Dehumidifier/Building Dryer

How to Guides

How To Use Dehumidifiers: Everything You Need To Know

Updated August 31st 2023

Is your property feeling damp and dreary? Do you need to get rid of that musty smell in the air? Are you worried about mould and mildew growing in your home or workplace? Do you have a freshly plastered room that isn’t drying out? Have you recently experienced a leak or flooding?

If so, then a dehumidifier might be the answer.

If you're looking at using a dehumidifier at home or work, you may have some questions such as:

  • What is a dehumidifier?
  • How do dehumidifiers work?
  • How to choose a dehumidifier?
  • How do I use a dehumidifier?
  • Where can I use a dehumidifier?
  • Will a dehumidifier get rid of damp?
  • How long does it take for a dehumidifier to dry out a room?

In this guide, we take you through the whats, whys, wheres and whens of dehumidifiers so that you can make the right choice and get the most out of the device.

If you're looking for a fast solution to moisture at home or in the workplace, hire a dehumidifier from HSS today!

What does a dehumidifier do?

Dehumidifiers are appliances that remove excess moisture from the air. They're designed to help reduce mildew and mould, which can trigger allergy symptoms and cause respiratory problems. They can also help prevent damage to wooden furniture and other items in your home by reducing the amount of moisture in the air. 

There are various different types and sizes of dehumidifiers for various situations. From compact units to larger industrial units. It's important to consider the features and benefits of each to determine the right option for your building.

The two main types of dehumidifier

Here are the main types of dehumidifiers used for moisture removal in domestic, industrial and commercial settings.

Refrigerant/compressor dehumidifiers

These models are generally suited to more severe damp problems and can remove a greater volume of moisture. They are:

  • Powerful and suitable for poorly isolated buildings
  • Durable unit that can last well over 10 years
  • A highly energy-efficient option that is generally cheaper to run
  • Good solution for air temperatures that exceed 15°C or 59°C
  • These models are generally suited to more severe damp problems and can remove a greater volume of moisture.

One of the most typical types of dehumidifiers that you will encounter on the market is a refrigerant dehumidifier. Refrigerant models are typically used in homes and small businesses, as they are less expensive to run than other models. The primary benefit of a refrigerant-based dehumidifier is that it does not require special installation or maintenance.

Like air conditioners, they work by removing warm air from your home, but they do not expel it outside.

In compressor dehumidifiers, humid ambient air is drawn across cooling coils by a fan. As a result of these cold metal pipes, the air's water instantly condenses. Water is then condensed into the reservoir (or down the hose pipe if you have one), while cold air is mixed with heat exhaust and expelled.

Desiccant dehumidifiers

A desiccant unit removes moisture from the air by using desiccant material. The use of a desiccant dehumidifier is particularly useful after a leak or flooding - it can reduce the risk of further water damage and mould growth. They are:

  • A quiet dehumidifier that produces minimal noise
  • Commercial dehumidifiers often used to maintain temperatures and air quality
  • A small and light option good for portability
  • Ideal for wine cellars and construction sites 

As opposed to compressor dehumidifiers, which have been much more common over the last few decades, desiccant dehumidifiers are quite different. Let's take a quick look at how they work to understand their differences.

Instead of drawing in the air through a filter, compressor dehumidifiers pass it through cold coils similar to those in a refrigerator. Water condenses in the coils and drips down into a separate section of the unit as the air passes through. Once the remaining air has been conditioned, it is blown back into the room, now moisture-free.

Where temperature control is vital, such as in industrial spaces preparing food, a desiccant dehumidifier is an ideal and reliable solution.

How to choose the best dehumidifier for your space

Now that you have a basic understanding of the features of the two main dehumidifiers, it's time to compare them against your needs and requirements. It's difficult to differentiate between the two and select the right solution, so we're here to help. 

Put simply, the best way to look at the difference is:

  • Use a desiccant dehumidifier for colder rooms
  • Use a compressor dehumidifier for warmer rooms

To analyse the two options on a deeper level, you should evaluate:

  • The required noise level (homeowners may not want a noisy unit whereas construction sites may be more than used to noisy machinery!).
  • The volume of air that needs to be dehumidified based on the size of the room. 
  • The current humidity level of the room
  • The air flow rate - the higher the airflow rate, the better the efficiency of the dehumidifier

What size dehumidifier do you need?

Larger scale damp and moisture problems can be addressed with larger dehumidifier units - both refrigerant-based and desiccant-based. It might be a better idea to opt for a smaller, portable model if you are just looking for something to reduce dampness in your home. If you want to focus the attention of your dehumidifier on another area in the home, some dehumidifiers are pretty compact, making it easy to relocate them.

Consider the room size and conditions

Room dehumidifiers shouldn't just be selected solely based on their capacity and size. Your room's conditions should also be considered when finding the best solution.

Take a look at the conditions of the space. If there's a minimal amount of dampness in the room(s), you may be better off choosing a smaller portable dehumidifier. You'll identify the right size for your space by looking at the rated capacity for your square footage.

On the other hand, a wetter space will require a large capacity unit in order to effectively reduce humidity and dry the area quickly. If you need help figuring out the humidity level of the space, try using a hygrometer to monitor it.

White modern looking compact dehumidifier

How to use a dehumidifier in 3 simple steps

Are you looking to hire equipment from HSS and not sure how to use it? You’re not alone. Dampness affects many homeowners and business owners, particularly after water damage, and it can be extremely difficult to get rid of without the right equipment.

That’s why we have put together this step by step guide on how to use a dehumidifier for the best results when eliminating mould and excess humidity from your home.

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Step 1: Placing the dehumidifier

Firstly, it’s worth noting that the most effective place to position a dehumidifier is in the centre of a room. This allows the air to circulate properly around the unit. The only time when this positioning can be disregarded is if the unit has a top-mounted air discharge. In this case, it can be placed against the wall. 

  • Make sure that the windows and doors are closed while the dehumidifier is operating.
  • If you are operating the dehumidifier in a particularly large space, it should be placed in close proximity to the moisture source to maximise the potential of the unit. 
  • Avoid putting the unit close to furniture - it can severely restrict airflow!
  • Look at the surroundings and check that there are no sources of dust and dirt. This is particularly important in manufacturing and construction sites where particles like this are regularly produced. These materials can affect the effectiveness of the unit.

Step 2:  Operating and selecting the right settings

Once you've plugged your dehumidifier in and placed it in a suitable place, locate any settings, buttons and the LED screen. Ideally, your home should have a relative humidity level between 30% and 50%. Your home may suffer from extreme dryness if these levels are below this range, while bacteria may flourish if these levels are above this range.


You can monitor the humidity level either by using a hygrometer or by using the LED screen on the control panel of your dehumidifier. Manual dehumidifiers can be switched to lower settings when the humidity level drops.

If you have an automatic dehumidifier that has energy-saving settings, simply set it to its highest setting and leave it to switch to its most efficient setting as the humidity level declines.

You should carefully read the manual that comes with the type of unit you hire, some come with auto-adjust settings that change as the temperature/humidity changes. Some also have a timer on them to ensure the device is not running for too long unnecessarily.

Dehumidifier console LED screen

Step 3: Empty the water tank and clean the filter

In the event your dehumidifier has a continuous drainage function that you'd like to use, attach the hose according to the instruction manual.

In gravity-driven systems, run the hose down; in motorised systems, run it up. Keep the hose straight and free of kinks.

You can force water down by cutting a small hole about 30cm away from the dehumidifier in the top of the hose if the water is not flowing through the hose properly.

Dehumidifiers must be maintained and cared for regularly to function properly. When you maintain the unit and allow it to properly dehumidify the air, the unit will perform better. Don't forget to:

  • Clean the filters at least every six months to prevent dust and other particles from building up
  • Clean the outside of the unit, especially around the intake and exit vents
  • Make sure the water reservoir is emptied frequently 
  • Make sure your coils are functioning properly  

Step 4: Place the air mover to speed up the drying process

Our drying packs at HSS come with an air mover. We suggest using this to maximise the performance of your dehumidifier and speed up the drying process. You should place the air mover in a suitable position that best reaches the wet area. Fortunately, the moveable outlet enables users to adjust direction where required.

6 reasons why you might need a dehumidifier

Aside from the health benefits and general improvement of air quality, dehumidifiers are the perfect solution in many scenarios. Not sure if you need one? Take a look at the reasons below to determine whether or not one of these units would be a good for your building or room.

During autumn and winter months

As the temperature drops outside, you may notice that your home's level of humidity increases. You might even notice condensation on windows or a musty smell in your basement. High humidity levels can cause mould and mildew growth, which can be unhealthy for you and your family.

During colder temperature, water vapour in the air condenses into liquid droplets when it comes into contact with something colder than itself - like your windows or walls. This happens because as the temperature continues to drop and the air becomes even more saturated with water vapour, the amount of condensation increases.

So even though it may be dry outside, that doesn't mean that there won't be some moisture inside your home.

Plus, a dehumidifier can often help to keep the cold out, thus reducing your heating bills!

Dust mite elimination

Dust mites are present in many homes in the UK, no matter how clean your house might be. If they do become troublesome and trigger allergy symptoms, then you may be desperate to get rid of them. They thrive in warm, humid rooms, and are one of the leading causes of allergies. They’re also notoriously difficult to get rid of: if you don’t treat your home for them, they can remain active for up to six months after vacuuming.

  • Dust mites live in humidity levels between 70 to 80%. A dehumidifier operating between a 30 to 50% range of humidity will therefore help to eliminate those pesky mites!

That’s why it’s so important to use a dehumidifier! By removing excess moisture from the air, you’ll make it much less suitable for dust mite growth and therefore much easier to keep them at bay.

Water damage from flooding

After a flooding, drying and pumping equipment is essential in recovering the state of the building. Dehumidifiers are just one of the ways you can dry the area quickly and efficiently. 

Removing excess water is paramount to prevent the growth of mildew and mould, this is best done with a high capacity dehumidifier as soon as the event has happened. Commercial dehumidifiers handle bigger areas and reduce humidity levels rapidly in around 24 to 48 hours (room size dependent).

The additional moisture in the air is removed by the dehumidifier unit. This causes it to condense within the unit for safe disposal, ultimately eliminating or reducing dampness in the affected building.

Tackle damp and mould smells

Having a lingering musty smell in the home or workplace can be a telltale sign of mould and damp growing within the building. This could be present in cellars or basements. The route of the cause should be detected promptly, as it could be a structural issue or a blocked vent. 

Once the problem has been identified and eliminated, the smell can be drastically reduced with a dehumidifier. Some ranges include a handy carbon filter designed to remove musty odours.  

Hiring a humidifier for your home or office with HSS

Dehumidifiers are an essential tool for improving indoor air quality and eliminating dampness, mould and excess moisture. If you’ve got a damp or mouldy space in your home or office, then it’s time to hire a dehumidifier from HSS!

We have suitable units for commercial spaces, offices, homes and construction sites. Simply explore our equipment available to hire and place your order. We’ll ship it out to you as early as the next day!

If you need any help with your dehumidifier hire, please don’t hesitate to speak to a member of our friendly team at your local HSS branch.

HSS Pump dehumidifier 56734 in a flooded basement
Author - Marcin Haraszczuk

About the Author

Marcin Haraszczuk

Marcin is a member of our E-Commerce Team. He mixes creative flair with analytical thinking, has a knack for DIY and is always seeking ways to broaden and share his knowledge.

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