the problem.
• Dehumidifiers protect the structural integrity of your home. Without moisture, most things deteriorate much slower. In high humidity environments, the walls, floors, and more end up swelling breaking, and making way for other problems.

To understand how a dehumidifier protects against mold in your home, see our article on the subject here.

An In-Depth Look at How a Home Dehumidifier Works

Let’s get into the nitty-gritty of how home dehumidifiers work. There’s a good bit to this, so let’s break it down into more manageable sections.

The Refrigeration Cycle

Interestingly, the components within a home dehumidifier parallel the components in a window air conditioning unit. This is primarily because both use what is known as the refrigeration cycle.

The refrigeration cycle works by pulling in room temperature refrigerant in its gaseous form and compressing it.

During the compression process, the refrigerant is heated, perhaps going from 70 to 200 degrees Fahrenheit (21 to 93 degrees Celsius), and moves on through the system.

At this point, the refrigerant needs to be cooled back down, so it is sent over a series of copper coils, known as cooling coils, in the condenser. These cooling coils work in conjunction with various fins to help dissipate a lot of the heat.

During the cooling process, the refrigerant gets converted into liquid.

Once it’s converted into liquid, the refrigerant is sent through a metering orifice (or expansion valve), which works similarly to a spray bottle converting liquid into a mist.

In the case of refrigerant, it is converted into a mixture of liquid and vapor. This process cools the refrigerant down to an even lower temperature. For example, it may reach 20 degrees Fahrenheit (-7 degrees Celsius).

The refrigerant then moves on to the evaporator, where it changes phase to vapor. Ambient air is blown across the evaporator coils to cool it down.

As it cools, much of the moisture in the air condenses onto the evaporator coil, thus reducing the humidity of the air.

The Refrigeration Cycle in a Dehumidifier

Unlike an air conditioner which features a division between the cooling coils and misting area for the refrigerant, a dehumidifier has all of this in one section.

Essentially, the refrigeration cycle in a dehumidifier is used to cool down the coil in the evaporator. A fan blows room temperature air across the cold evaporator coil, cooling it quickly and causing the moisture in the air to condense onto the coil, dripping off into a reservoir or drain.

When air is released back into the room, most of the moisture has been removed, and the atmosphere is much less humid as a result.

The Parts of a Dehumidifier

The bottom of the dehumidifier contains a compressor. Inside the compressor is a motor head that drives the compressor and some temperature protectants.

Above the compressor, you’ll find the cooling and heating coils. This is where the air passes through to begin the process of removing the moisture.

To the side of the coils, you’ll find the metering orifice, which is essentially just a tiny metal tube for the liquid refrigerant to flow through and be misted out.

The moisture removed from the air falls into the drip pan below. Once it’s full, you’ll dump it, and the dehumidifier will continue to do its thing.

Tying It All Together

To tie all these parts together, let’s do a quick review. The dehumidifier uses the refrigeration process to remove moisture from humid air.

Air and room temperature refrigerant is sucked into the dehumidifier, and the gaseous refrigerant gets compressed and also gets hotter.

It is then passed through the copper coils to cool down slightly and later put through the metering orifice to be cooled down to very low temperatures, often below freezing.

The refrigerant is then misted into the cooling coils that the ambient air is blown across.

The cold coils cause the air to let go of its moisture because the moisture can’t stay in gaseous form when the air is so cold. The moisture condenses onto the cools and is released into a drip pan below. The air is then rewarmed and released back into the room, relatively moisture free.

Check out this video if you’re interested in a more in-depth look at how home dehumidifiers work.

Some Other Things You’ll Want To Know About Dehumidifiers

If you’re thinking about purchasing a dehumidifier at this point, there are some things you’ll want to be aware of.

First, most normal home dehumidifiers are going to be smaller and portable. This is a benefit for you because you can move it around. On the downside, however, these only cool small spaces.

If you’re using it to dehumidify your entire home, you might need multiple portable dehumidifiers throughout the house. In this case, it might be best to look at a whole house dehumidifier.

Second, dehumidifiers come in multiple sizes with reservoir tanks that hold various amounts of water. To dehumidify a larger room, you can purchase a slightly larger dehumidifier. The opposite goes for a smaller room.

Third, dehumidifiers aren’t always expensive. There are a ton of budget-friendly options out there.

Generally, you can get a decent home dehumidifier for around $100 to $150. Of course, dehumidifiers with many more features range upwards of $500, but these aren’t necessary for your basic moisture removal needs.

Finally, dehumidifiers come with all kinds of options to suit your needs.

These added features include automatic shut-offs, continuous drainage hoses instead of reservoirs, automatic defrost mechanisms, and automatic restarting after a power outage.

Conclusion

Home dehumidifiers are well worth the money. They’re an excellent way to stay healthier in damp, high-humidity environments and are extremely helpful in controlling pests and allergies.

Sometimes, when we live in high-humidity environments, we become so accustomed to the excessive moisture that we forget that it’s significantly healthier to breathe drier air.

Please give it some thought, and I look forward to hearing about how your dehumidifier helped you beat the heat and humidity.

Already have a home dehumidifier and wondering how long it is likely to last before it breaks? We’ve got the answer for you in our article, “How Long Do Dehumidifiers Last? (Revealing Whole House and Standalone Lifespans)“. Check it out!