You’ve probably heard about humidifiers and dehumidifiers, and how important they both are when it comes to the quality of your indoor air.

But it’s sometimes a mystery as to how these work and how they differ.

How are dehumidifiers different from humidifiers?

Basically, a dehumidifier decreases the level of humidity in the air, while a humidifier increases it.

There are many good reasons to invest in one of these appliances.

In this article we’re going to focus on dehumidifiers and when they’re worth purchasing, as well as how they work.

How Does A Dehumidifier Work?

How Does A Dehumidifier Work

A dehumidifier is an appliance that basically draws out the humid air in a room and then sends it back much cooler and drier than it was before.

Here’s how it does that.

  • A dehumidifier contains coils and a fan and works by sucking warm air currents from inside the home. These pass through the fan into the refrigerated coils.
  • The warm air moves through the unit’s refrigerated coils, which contain a circulating coolant. The air cools down so that it produces condensation because the moisture becomes liquid water.
  • This condensation accumulates and enters a storage tank. Since the moisture has been effectively removed from the air, the air can move over the hot compressor unit.
  • It becomes warm so it can be sent back into the home via a grille in the unit’s design.
  • The moisture which was produced moves into a collecting tray or tank in the machine, as we mentioned earlier. However, the machine also contains a plastic float which rises as the tray fills with moisture.
    When the tray has become full, this float activates an electric switch so that the fan can be turned off. It also switches on an indicator light – this light is what lets you know when the machine has to be emptied.

Dehumidifiers can reduce the air’s moisture by about 30 to 50 percent, and most will have a meter included in their design that measures the indoor air’s relative humidity.

This enables you to ensure that you have the amount of humidity you want.

Do You Need A Dehumidifier In The Home?

Frigidaire Dehumidifier

You might not know if you require this appliance in the home, so here are some good reasons that should make you purchase one.

  • You find that your allergies stick around for longer than the allergy season. A dehumidifier can help to dry out the air which will keep allergy triggers at bay.
  • You can smell dampness in an area of your home, and/or your clothing smells damp.
  • The indoor air of your home is usually muggy, as it’s filled with water vapour.
  • You have seen more unwanted pests in your home, such as moths, spiders, and cockroaches.
  • You might not have allergies, but you have constant respiratory illness symptoms, such as a runny nose or cough.
  • You’ve noticed mold in areas of the home, which signify damp.
  • Your home is really dusty. Do you feel like you’re always cleaning your home or that you’ve got an infestation of dust mites?
    That can be frustrating, but a dehumidifier can help to combat the problem because it decreases how much dust is in your home. Bear in mind that dust mites love humidity, so by removing the excess humidity in your home you can effectively eliminate these mites.
  • You’re running your air conditioner a lot. By drying out the air, a dehumidifier can increase the effectiveness of your air con, therefore saving you money when it comes to your energy bills.

Why Is High Humidity Bad For Your Home?

High Humidity

You might not have thought about the humidity in your home’s indoor air, but you really should.

If the humidity is too high, this can cause a wide range of problems, such as rusting in your electronic equipment, and an increase of bacteria, mites, fungi, and viruses which can make you sick.

The ideal humidity level that should be in your home is between 40 and 60 percent.

What Are Potential Drawbacks Of Using A Dehumidifier In The Home?

While you might think drying out the air is a good thing, sometimes it can cause problems of its own.

These include the following, of which you should be aware:

  • If you live in a dry region, you probably won’t require a dehumidifier otherwise the air will become too dry. This can lead to infections, asthma, eye irritation, and other problems.
  • If you’re prone to conditions such as pneumonia, it’s worth bearing in mind that dehumidifiers can make it worsen because the air will be too dry.
  • Indoor air that’s too dry can affect your skin, such as if you have a condition like eczema.
  • Since using a dehumidifier will dry out the air, this could lead to dehydration so you need to ensure you drink a lot of water.
  • If you battle with congestion and/or a dry cough, it’s worth consulting your doctor before purchasing a dehumidifier as this appliance could make your symptoms worse.

What To Look For In A Dehumidifier

Ivation Dehumidifier

If you want to purchase a dehumidifier, it’s important to look for a quality appliance that will give you all the essential features you need.

Here are some of the best features.

  • Pint capacity. What’s the pint capacity of a dehumidifier?
    This is basically how much moisture, measured in pints, that a dehumidifier will be able to remove from your indoor air within 24 hours. Appliances that have a pint capacity which is less than 70 pints can be used for the home, while those with greater pint capacity are more suited to industrial or commercial purposes.
  • Collection tank shut-off. Dehumidifiers will contain a tank that enables you to easily get rid of the water they’ve collected. It’s good to look for an appliance that will shut off automatically when its tank is full, so you know to empty it.
  • A humidistat measures relative humidity and then sends the data to the dehumidifier so that it can make adjustments to it. This enables you to choose the setting for your dehumidifier so that you can maintain a healthy level of humidity.
    While you might think this comes standard in dehumidifiers, some appliances require you to buy humidisats separately, so that’s something to bear in mind. It’s obviously more convenient to purchase a dehumidifier that contains a humidistat.
  • Operation in low-temperature areas. You will see this feature in dehumidifiers that are appropriate for environments which have low temperatures, such as crawl spaces.
    If you want a dehumidifier for this type of area in your home, then it’s worth checking that the appliance will be able to work in temperatures that are lower than 30 degrees Fahrenheit (-1 degree Celsius).
  • Manual or electronic controls. You can find dehumidifiers with manual or electronics controls. Manual appliances will have a dial that you will use to change its settings, while electronic ones will make use of buttons.
  • Auto-restart feature. This is a useful feature to have as it will ensure that if there’s a power interruption at your home, the appliance will start again automatically when the power is restored and your settings won’t be lost.
  • You must bear in mind that some dehumidifiers can be quite noisy, so it’s always good to look at how many decibels the dehumidifier produces.

How To Test The Humidity Level In Your Home

Dimplex Dehumidifier

Before you purchase a humidifier or dehumidifier, it’s important to know what the humidity level is in your home, otherwise you can do the opposite of what you were hoping to achieve.

Here’s a simple humidity test you can do.

Put three ice cubes in a glass, add some water, and stir it. Leave it in the room for a few minutes. If you don’t notice moisture forming on the glass exterior, the air is too dry.

You could therefore benefit from a humidifier in the home. On the other hand, if you can see condensation on the glass exterior, that’s a sign that the humidity is high so you could do with a dehumidifier.

Related Questions

How much does it cost to run a dehumidifier?

An average dehumidifier will cost three to four pence per hour if you’re running it constantly.

Does a dehumidifier increase the heat in your home?

A dehumidifier will increase your home’s indoor heat. You might be able to increase the temperature by between five and 10 degrees, but this will depend on the room size.


If you’re battling allergies or your home is prone to damp problems, then a dehumidifier can be useful to own.

In this article, we’ve looked at everything you need to know about dehumidifiers, such as when it comes to how they work as well as their pros and cons.


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