Refrigerant Dehumidifiers

Delonghi Des12 Slim Review

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UPDATE: The Des12 has been superseded by the more impressive DEX12, also by Delonghi. It features Aria-Dry technology, much lower operating noise and a host of improvements. You can read our full review of the DEX12 here.

The Delonghi Des12 is very simple in its appearance and has an even simpler control panel. So, it might surprise you to learn that it has a number of very well thought out features, which belies its basic looks, and pleasantly surprised us.

De'Longhi DES12 Compact Dehumidifier - 12 Litre

Des12 Slim – Overview

The Delonghi Des12 is something of an acquired taste, at least aesthetically speaking. It has a rather unique look with vents on either side of the front of a very angular case and measures just 48.5cm wide by 37.5cm deep by 19cm high. The positioning of these vents is not purely for aesthetic reasons – they serve a very useful purpose.

Delonghi refers to this as ‘bilateral airflow’ and it allows more air to be drawn into the unit even when it is close to walls. This will allow you to very discretely tuck the dehumidifier nicely away in a corner, out-of-sight, to do its job.

In fact, you need only leave around 5-10cm at the back of the unit to allow it to function correctly. To put this into perspective we have seen some dehumidifiers such as the Delonghi DNC65 which requires a minimum of 20cm clearance around the entire unit. So, it is possible to see just how discrete this little unit can be.


The Delonghi Des12 weights only 9kg, making it very light for a refrigerant/compressor dehumidifier which usually weigh at least 10-11Kg plus. The top of the machine also sports a robust, folding carry handle so you can easily lift the unit with one hand while moving it.

Delonghi have also provided a set of 4 castors which you have the option of plugging into the base of the unit. To fit the castors you need to remove four rubber bungs at the base of the machine before inserting the castor pins. The bungs can be a little stiff to remove and may require a pair of pliers to ease them out. But no other tools are required and they are simple to fit.

The castors do ‘stick out’ a little, so a skirt at the base of the unit to cover them up would have made them look less out of place. But this is purely a visual gripe and they provide a very useful purpose and should allow you to effortlessly move the dehumidifier in-between rooms without lifting it.

Water Collection

The water collection tank can hold up to 3 litres of water (which is a very good size) and can be accessed by easily sliding it out of the side of the unit for emptying. There is no handle on the tank, which would have made it much easier to carry, but there is a convenient lid on the top so you shouldn’t spill any water as you make your way to the sink to empty it.

On the front of the device you can see a very handy water level window. This will allow you to see at a glance just how full the tank is without needing to pull it out or turn the machine around to check. For those of you who already own a dehumidifier, you will already know just how useful this simple feature can be and it is a bugbear of ours when it is not present, so it is nice to see the Des12 has one.

As with many dehumidifiers, the Des12 also provides a ‘continuous external drainage’ option. Using the supplied two-meter hose you can enable the unit to run without ever needing to empty the tank. The most common use for this is in kitchens or caravans where the unit can be placed securely on a work-surface and allowed to drain into a sink.

Using The Des12 – Controls

If you want an easy to use dehumidifier then the Des12 should certainly be on your shopping list. Its control panel consists of little more than a dial and two feedback lights and is very reminiscent of the Dimplex Forte 10L‘s panel which is just as simple.

The dial has a total of 5 settings ranging from ‘Off’ to ‘Dry’ – with ‘Min’, ‘Med’ and ‘Max’ in-between. To give you a good idea of what each mode does we will quickly run through each one in turn.

1) Dry Mode

The ‘Dry’ mode is really useful and is typically used by most dehumidifier owners to dry washing or to quickly dry out rooms with a lot of excess humidity. When in this setting the Des12 will run continuously regardless of the humidity level reached allowing it to quickly suck moisture out of the environment.

With most dehumidifiers it is recommended not to use the ‘Dry’ setting for everyday use because of the strain it puts on the unit. Even though Delonghi does not provide this warning with the Des12, we recommend following this trend to help extend the life of the device and only use the ‘dry’ mode to deal with excess moisture quickly and then turn the machine down onto a lower setting.

2) Min, Med and Max Settings

Next up are the ‘Min’, ‘Med’ and ‘Max’ settings. They obviously relate to the humidity level the dehumidifier will attempt to reach, but Delonghi does not provide an indication of what Relative Humidity (RH) percentage each setting provides.

It would have been helpful to see this information and based on our experience we would say that ‘Min’ would aim to achieve around 60% RH, ‘Med’ would be around 50% RH and ‘Max’ would be around 40% RH. Of course, we must stress that we are estimating these figures based on common ranges used by most dehumidifiers and this is not based on information supplied by Delonghi.

3) Protecting Standby Mode

When you switch the dehumidifier on don’t be alarmed if it doesn’t immediately spring into action.

In fact, it will take around 3 minutes before it begins dehumidifying. This is not a sign of inefficiency but instead a rather clever mechanism designed to prolong the life of the machine.

Repeatedly turning on and off the unit can place a strain on its compressor (this is the component that helps remove excess moisture from the air). So, a 3-minute standby mode stops the compressor from starting or stopping too often.

4) Indicator Lights

Finally, we reach the indication lights mounted immediately above the dial. The first light indicates if the machine is in standby mode or if it is defrosting and the second light alerts you when the tank is full or inserted incorrectly.

As for the defrost light, this will illuminate if the temperature is too low for the dehumidifier to function correctly and it is a risk (or has begun to) freeze up. This cycles the unit between operating using the fan only and dehumidifying to stop ice from forming inside the machine which would impede its performance.

This is normal with all dehumidifiers of this type where you would ideally want to only use it temperatures of around 5-10°C plus – making it only suitable for use in your home and not in any side buildings or your garage for example.

Biosilver Tech System

Around the back of the Des12 is an easily accessible filter system which features Delonghi’s exclusive BioSilver system. This is a special silver ion coated grid which destroys most bacteria on contact allowing the Des12 to clean the air as it removes moisture.

This is an increasingly popular feature with most dehumidifiers and it is obvious why. The removal of the bacteria from the air will not only help people who suffer from breathing problems but it will also help remove some of the odours associated with damp which are caused by bacteria or spores in the air.


Over the course of one day the Des12 can absorb 12 litres of humidity at 32°C 80% RH. This sounds a lot, and it is, but these figures are quoted for temperature and humidity levels not common in the UK.

Depending upon the damp problem and running time of the unit you would probably only collect 1 tanks worth (3 litres) of water every day or two – and possibly only every week for much milder damp or condensation problems. This is not a problem, but rather a much more realistic expectation of how you can expect this machine to perform.

Plus, it means you won’t need to empty the tank as often – at the figures quoted by Delonghi you would need to empty the tank up to four times a day instead of just once every 2-3 days in UK conditions!

The fan inside a dehumidifier plays a role in how much noise it makes. Most have two fan settings ‘high’ and ‘low’. This gives you an extra burst of cleaning power when you need it (with increased noise) and less power when you don’t. The Des12 only comes with one default speed setting which is a shame because even though this unit is definitely not the noisiest refrigerant model we’ve seen a slightly lower speed could have made it even quieter.

The Des12 can quite comfortably operate in rooms of up to 55m² and would be effective in keeping mild damp and condensation at bay in small homes of up to 2-3 bedrooms or in flats/apartments. Although if you have just one room with moderate to severe damp then this dehumidifier should be able to tackle this too because its efforts would be concentrated in a much smaller space.

What We Think About The Delonghi Des12:

The Delonghi Des12 is a great little machine that can operate in tight spaces and should be adequate for most 2-3 bedroom homes.

It is lacking in features when compared to some of its direct competitors but this only makes it better for anyone who wants a simple to use, but robust machine.