Heavy air, sticky skin, frizzy hair … all signs that mean high humidity. If you live near the equator or near the ocean, you probably deal with your fair share of damp air. Humidity not only makes everything feel weighty, it can affect our mood. Even worse, when the humid air permeates our homes it can affect the whole family.
Those living in a humid climate and allergy sufferers are among many people who seek to purchase a dehumidifier or own one already that helps relieve their symptoms. There are many benefits to owning a dehumidifier, not the least of which is helping to allay your allergy symptoms. These magic machines take moisture out of the air, prohibiting the growth of mold and mildew: a necessity when living in coastal or equatorial regions.
But exactly how do dehumidifiers work?
Understanding Humidity
First, let’s understand what humidity is, as most people are referring to relative humidity when they talk about the steamy weather. Absolute humidity is the total mass of water vapor in a given volume of air, so relative humidity is the ratio of current absolute humidity to the highest possible absolute humidity. The hotter the air, the more moisture it can hold. As the percentage of relative humidity increases, the more moisture the air contains, and when it hits 100% the atmosphere releases the moisture, which is also known as rain or snow.
Obviously it doesn’t rain in your home, but when it is raining outside it can feel like one hundred percent humidity inside. When you have excessive moisture in your home, it can cause more problems than just a little heaviness in the air. The growth of mold and mildew can make you and your family ill, as well as be a haven for pests like silverfish or centipedes. It can also weaken your home’s structure, causing rot in wood beams and studs.
The Basics of Dehumidifiers
In the summertime, it is common to drink iced coffee or iced tea, depending on where you live. If you leave your cup in the heat for any length of time, it begins to sweat. When the hot air touches the cold surface of the cup, it reduces the temperature of the air and releases the moisture because cooler air cannot hold as much water as hot air.
This process is similar to how dehumidifiers work. There are four main parts to a dehumidifier: the fan compressor, the reheater, the compressor cooling coils, and the water reservoir. A fan pulls the air from your home into the dehumidifier, passing it over the coils. The compressor cooling coils are the “iced coffee cup,†cooling the air and taking out the moisture. The fan compressor acts in a similar way to an air conditioning unit, forcing a gas like freon through the cooling coils of the dehumidifier.
The reheater then warms the dry air back up before releasing it back into your home. The water reservoir catches the condensation (excess water) on a removable tray that you must empty periodically, depending how frequently you run your dehumidifier. Some models come equipped with a hose attachment so you can set it up to empty directly into a drain.
Air Conditioners versus Dehumidifiers
You may see the similarities between air conditioners and dehumidifiers because of the process in which they both cool the air which reduces the moisture levels. An air conditioner can reduce the humidity in your home; however, because it doesn’t have a humidistat, it won’t turn on when the relative humidity is too high, only when the temperature climbs higher.
A humidistat measures the relative humidity in your home and has two parts, the sensor and the relay amplifier. When the moisture levels increase, the sensor is triggered, and the relay sends a message to the dehumidifier to turn on. Conversely, when the humidity drops, the sensor will stop triggering the relay and the humidifier will turn off.
Unlike a dehumidifier, the air conditioner will not reheat the air it exhausts into your home, which is why it keeps your house cool. A cooler house naturally has less humidity, but when your home reaches the temperature you have the air conditioner set to, it will shut off regardless of how humid it feels. As your house warms back up with the air conditioner off, the humidity increases as well, making your home feel warmer than the temperature reads on the thermostat.
Types of Dehumidifiers
There are a couple of varieties and even more sizes of dehumidifiers, so understanding how they work and what is most effective for your needs is important. The two main types are the refrigerant dehumidifier and desiccant dehumidifier.
The desiccant dehumidifier draw in the air and run it through a desiccant such as silica gel which absorbs the moisture. You know the packets of beads you find in a new pair of shoes or purse? Yep, that contains silica, and it keeps clothing and other sensitive materials free of moisture.
The main difference between the two types is that desiccant dehumidifiers are better for smaller spaces, and tend to be cheaper, lighter models. They work great in small spaces that have leaks or have been affected by natural disasters. Their mobility allows for ease of transport, which is ideal in disaster relief situations. Another factor to consider is that they work in all climates, no matter the temperature.
The refrigerant models are better for heavy-duty work like floods, wet basements, and larger spaces. These are more frequently used in commercial settings and are actually ineffective at temperatures below 40 degrees. Evaluate your needs before making a commitment to purchase.
Cost of Operation
As far as power usage goes, an average dehumidifier will consume more energy than your refrigerator, but less than an air conditioner, which can chew up 300 kilowatt hours per month. However, because keeping your home drier will make it feel cooler, your air conditioner may run less frequently, thereby saving you money on the long run.
Also, there are Energy Star rated dehumidifiers that will consume less energy overall, such as the Aprilaire 1870F. Equipped with a humidistat, it will only run when it senses too much humidity in the air. Running it only to what level of moisture you have it set to can reduce the energy consumption and lower your electric bill.
Benefits Outweigh the Cost
Deciding whether or not you need a dehumidifier is a fairly easy assessment. Take a look around your home and note any areas that have moisture stains or weakened wood. Check for mold along drywall and mildew build-up in the bathroom. Other subtle clues that tell you that a dehumidifier is needed are sticky doors and windows, and creaky floors. Moisture causes wood to swell and make different noises when it is damp.
Mold can cause serious health problems, especially in children and seniors. If spores are inhaled, it can lead to respiratory infections and more serious problems requiring medical treatment. Using a dehumidifier not only reduces and stunts the growth of mold which will create a better air quality over the long term for you and your family. Pests are drawn to damp and dark places, just like mold. Using a dehumidifier will keep silverfish, centipedes, and other pesky insects at bay.
Now that you have a better understanding of what dehumidifiers are, how they work, and the many benefits, you can see that they are worth the investment. The benefits definitely outweigh the cost, provided your quality of life will improve from having one in your home.
