Thus far, we’ve tested eight different thermo-electric dehumidifiers for review. We’ve also reviewed six additional units without testing them. We didn’t test these six additional dehumidifiers to avoid redundancy in our experiments – these six other units had very similar (in many cases the exact same) manufacturer specifications as those units we did test. Below we’ve ranked the 14 total thermo-electric dehumidifiers we reviewed within three different categories. Clicking on the model name for each unit will take you to our editorial review for each particular model. Below these rankings you’ll find a quick explanation of how thermo-electric dehumidifiers work. We round out our buyer’s guide by listing the advantages and disadvantages thermo-electric dehumidifiers have over compressor based and desiccant dehumidifiers.
MINI (4 to 9 ounces of moisture removal per day)
#1 Ivation IVADM10 (highest tested moisture removal rate in class)
#2 Gurin DHMD-210 (quietest in class and overall)
#3 Eva-Dry EDV-1100 (best consumer reviews and warranty in class)
#4 Ivation IVAGDM20
#5 Ivation IVADM15
MID-SIZE (11 to 14 ounces of moisture removal per day)
#1 Ivation ERSDM18
#2 SPT SD-350
#3 Ivation IVADM20
#4 SPT SD-350TI
#5 Perfect Home EWDH4
LARGE (20+ ounces of moisture removal per day)
#1a Ivation IVADM35 (tied for highest tested moisture removal rate in class)
#1b Ivation IVADM45 (tied for highest tested moisture removal rate in class)
#2 Eva-Dry EDV-2200 (best consumer reviews and warranty in class)
#3 Gurin DHMD-310
Note: We’ve classified each of the dehumidifiers above according to how much moisture they remove per 24 hours – “mini” units remove less moisture per 24 hours than “mid-size” units which remove less moisture per 24 hours than “large” units. Do note, however, that despite their being classified under the “mid-size” category above, the SPT SD-350, SPT SD-350TI, and Perfect Home EWDH4 were all classified as “large sized” units during our moisture removal testing. The test parameters used in testing these three “mid-size” units were the same test parameters used in testing the “large sized” Ivation IVADM35 and IVADM45. Different test parameters were used in testing the three “mini” thermo-electric units we’ve listed above. For more information on what test parameters were used according to which size dehumidifier we were testing, see the respective section on moisture removal rate in any of the specific model reviews we’ve linked to above.
How A Thermo-Electric Dehumidifier Works
Thermo-electric dehumidifiers (sometimes called Peltier or Peltier effect dehumidifiers) use the thermoelectric effect (more specifically the Peltier effect) to convert electricity into a temperature difference across a Peltier module. This created temperature difference is what facilitates dehumidification. Before we look at the parts and processes involved in the operation of thermo-electric dehumidifiers, let’s first discuss the science behind how they work. That science is the thermoelectric effect.
The Thermoelectric Effect
The thermoelectric effect is simply a physical phenomenon that relates electricity to temperature change. It states that temperature differences can be converted into electricity and conversely, that electricity can be converted into temperature differences. In the 1800s a physicist by the name of Thomas Johann Seebeck observed temperature differences across two different metals creating electricity – this phenomenon was aptly named the Seebeck effect.
Also in the 1800s, another physicist named Jean Charles Athanase Peltier observed the opposite phenomenon – he observed that when he applied a voltage across two different metals it created a temperature difference – this phenomenon is known today as the Peltier effect.
Note that the term thermoelectric effect encompasses both of these phenomena – the Seebeck effect and the Peltier effect. However, when it comes to thermo-electric dehumidifiers, only the Peltier effect is involved. Electricity is run through the Peltier module inside of the dehumidifier. This electricity creates a temperature difference within the module. One side of the module heats up, while the other side of the module cools down. This temperature difference facilitates dehumidification. We explain how below.
Thermo-Electric Dehumidifier Parts
A thermo-electric dehumidifier is made using very few parts. It consists of
1. The Peltier module
2. Two heat sinks – a smaller cold side heat sink and a larger (about twice as large as the cold side) hot side heat sink
3. A fan – on most thermo-electric dehumidifiers under $100 this is nothing more than a small 12V computer style fan
4. Various switches and buttons
The Peltier module is sandwiched between the two heat sinks. As we discussed above, one side of the Peltier module gets cold and the other side gets hot when electricity is run through it. The cold side of the module is in direct contact with one heat sink. The hot side of the module is in direct contact with the other heat sink. The cold side heat sink is on the side of the dehumidifier where warm humid air enters – the front of the dehumidifier. The hot side heat sink is on the back side of the dehumidifier. Behind the hot side heat sink is the small brushless fan that pulls air through the whole assembly.
So we have, in order from the front of the dehumidifier where air enters to the back of the dehumidifier where air exhausts through the top:
- The cold side heat sink
- The Peltier module
- The hot side heat sink
- The fan
It’s important to realize that the fan pulls the air around this whole assembly of parts toward the back of the dehumidifier. There the air exhausts through the top of the dehumidifier.
The Process
Warm humid air enters the dehumidifier through the front grille. It’s being pulled into the dehumidifier by the fan at the back of the dehumidifier. This warm humid air first comes into contact with the front of the cold side heat sink. Here is where dehumidification occurs. Just like warm air condenses onto the cold evaporator coils of a compressor based dehumidifier, the warm air that enters the thermo-electric dehumidifier condenses onto its cold side heat sink. The cold side heat sink has a smooth finish with a angled finned design to allow for the condensate to easily drip down into the condensate collection reservoir below it.
Keep in mind that the same air is still being pulled into the back of the dehumidifier. The air essentially travels around this front cold side heat sink and the whole Peltier module/ heat sink assembly to the back of the dehumidifier. Here the air is pulled past the hot side heat sink. The air exhausts out of the dehumidifier as warmer (because of the hot side heat sink) dryer (because of the cold side heat sink) air.
Now that you know how thermo-electric dehumidifiers work it’s time to look at how they compare to their compressor based and desiccant counterparts.
Thermo-Electric Dehumidifier Advantages and Disadvantages
Below we list both the advantages and disadvantages that thermo-electric dehumidifiers have over compressor based and desiccant dehumidifiers.
Advantages
I. Quiet Operation
The first real advantage that thermo-electric dehumidifiers have over compressor based or desiccant dehumidifiers is in the fact that they produce very little noise, even less than desiccant dehumidifiers. The only part of a thermo-electric dehumidifier that produces noise is its fan. As we described above, on most units this is nothing more than a small brushless fan.
Compressor based dehumidifiers have a compressor and much larger fans which produce much more noise. Desiccant units have large blowers that produce more noise than the small 12V fans found on thermo-electric dehumidifiers.
II. Reliability
Reliability is both an advantage and a disadvantage for thermo-electric dehumidifiers – in other words, thermo-electric dehumidifiers are both reliable and unreliable at the same time. In terms of design, thermo-electric units are mostly reliable. First, the dehumidifier overall has a very basic design with very few parts that can break. Secondly, the parts that do make up the dehumidifier are very simply designed in and of themselves. The Peltier module itself has a very simple design with no moving parts. Theoretically, it can easily last upwards of 10, 20, even 30 years. The heat sinks are metal parts that don’t wear down. The various switches and buttons on the dehumidifier have a basic design. There’s no complex control panel, no hydrostat (on most units), and no compressor – a thermo-electric dehumidifier has a very basic design.
In terms of the quality of the parts used in their construction, thermo-electric dehumidifiers are very much unreliable. Most of these dehumidifiers are very inexpensive. This is because very inexpensive parts are used in their construction. Theoretically, a Peltier module can last several decades. However, the Peltier modules used in these dehumidifiers are the cheapest most low quality modules on the market. They still may last for several years, but certainly not for the decades higher quality modules can last for. The heat sinks are simply metal parts – they can’t break and don’t affect the dehumidifier’s reliability. The 12V brushless fan that pulls air through the dehumidifier is perhaps the weakest part of the system. These fans often need replacement. Fortunately, they are for the most part generic 12V computer style fans – replacement fans are cheap and easy to find.
The bottom line is that thermo-electric dehumidifiers are, at least for the most part, cheaply made in China. They’re constructed using only the cheapest lowest quality parts. This fact is, however, offset by the design of the parts used in their construction. None of the parts have a highly complex design that requires that high quality components be used in their construction for them to function properly and for a reasonable amount of time. Keep in mind also that the low cost of parts translates into a low final purchase price for you, the consumer. Most thermo-electric dehumidifiers retail for well below $100, with many being as inexpensive as $40 or $50.
Consumer Reviews and Thermo-Electric Dehumidifier Reliability
In discussing the reliability of thermo-electric dehumidifiers we need to make an important distinction in how we assess the reliability and durability of this type of dehumidifier compared to how we assess the reliability and durability of a compressor based dehumidifier. In all of our compressor based dehumidifier reviews we use consumer feedback as a tool to aid us in determining how reliable any particular dehumidifier is. We only test the dehumidifier for a period of a few weeks which isn’t enough time to determine its reliability. We look to consumer reviews because consumers for the most part leave reviews after several weeks, months, even years of use. This is a much better time frame in which to determine any particular dehumidifier’s reliability. We find that units with a high number of negative consumer reviews normally have reliability issues. This is because “reliability issues” is the number one reason most consumers leave negative reviews for compressor based dehumidifiers.
When it comes to assessing the reliability and durability of thermo-electric dehumidifiers we cannot use consumer reviews to assess dehumidifier reliability in the same way. This is because a high percentage of negative consumer reviews left for thermo-electric dehumidifiers have absolutely nothing to do with their reliability. Instead, the focus of most negative reviews is on the fact that the dehumidifier doesn’t meet the consumer’s expectations in terms of moisture removal rate and capacity.
Many consumers buy a thermo-electric dehumidifier expecting it to perform just as well as a compressor based dehumidifier. As you’ll see below, this simply isn’t the case. Thermo-electric dehumidifiers have their own niche to fill – they do not serve as a replacement for more expensive compressor based dehumidifiers. Still, consumers have the expectation that these units will perform comparably, and thus, when they don’t they’re extremely disappointed. This disappointment in many cases turns into a negative review. Thus, we cannot use the negative review rate (percentage of 1 and 2 star reviews) of thermo-electric dehumidifiers in assessing any particular model’s reliability.
Disadvantages
When it comes to disadvantages, thermo-electric dehumidifiers have several. We list them below.
I. Moisture Removal Rate
Most thermo-electric units are rated to remove between 8 and 20 ounces (0.5 to 1.25 pints) of moisture per day. Compare this moisture removal rate to 15 to 20 pints per day for the average residential desiccant dehumidifier and 50 pints per day for the most popular compressor based dehumidifiers. A thermo-electric dehumidifier is simply not an option if you need humidity removed at a high rate. Only use one of these dehumidifiers if you have the patience to let it dehumidify over very long periods of time.
II. Limited Capacity
Because they can only remove about one half to one and a half pints of moisture per day, thermo-electric dehumidifiers can only be used in very small spaces. They will make no impact on the humidity of a large humid room (and by “large room” we include even an average sized bedroom). These dehumidifiers are only good for small bathrooms, small closets, small laundry rooms, etc.
We want to note here a deceptive business practice used by many thermo-electric dehumidifier manufacturers. It’s common practice for builders, realtors, etc. to refer to the square footage of a room in describing its size. Thus, most large capacity compressor based dehumidifier manufacturers state the square footage of the space that any particular dehumidifier model is capable of dehumidifying in order to give potential customers a better idea as to whether the dehumidifier they’re planning on buying will fit their requirements. The top rated Midea Cube, for example, can dehumidify a space up to 2500 square feet.
Because thermo-electric dehumidifiers can only dehumidify a very small space, many manufacturers state the cubic feet their dehumidifiers can dehumidify. Let’s do a quick bit of math to show you why this is deceptive.
To find the square footage of a room multiply its length by its width. Thus, a 10 ft long and 10 ft wide room is 100 square ft. To find the volume of the same room multiply its length by its width and multiply that number by its height. Thus, if that same room has 10 ft high ceilings, multiply 100 by 10 – the room has a volume of 1000 cubic ft.
1000 sounds a lot larger than 100 but remember, 1000 is the number of cubic feet that make up the volume of the room. 100 is the number of square feet that make up the size of the room. Thermo-electric dehumidifier manufacturers use the larger, more impressive number because if they used the smaller industry standard number to describe room size, it would pale in comparison to the room size that a compressor based dehumidifier can dehumidify.
The Ivation IVAGDM20, for example, is said to “be suited for spaces up to 1,100 cubic feet”. In terms of square footage, if the space is 10 ft high, it is only 110 square ft. Again, the top rated Midea Cube is suited for spaces up to 2500 sq ft – it can dehumidify a space approximately 25 times as large as the space the IVAGDM20 can dehumidify.
III. Value
The Ivation IVAGDM20 is a good example of your average thermo-electric dehumidifier and the Midea Cube is a good example of your average compressor based dehumidifier. The Ivation retails for about $50, can dehumidify a 110 sq ft space, and removes 0.5 pints of moisture per day. The Midea retails for approximately $250 but can dehumidify a 2500 sq ft space and removes 50 pints of moisture per day.
Thus, the Midea is 5 times as expensive as the Ivation but can dehumidify a space 25 times as large and can remove 140 times as much moisture per day. This is only one example and one comparison of two popular dehumidifiers of each type – if you compare other thermo-electric dehumidifiers to other compressor based dehumidifiers you’ll see similar ratios. It should, however, be clear even from this one example that compressor based dehumidifiers are without question a much better value compared to thermo-electric dehumidifiers.
That being said, you may not have $200 to $300 to spend on a compressor based dehumidifier. You may also not have that large of a room to dehumidify and the room you need to dehumidify may not be severely humid. If all three of these things are true a thermo-electric dehumidifier can still be a viable option – it will still dehumidify, just not as well as a more expensive compressor based unit. The bottom line is that while compressor based dehumidifiers are a far better value, they can be overkill for certain situations. Again, if the space you need to dehumidify is small and only mildly humid a thermo-electric dehumidifier can work and work just as well. In this situation our recommendation would in fact be to simply buy a thermo-electric dehumidifier. There’s no need to buy a much more expensive compressor based unit if you don’t need it.
Have a question or comment? Let us know below.
I was wondering what the power consumption difference is between the two types?
I live in Hawaii and dont have central air. I have been using these thermoelectric units in closets and closed rooms to avoid mold blooms which can destroy a lot and be a health hazard.
Wow–so informative! Wish I would have found this post before buying the $45 “semi-conductor” dehumidifier for our 80 sf bathroom in NoCal to help bring down the RH in the adjacent bedroom. Your post helps explain why I’m disappointed with it–just didn’t work well. Was hoping a small counter-top unit would work in this little space. Sounds like I may have to ante up for a bigger/louder one…
Low capacity can dry the room eventually, to the level that you need IF YOU DON’T OPEN THE DOOR to the room. As soon as you open the sealed room, humid air gets in, and you have to start the long journey to pull the moisture out of the air. Just like a small engine car will get you to 100MPH, eventually. If you have a room that is sealed most of the time, a small dehumidifier will be fine. A small room, that has it door open and closed many times a day, like an RV, it will take too long for a low capacity unit to keep up.
0.5 pint per day per 110 sq ft = 0.004546 pint per day per sq ft
50 pints per day per 2500 sq ft = 0.02000 pint per day per sq ft
0.0200/0.004546 = 4.4X better performance
$250/$50 = 5X more expensive
SO, base on that, value is about the same.
On YouTube, you will find no shortage of complaints of high failure rates of compressor based dehumidifiers. My first compressor based unit, Kenmore made in US, purchased in 1980 lasted 20 years. Since then I had 2 more, made in China, each lasted about 2 years. I cannot find good quality compressor based units even of I am willing to pay higher price. Higher price now gets me higher performance, not necessary reliability. Commercial grade units are too expensive and more performance (pints per day) than what I need. One Youtuber’s study points to the lack of quality welding and soldering of copper tubes that transfers the freons. Low cost components, like thin wall copper tubing will not withstand corrosion for long period of time, leading to an earlier freon leak. Many other low quality components such as seals, condensers, etc. also contribute to the lack of longevity of compressor based units. So, my take is that less components, less to go wrong. Fan is easily replaced. controller circuit board vs. circuit board is a wash. heat sinks are non moving and not as much exposed to corrosion. Peltier elements are the highest risk. If they fail, the unit is toast. Depending on how they stack the quantity of the Peltier elements, i.e. welded, soldered, thermo glued, mechanical compression (screwed together by brackets), you may be able to salvage the remaining good ones and use the failed unit as a parts donor for other units that you may have.
Having fewer parts in Peltier based units equates to reliability.
Really, really fantastic and informative. Helps me decide what I need. Thanks!
really learned a lot. Thank you. So the peltier thing is too little power. can I use it for a one room (exple bedroom)?
Nasser, that’s what I do and it works great for keeping humidity lower over time. That’s the key with these things, they just lower humidity over time, not quickly.
Thanks for your very informative review. I would like to know how the two types of dehumidifiers compare in terms of energy consumption. So something like wattage per moisture removal rate? Since the cost of electricity is ever increasing this is becoming more important these days
My posted value discussion did not include power consumption. Different region have different electric power cost. In my area, non-peak time power cost is about 1/5 of peak time. This will work out OK if your goal is to sleep in a dryer bedroom. Turn on the unit, compressor or Peltier base, at the start of the non-peak time, around 9-10PM. By the time you go into your bedroom to sleep, it will be dry-ish. You can shut it off couple of hours before you wake up. Peak time starts around 6-7AM.
Or even watts/hour
Moisture removal is highly dependent on humidity level. But these units probably use a pretty consistent amount of energy regardless.
Excellent explanation
So basically, there are more cons that pros?
I’ve learn some good stuff here. Certainly worth bookmarking for revisiting. I surprise how a lot effort you set to create such a excellent informative web site.
Hi there!
Love the site, it’s been so helpful in researching the right dehumidifier for my home in terms of quality but I do have a question about cold weather vs warm weather dehumidifying. We have a small laundry area that would greatly benefit from something like the IVADM10, but I’m not sure if it’s suited for the NZ climate if it’s marketed for something like Florida.
I live in south New Zealand now, next to the ocean in a town that has chilly and damp winters. (Dunedin NZ, Edinburgh’s sister city climate wise)
Indoor mold growth is a huge problem here.
Are most of the dehumidifiers recommended on the site actually suited for dehumidifying when the ambient temp is 41-55°F in the months they’re needed? Should I be looking at a particular style over another?
Compressor based dehumidifiers will work at lower temperatures and are still more effective than other types of dehumidifiers at the temperatures you specified. We cover this topic in more detail in our guide on basement dehumidifiers.
One nice thing about compressor based in cold damp weather is they heat and dry the air. I use both units (in Hawaii) but only use the the compressor based unit on those few cool super moist days we get in “winter” most of the time I use the small thermoelectric units to keep closets and closed rooms mold free…
I’m looking to build a 1-5 L drybox for my 3D printer filament; how do peltier devices perform at really low humidity values? I want to extract as much water as I can out of the plastic filament I’m hoping to print with. The peltier devices seem really convenient as the waste heat could be used to heat the plastic filament to keep it above room temperature to help drive out as much water as possible.
Should I consider a peltier, or stick with desiccant?
Thanks for your time!
The key element in drying 3d printer filaments is to raise the ambient temperature inside the drybox enough to warm the filament to a temperature where it would readily give off it’s moisture content to the relatively “dry” air around it. If the peltier module can warm the cool, dried air coming from the cold side to about 40°C and maintain that temp within the drybox then I guess it should work.
I have a 450 sq ft camper. Im looking for either one compressor unit or 2 Thermo electric units. Which one would you recommend for being in different environments and the least amount of noise. Also have to consider the separate areas of the camper as far as rooms
We recommend a compressor based unit. Thermo-electric units simply don’t pack enough of a punch even for a relatively small 450 sq. ft. environment.
Don’t worry about putting the unit on one end of the camper. The air in the whole space will go to equilibrium as humidity is reduced – i.e. the dehumidifier will be able to lower humidity in the whole space, regardless of whether it’s placed in a central location or not.
I know admin dis agrees but I would run the thermoelectric units and if you plug into shore power when its parked, I would leave these units going 24/7. Protect your investment, it’s like having a giant bucket of desiccant in there. Only drawback is you have to empty the reservoir. But larger units come with a hose…
Do the Thermo electric dehumidifiers suffer from ice build up and what are the potential causes?
I am SO glad I found your site. I’ve been looking at small bedroom sized dehumidifiers and was just about to pull the trigger in a highly rated Peltier Technology unit, then read your explanation of how they work and why they won’t work in larger areas, so I’ve scrapped that idea. Now to find a small unit that will not deafen me at night but will still suck water out of the air…… do you have any recommendations for a small, quiet unit?
Thanks again for saving me from making a big mistake!
Kim
This is our recommendation for a small quiet compressor based unit.
I read on your blog that the current (2023) equivalent is the 22 pint. We have a 80 sq foot (or 640 cu ft) bathroom that is adjacent to our bedroom (approx. 225 sq ft) where the windows in winter drip with water in the mornings. Would you still recommend this 22 pint size or larger compressor?
I have noticed that at least one manufacturer (Vremi) claims that their large-capacity units (30 and 70 pint/day) operate using Peltier cooling. I have been trying to get clarity on whether this is in fact correct, but nobody (in the massive Amazon community, or so far from Vremi customer support) has been able to give me a straight answer so far.
Is this credible now (6/19)?
Vremi large capacity units are compressor based. It’s physically impossible for them to remove 30+ pints of moisture per day otherwise.
you say most use a PC case fan, would it be possible to just replace the fan with an aftermarket PC fan that is designed to run quieter than the junk that is most likely installed my the manufacturer of the dehumidifier?
are the mounts and power supply imputs the same?
Thank- you for your information. I have spent 3 days wondering why these units look- alike- are priced-alike and are so much cheaper than many other “similar capacity” dehumidifiers.
I have all of my room measurements: (TOTAL 820 square feet); however, could not understand large price differences in the plethora of humidifiers out there. Additionally, I live in an apt. in which I do not need a very large unit, so I focused on “smaller less-expensive units that I believed would do the job.” —-perhaps 2 units.
I now will choose a compressor unit: would it be wise to buy ONE unit, position it in the living room and assume it will dehumidify my bedroom at the other end of the apt, (with no walls, turns or obstructions.? Bedroom noise level is a concern—and I have thought about purchasing 2 smaller units with hope that the compressor noise level might be acceptable if unit were placed in living room as the humidification might be adequate to reach my bedroom?
Yes, the dehumidifier should work very well for the application you specified if you position it the way you specified as long as its a high enough capacity unit. We recommend a 70 pint unit for the square footage you specified.
Could it work in a 25 square metre room if you left it running for a longer period?
Also the room is only mildly humid throughout the year. Thanks
Yes, a thermo-electric unit could work.
3 years ago, I purchased 2 of them.
They brought my relative humidity of my house down by 2%.
It still was up to 62% humid during monsoon season.
So they were totally useless for the home.
Not only that, but their fans are not whisper quiet. They use straight bladed fans, and a very inefficient heat/cool sink design.
The Eva and a whole range of other chinese peltier dehumidifier manufacturers, are all the same. Yet the Eva makes it heads out number one in the list, while the others are in the middle?
And for 3 years, I’ve been waiting for someone to make something like this for the car.
Those peltier elements are working on 9V, but would work slightly better at 12V.
Yet 12V will roast some of the onboard electronics.
Don’t bother with them, until they make a more portable and efficient 12v version.
Running a/C in your car(if you have it) will help dehumidify your car. In fact in many vehicles the a/C compressor runs in defrost mode as well.
I’m also interested in a car version or a built in version to keep in car humidity below a set-point 24/7. Esp EVs that use a lot of energy to run ac.