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Dehumidifiers vs humidifiers – what’s the difference?

Central heating giving you a headache? Sick of bathroom mould? Invest in a dehumidifier (or humidifier) – just don’t get them mixed up

Depending on the time of year, you may notice that too much or too little moisture in the air in your home is becoming an issue. This can cause problems like headaches, excess condensation, dampness and even mould.

Thankfully, investing in one of the best dehumidifiers or best humidifiers can help to make a huge difference and transform your standard of living.

But which one is best? Should you be looking for a dehumidifier or a humidifier? Well, we’ve tested both to help you choose the best option (and model) for your needs.

Dehumidifiers vs humidifiers: What’s the difference?

While both dehumidifiers and humidifiers are designed to deal with moisture levels in the air, one adds moisture (humidifier) while the other (dehumidifier) removes it.

According to experts, the natural humidity in a home should be somewhere between 30% and 50%. You’ll need a hygrometer or indoor humidity monitor for a precise reading – but if you don’t have either of those gadgets to hand, you can also use a couple of ice cubes in a glass.

This simple test will provide a rough estimate of whether the air has too much (or not enough) moisture. Simply take a glass of water and place four or five ice cubes in it, then leave the glass in the room where you want to check the humidity level. Wait for around ten minutes before checking it.

If there’s condensation on the outside of the glass, that means the room has a relatively high humidity level and there’s too much moisture in the air. If there’s no condensation on the glass at all, this could indicate insufficient moisture in the air.

If the air in your home has over 50% humidity, that’s when you should consider using a dehumidifier to remove excess moisture. Whereas, if humidity levels are below 30%, a humidifier is the best option to add moisture back into the air.

As you’ve probably realised by now, it’s important not to get the two very similar terms mixed up when trying to decide which one is the best option.

Dehumidifiers: Pros and cons

A dehumidifier is particularly helpful during the warmer, more humid months of the year as it can help the air to feel less clammy in the summer. However, your home will benefit from using a dehumidifier all year round.

Everyday tasks such as drying your clothes indoors, taking a steamy shower or cooking, can cause condensation which quickly turns into a build-up of moisture which can cause a range of problems to emerge, ranging from damp to mould – and even dust mites! These issues can trigger respiratory conditions such as asthma and allergies, which is why it’s so important to keep on top of excess moisture levels in the air in your home.

By reducing the water content, dehumidifiers can make the air easier to breathe, which is especially handy during humid weather. They can also prevent musty odours and condensation, which again could be an early indicator of mould.

best dehumidifiers lead image: Meaco dehumidifier on wooden floor

Using a dehumidifier can also help to speed up laundry drying time. So, if you have a lot of washing to dry indoors, running a dehumidifier can help to draw the moisture out of damp clothes, bedding and even towels, which will save you time and money if you’ve previously been drying your washing on a radiator or over a heated drying rack. 

It’s also worth noting, if you’re a DIY fan, that using one of these devices can also speed up the drying time of wet paint and plaster too (although most water-based emulsions dry in a couple of hours these days).

A dehumidifier can also help to stop books, paperwork, magazines and artwork from being damaged by moisture. And there are certain pests – such as ants, beetles and termites – which find themselves drawn to moisture. If you’ve noticed a problem with any of these insects, running a dehumidifier will help to draw out the moisture from any suspect woodwork and make these critters less inclined to stick around.

Some of the drawbacks of owning a dehumidifier are that certain models can be quite large and bulky, with the constant “burring” noise also being an issue. They are also a lot more expensive to buy than humidifiers. 

It’s also worth considering that if you like to keep your windows and doors open, particularly in the warmer months, doing so will stop a dehumidifier from working correctly. For maximum efficiency, all windows and doors must be shut for a “closed system” of air – much in the same way that air conditioning in a car only works effectively if all the windows are shut.

Humidifiers: Pros and cons

Humidifiers, on the other hand, add moisture back into the air. They’re also really handy to have around during cold and flu season, or if you find yourself struggling with a dry or bloody nose. This is because viruses can thrive in dry air, so a good humidifier stops your home from being somewhere where they can thrive or linger.

If you have houseplants, you may also want to invest in a humidifier, especially if the varieties you own are normally grown in a humid environment. 

You may even notice that running this kind of device can make the room feel a little warmer as it helps remove the chill in the air. This means you won’t need to switch on the heating quite as regularly, which will save money in the long run.

The only specific downside is that this technology requires far more regular cleaning than a dehumidifier. The reason? Bacteria and fungi can thrive in a humidifier if it’s not properly cleaned and maintained. And if you don’t keep on top of that, those particles can be released into the air alongside the moisture.

Also be aware that if the room you’re using a humidifier in already has sufficient moisture, adding even more to the air can cause the kinds of problems that you would need a dehumidifier for, such as mould and mildew.

Dehumidifiers vs humidifiers: Which is cheaper to use?

The exact cost of a dehumidifier or humidifier will depend on a few different things, such as how large or energy efficient the model is. It will also cost more to run the appliance in a larger room than a smaller space.

Typically, it’s more expensive to run a dehumidifier than a humidifier. This is because a dehumidifier is working constantly to eliminate excess moisture in the air, whereas a humidifier only adds moisture to the air when it’s dry.

Dehumidifiers also tend to be larger, which means that they require more energy to work. But the benefits of using both types of technology may outweigh any costs.

Finally, while a humidifier may be far cheaper to run than a dehumidifier, it’s important to understand which one will work best for you (and the issues you’re facing in your home). Just because one is cheaper than the other doesn’t mean that it will automatically be the most suitable choice for your needs.

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