PureMate PM420 Portable 20 Litre Dehumidifier Review

PureMate PM420 dehumidifier review ByeMould compressor home house mould mold damp condensation humidityThe PureMate PM420 is ByeMould’s New Favourite Compressor Dehumidifier!

We are quite excited to be reviewing this PureMate PM420 dehumidifier as it’s the first PureMate dehumidifier that we have reviewed. At first glance is looks like a very impressive large compressor type dehumidifier with a 20 litre extraction rate and a massive 5 litre water container!

Of particular note is that the PureMate PM420 rates 4.8/5 on Amazon. Although there are only 17 reviews at time of writing it seems that PureMate is a high quality dehumidifier and air purifier brand so the rating could well be justified.

In fact we like the PureMate PM420 so much that it has become our favourite compressor dehumidifier!

Let’s take a look at the PureMate PM420 by looking at the available features and specifications first.

Features of the PureMate PM420

  • Dual fan speeds and 24 hour timer function.
  • 5 litre removable water tank capacity
  • Portable & easy to move with casters
  • Direct drain option for continuous operation
  • 2 Year manufacturer warranty
  • Power Supply:  AC220-240V 50~60Hz
  • Noise Level on Low/High:  43dB/46dB (+/-2dB)
  • Negative Ion Output:  ≥3 ×106/cm3
  • Coverage Area:  Up to 40 m2 (430 ft2)

Specifications of the PureMate PM420

  • Power Supply:  220-240V 50~60Hz
  • Noise Level on Low/High:  43dB/46dB (+/-2dB)
  • Water Tank Volume:  5 Litre
  • Fan Speeds:  2
  • Timer Selection:  1-24 hours
  • Power Consumption:  370W/1.7A
  • Net Dimensions :  336 x 210 x 547mm (L x W x H)
  • Gross Dimensions :  385 x 260 x 583mm (L x W x H)
  • Net/Gross Weight:  11kg (24.3 lbs.) /12.3Kg(27.2 lbs.)

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Extraction Rate 

Since the pureMate PM420 is a compressor type dehumidifier you will probably find that the actual extraction rate will fall far short of the stated 20 litre extraction rate.

The reason for this is that compressor dehumidifiers operate better in higher temperatures. As such the PureMate PM420 was tested at a temperature of 30°C and a humidity level of 80%. This is actually the standard test climate for compressor dehumidifiers.

A loose rule of thumb for UK dehumidifier purchasers is that if the average temperature in which your dehumidifier is under 20°C then buy a desiccant model. If the average temperature for your dehumidifier is over 20°C then a compressor model could be better.

A compressor dehumidifier that is being used on an unheated landing in the middle of winter will undoubtedly perform very poorly. On the other hand if you use a compressor dehumidifier in a room where the radiators are on a high setting then your extraction rate should be very good.

The PM420 Filter and Water Tank PureMate PM420 dehumidifier water tank pre filter active carbon filter anti bacterial hay fever asthma respiratory problem

The PureMate PM420 boasts a fantastic filter system which is made up of 2 parts.

First the airflow must pass through a washable pre-filter before it comes to an activated carbon filter. An activated carbon filter uses a bed of activated carbon to remove impurities and contaminants via chemical absorption. Therefore VOC’s such as exhaust smoke, cigarette smoke and aerosol sprays etc are also removed from the air.

This double-filter system is very powerful and should be used if you suffer from respiratory.

Water Tank

The 5 litre water tank is without doubt the largest water tank that we have seen on a domestic dehumidifier. Other large dehumidifiers feature a 2 or 3 litre water tank.

There is a grip on the bottom of the tank with which you can pull the tank out of the dehumidifier for emptying collected water and reinserting the tank after it has been emptied.

As with all dehumidifiers the unit will stop operating when the water tank is full. This avoids spillage and other accidents which may occur. Once the tank has been emptied and reinserted correctly the dehumidifier will continue to work.

There is a plastic window on the water tank which allows you to see the water level inside the tank without pulling the tank out. This is a smart move by PureMate as you can imagine that a full 5 litre water tank will be quite heavy. By emptying the tank before it is full you will not only avoid possible accidents but you will not have to struggle to take the tank to the sink when emptying it.

Continuous Drainage Facility

The PureMate PM420 dehumidifier also features a continuous drainage option. By simply connecting a hose to the rear of the unit you can leave the dehumidifier run continuously once placed above an appropriate drainage point.

With the continuous drainage option you can use the PM420 in less visited places such as garages, sheds, caravans and boats etc.

Note: The PM 420 does not come with a supplied hose for continuous drainage due to the large water tank. Should you want to use a hose you can buy one elsewhere or you could try a length of UK garden hose.

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PureMate PM420 dehumidifier byemould control panel laundry mode ioniser timer fan speed settingsControl Panel

The black soft touch control panel looks great on the white PM420 and its simple to understand and use. Having said that we will quickly run through the main points of the control panel for easy reference.

LED Display Panel: We are delighted to see that the PureMate PM420 features a LED display on the control panel. When operating a dehumidifier we like to see what the current temperature and humidity levels are. The display shows both temperature and humidity.

Humidity Setting: This allows you to select your target humidity level and ranges between 40%-70% relative humidity. Most often you would probably select the 50% option.

Laundry Mode: This setting places the dehumidifier on maximum power and is ideal for drying washing indoors. The PM420 will run continuously when using laundry mode.

Fan Speed: You can choose between a low fan speed or a high fan speed.

Power Button: Simply turns the unit ‘on’ or ‘off’.

Timer: The build-in timer is a great feature. Amazingly you can set the timer from just 1 hour up to a massive 24 hours.

Ioniser: The ioniser compliments the pre-filter and active carbon filter perfectly. Those with respiratory problems such as hay fever, asthma etc find breathing difficult when there are too many positive ions into the air. An ioniser places negative ions into the air which pull down positive ions. This results in there being less positive ions in the air and in turn makes breathing easier.

The active carbon filter is one of the best filters for taking impurities out of the air so the resulting air after using the PureMate PM420 is very clean, very healthy and promotes great relaxation.

PM420 Humidty Light PureMate PM420 dehumidifier compressor mould mold damp humidity condensation house home boat caravan office hairdresser museum

A feature on the Puremate PM420 that we really like is a light on the front panel of the dehumidifier. This light changes colour as the humidity changes therefore you can easily see what the current humidity level is even when you are on the otherside of the room. Very nice!


According to PureMate the PM420 has a running volume of between 43 db(A) and 46 db(A). For a compressor dehumidifier of this size this volume level is actually quite good.

Of course a dehumidifier’s volume level is very subjective with some people saying they can sleep with the unit on while others say the can’t. In the case of the PureMate PM420 you should not go for the quietest dehumidifier rather look at the whole package…you’ll be well impressed.

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Power Usage

According to PureMate the maximum power consumption is a very low 370 watts. This is pretty incredible for a compressor dehumidifier that is said to pull 20 litres of moisture per day.

Many other large dehumidifiers would easily use 600 watts of power and more when placed in the highest settings.

The PM420 is Suitable For

Being a very large compressor dehumidifier the PureMate PM420 is suitable for large 4/5 bedroom homes, cottages and smaller offices etc.

Stated coverage is around 40m² or 430ft².

PureMate PM420 dehumidifier fight kill mould bacteria voc fungi fungus get rid of damp mould mold condensationWarranty

PureMate provide a 2 year warranty on all of their products.

Box Contains

1 x PureMate 20 Litre Dehumidifier PM 420
1 x User Manual

Final Thoughts

Wow! We are seriously impressed with the PureMate PM420 as it has all the bells and whistles that you would expect to see on a dehumidifier.

The filter system is superb especially when combined with the ioniser. We love the LED display panel and the unit looks good although this is largely down to personal taste.

There are 14 reviews of the PureMate PM420 on the PureMate website and each review rates 5/5 for price, quality and overall. We can easily see why this is especially if you can purchase the PM420 at a discounted price. You can check the latest price on Amazon here.


As mentioned in the above review the PureMate pM420 rates 4.8/5 on Amazon and 5/5 for all the catagories on the PureMate website. these are stellar numbers but it is easy to see why the unit has achieved these ratings. Here are what PM420 purchasers are saying on the PureMate website:

  • ” In short if you live in house full of lots of people pumping water into the air get one of these”
  • “Large, well designed water collection bucket. Good price. very Happy”
  • “suffering from mold everywhere. This seems to have fixed the problem”
  • “Nice appliance. Quiet and efficient”
  • “does a great job pulling excess water. No more nasty mouldy”
  • “Although it looks expensive but worth every penny”
  • “not even misting on the windows in the morning”

Check THe Latest PM420 Price on Amazon Here


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