How To Use Dehumidifiers: Everything You Need To Know
Written by: Marcin Haraszczuk
Date: 17 February 2025
Categories: Pumping & Drying, Pumps, How to Guides, How to Guides - Pumping & Drying

During winter, humidity levels rise and you might start seeing signs that there's too much moisture in the air in your home or place of work. If this is the case then a dehumidifier might be the answer to your problem.
In this blog, we will talk about everything you need to know about dehumidifiers from recognising when you'd need one to how to use them.
What is a dehumidifier?
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 too. 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 types and sizes of dehumidifiers for different situations. From compact models to larger industrial units, it's important to consider the features and benefits of each to determine the right option for your building.
Signs that you need a dehumidifier
There's a number of signs that will indicate that there's too much moisture in the air and you need a dehumidifier.
Look out for:
- Condensation on walls and windows
- Mould
- Musty smells
- Dust mites
- Peeling paint or wallpaper
- Rotting wood
Types of dehumidifier
Refrigerant/compressor dehumidifiers
These models are generally suited to more severe damp problems as they remove a greater volume of moisture. Instead of drawing in the air through a filter, compressor dehumidifiers pass it through cold coils similar to those in a refrigerator. Once the remaining air has been conditioned, it is blown back into the room, now moisture-free.
Features include:
- Durable unit that can last well over 10 years
- Highly energy-efficient and generally cheaper to run
- Good solution for air temperatures that exceed 15°C or 59°C
Refrigerant models are typically used in homes and small businesses as they are less expensive to run than other models. Refrigerant dehumidifiers are a popular type as they don't require special installation or maintenance.
Desiccant dehumidifiers
A desiccant unit removes moisture from the air by using a desiccant wheel made from hygroscopic substances that absorb moisture from the air. This type of dehumidifier is particularly useful after a leak or flooding as it can reduce the risk of further water damage and mould growth.
Features include:
- Minimal noise
- Small and light, making them easy to be move around
- Ideal for wine cellars and construction sites
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
When considering which dehum to buy, you should think about the following.
- Temperatures - for a colder room, use a desiccant dehumidifier and for warmer rooms you'll need a compressor dehumidifier.
- Size - opt for smaller models to reduce dampness and moisture in your home. For bigger issues, like a flood or a bad case of damp, you need a larger dehumidifier unit.
- Noise level - homeowners may not want a noisy unit compared to those on a construction site.
- Volume of air that needs to be dehumidified - larger rooms will need bigger units.
- Current humidity level of the room
- Air flow rate - the higher the airflow rate, the better the efficiency of the dehumidifier.
How to use a dehumidifier in 4 simple steps
Don't have time to read? Watch our instructional YouTube video below instead to see how to use one of our hire dehumidifier in your home or work place.
Step 1: Placing the dehumidifier
Typically, the most effective place to position a dehumidifier is in the centre of a room so the air can properly circulate around the unit. If the unit has a top-mounted air discharge, it can be placed against the wall. If you are using 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.
You'll need to make sure that the windows and doors are closed while the dehumidifier is operating and avoid putting the unit close to furniture as it can severely restrict airflow.
Check for dust and dirt in the room as this can alter how effectively the dehumidifier works. This is particularly important in manufacturing and construction sites where dust is regularly produced.
Step 2: Operating and selecting the right settings
Once the dehumidifier has been placed, turn it on and check the unit's settings.
Ideally, your home should have a humidity level between 30% and 50%. 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.
Carefully read the manual that comes with the dehumidifier so that you can adjust the settings correctly.
Leave the unit to do it's thing for the number of hours needed.
Step 3: Empty the water tank and clean the filter
Clean the dehumidifiers filters at least every six months to prevent dust and other particles from building up. The outside of the unit, especially around the intake and exit vents will also need cleaning.
You'll also need to make sure the water reservoir is emptied frequently and dehumidifier coils are functioning properly.
Step 4: Place an air mover to speed up the drying process
To maximise the performance of your dehumidifier and speed up the drying process, we'd recommend using an air mover. You should place the air mover in a suitable position that best reaches the wet area.
At HSS ProService, we have a selection of drying hire packs that has both a dehumidifier and a number air movers that vary depending on the hire pack chosen.