Alen MDF3-30 Dehumidifier Review


The Alen MDF3-30 Dehumidifier is a 30 pints per day model designed for smaller areas. This is an energy efficient machine with Energy Star® qualification. While this appliance is most likely to appeal to someone looking for a unit for a room inside the house the MDF3-30 is suitable for use in a small basement, although for most basements a model with a greater moisture extraction capacity will be needed.

Alen MDF3-30 Dehumidifier

Although it is the smallest in the range the Alen MDF3-30 Dehumidifier has all the features of the larger models and is as flexible and controllable as its "big brothers". An adjustable humidistat gives you control over the level of humidity you want the appliance to maintain and electronic controls make setting the humidistat and other functions easy and intuitive.

Continuous drainage is an option if you don't want to be emptying a bucket once or twice a day and you have two fan speeds to choose from. While not a low temperature appliance the MDF3-30 will not come to any harm in temperatures as low as 41°F due to its auto-defrost feature. The unit is easily portable and has a washable air filter.

Few user reviews or ratings are available for the Alen MDF3-30 Dehumidifier. This is not surprising as Alen does not have a large share of the market for these appliances and in general small units are less popular than larger ones with customers in the USA. Those that have submitted user reviews are well pleased with their purchase and have reported good results in smaller areas and in other applications, such as a recreational vehicle (RV).

We have no problem in recommending this model for its technical merits. It is a little more expensive than some other dehumidifiers of the same size and only time will tell if it repays the extra cost with greater reliability.


The Alen MDF3-30 Dehumidifier is a very compact appliance with a "footprint" only 13" by 10" and is just 20" tall. This should make it easier to locate in a home where floor space is a little limited. It is also portable having caster wheels for movement across smooth floors and carry handles on each side just below the top of the machine. It weighs 46lb which is on the heavy side for a model in this class but this reflects the solid build quality of the appliance and may be a disadvantage worth accepting.

The Alen MDF3-30 Dehumidifier has two fan speeds which is why its noise level is expressed as a range between 49 and 52 dB. The main way a given dehumidifier increases its "work-rate" is to increase the speed at which air flows in and out of the machine. The fan is the primary source of noise and is often described as resembling that made by an air circulating fan of the type frequently found in our homes.

This appliance is relatively quiet and the difference in noise level is less than the 3 dB difference between the higher and lower speeds might suggest. The dB scale used to express the loudness of any sound is not a linear scale. 52 dB is, therefore not simply 3/49 greater than 49dB. The scale is a logarithmic one and progresses in a similar way to the Richter Scale used to express the power of an earthquake. A difference of 3dB is barely perceptible to the human ear whereas a difference of 10dB would be perceived as twice as loud.

The Alen MDF3-30 Dehumidifier is equipped with an adjustable humidistat which allows the required level of relative humidity to be pre-set anywhere in a range from 35% to 80%. Once set the compressor only operates when it needs to, cycling on when the RH rises above the pre-set level and off when it has fallen back to the set percentage.

The fan may continue to operate even when the compressor has switched off. This is because the air flow is necessary in order for the humidistat to monitor the relative humidity in the room. The fan uses a very small amount of energy and it is the compressor which consumes the bulk of the power. The humidistat therefore avoids wasteful use of electricity and also prevents the air becoming too dry which can be uncomfortable for most people.

The MDF3-30 includes an auto-defrost feature which allows it to operate safely at temperatures as low as 41°F. Ice will form on the condenser coil at temperatures as high as 65°F and if the ice remains it will damage the appliance. Auto-defrost suspends the water extraction process until the ice melts, protecting the appliance.

The ice is melted by the flow of ambient air as the fan keeps running. Clearly, the cooler that air the more time the unit will be in defrost mode and the less moisture it will extract from the air. Because of this a portable model is not an ideal choice for use in an area which is cooler than 60°F for long periods.

The MDF3-30 is designed to allow continuous drainage as an alternative to emptying the bucket. A small bore hose will feed the water from the unit to any nearby, floor level outlet. As this is gravity fed it will help if the unit is raised a foot or two above floor level.

The appliance is programmed and controlled using easy to use electronic controls which have been praised by consumers. In the event of a power outage the unit will be switched back on by the auto-restart function at the previously programmed settings. There will be a slight delay before this happens, to protect the compressor.

The washable air filter should be removed and cleaned about every two weeks. It is not necessary to wash it on every occasion as dusting with a soft brush will usually be sufficent. Attention to this minimal maintenance task will extend the life of the appliance and maintain its operating efficiency.


Brand Alen
Model Alen MDF3-30 Dehumidifier
Application(s) Domestic
Suitable for Medium sized areas
Portable Yes
Carrying handles Yes, (2) sides
Wheels/castors Yes
Weight (lbs) 46
Dimensions, inches (WxDxH) 13 x 10 x 20
Dehumidification process Refrigerant
Water extraction 30 pints per 24 hrs
Water container capacity (pints) 10.7
Container full indicator Yes
Auto-power cut off when full Yes
Continuous drainage option Yes (to nearby drain/sump)
Minimum operating temperature 41°F
Anti-frost Yes
Air Flow Volume (CFM) TBA
Electronic controls Yes
Adjustable humidistat Yes
Variable fan speed settings Yes (2)
Noise level 49-52dB
Power input 490W/115v

Consumer Reactions

While user reviews of this model are relatively few those that have been submitted are favourable and give the Alen MDF3-30 high ratings. It is reported to be effective, eay to use and quiet. The weight of the unit is felt to be a little too great. There have been no complaints about reliability.

Our Recommendation

We can confidently recommend the Alen MDF3-30 Dehumidifier as an effective room dehumidifier for smaller areas. We cannot say for certain that its long term reliability will justify its higher price but have no reason so far to doubt this.

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