I've been using one for years in a stored car, every winter. It's quite happily extracting a litre every few days and the full turn-off switch works fine. However, don't forget to empty it every so often, as when a big freeze occurs, the ice formed in the catch tank will crack it wide open. Of course, the availability of spares for these is non-existent. As you found, the fan is nothing more than a cheap generic PC component - I replaced the OEM one after a year due to noisy bearings. The replacement, a decent quality Papst, has lasted for years. One thing I found was the unit, more importantly, the power supply brick, wasn't immune to flood damage, and that killed it. It lives on though; now being powered by an ATX PSU, the Peltier modules just chuntering away like they'll never give up. In fact, I was so impressed by how it did its job, when it wasn't being nearly killed by weather and bad luck, I bought another one recently, to go into another car. These things are ok for that size of volume, but for a room, forget it.

Congrats. you became an example against Pontus "The self-filling water bottle"

You are hilarious! "It was certainly worth taking to bits" & "It's brand new but that's never stopped me before"! Thank you for the very educational video & the smiles.😁

Hi man! So basically if I were to have a fan, heat sink, cooling chip and a second heat sink I could build my own dehumidifier?

love your vodcasts Clive they are always so informative. they tell me everything that I need to know about how a device works and therefore how to check it is functioning correctly and repair it if it is not

I had a peltier CPU cooler in my monster rig build, back in 2007. It worked VERY well!

I don't want to break it but when did that stop me before. Lol. I love the fact you are part curious kid, knowledgeable engineer and intelligent comedian all in one.

I bought like 8 of those peltier chips, a while ago. Finally I now have found a use for them

Hi Clive, thanks for this teardown video. I've always wanted a small dehumidifier for a tiny room and had looked into the peltier-based models, but found $35USD+ way too expensive for what essentially is a peltier and a few heatsinks. Now that I know how these things work, I can use a few peltiers I have and some spare heatsinks to recreate this device for only the cost of my time. Thanks again!

Ahh good work, Clive! I've got one of these in an alcove for some defense while a neighbour's overflow pipe was keeping the outside wall wet. Thanks to your efforts here, I now won't have to risk busting it with my curiosity. Big Clive Public Information Service. My next coffee dedicated to you, sir.

I have a slightly larger one of these in a walk in wardrobe with an outside wall. we suffered much condensation mould. since using it we have no mould. they are good for small spaces like wardrobes.

compressor (phase-change) cooling is so more efficient then these peltier fridges and dehumidifiers coming out. I have a compressor mini fridge that draws 45 watts (closer to 500w for a few seconds on startup) and can freeze everything solid, but have a relitive that has a peltier based mini-fridge and is always complaining that the internal temp is around 50 degrees, I put my kill-a-watt on it and it was drawing 200w, not to mention it'll never reach temperature and kick off unlike a compressor version.

Until a few days ago, I haven't heard of the Peltier effect. I got a mini dehumidifier for my bedroom. It does help. Maybe not as well as a dehumidifier that has a compressor.

THANK YOU for this tear down :D. I wanted to see how they build it, now I know :D

You are correct swapping the polarity changes the direction of the heat pump

I had to replace the fan on one of these and couldn't remember which way the it needs to face, thanks Clive!

I wouldn't have thought about a Peltier dehumidifier. I'm so used to the old fashioned refrigerated ones that it never occurred to me that that was an option. Nice find Clive. You dissect some of the neatest little gizmos.

i'm researching in regard to extracting water from air using desiccant surface. if a dehumidifier like this modifies in design it can produce considerable amount of water. thank you for your video very useful

I got one of these its great works really well it lives in my little workshop I need to change its tank about once every 3 days. Yes it does make a slight 'snuffling' noise when its running but I find it nice

If the power supply output allows, you might be able to replace the peltier device with higher wattage one. If you use bigger one you may confront freezing problems instead of condensation, for that reason as you know, you cant go too far on that. You can make your own. Increasing heat sink area may solve freezing problem because it would dissipate the sub freezing cold which I know you know it very well.

thank you for taking the time. was always curious.

Good Video. Interesting to see whats in the dehumidifiers. Have one myself, it extracts 250ML s every day!

I don't feel so bad about my effort to make one now. I re-purposed a mini fridge to act as a dehumidifier and it was able to extract about a teaspoon an hour. The mains power one I bought takes out way more water.

Thanks for the video, I was looking for a mini dehumidifier for 3-D printing, and was looking at them hoping there was a big Clive teardown so I could see what was inside

i like your idea about running off a solar panel. I was thinking the same thing as im aware that these peltier devices are hugely inefficent from an energy perpective. I have a small area at the back of my garage of around 5sq m floor space that is insulated in which i keep my lathe and miller . I think im going to get one to stop flash rusting of the surfaces ( and add around 30watts of heat to the room)

My original intention for this humidifier was to use it for plants that require high moisture levels. After using it in my room, kzfaq.infoUgkxtD9aJ2m6GU-X1IChQxjn9l31K1A7Kpwj however, I think that's where it is going to stay in the fall and winter season at least. The increased humidity in my room made the room warmer and more comfortable. I had first ran the humidifier for 4 hours with the timer setting for it. After the first hour, I checked my room and can feel the difference. When the full 4 hours was up, I checked again and noticed that the humidifier was shut off as it is suppose to. The moisture level never seem to get passed 56/57%. I then let it run until all the water is used up, which it wasn't all used up. There are still some left in the base that you are not suppose to add water to. I filled up the water tank all the way again, being careful when removing it from the base. Some left over water may spill out. After putting it back on and setting the unit to auto, I let it operate. It didn't stop running, rather I don't know if it did at any point since I didn't check it regularly, for 24 hours after which the water in the tank ran out. The moisture reading never passed 56/57%, which may be a good thing for me. Being situated right next to my bed, the noise was not very noticeable with the occasional water gurgle from time to time as the unit ran.

Great review. Thanks Clive. Surprised at how many of your videos I keep finding :-)

This Video is old but You my dude are my saving grace and first address in terms of reverse engineering + DiY Salute

We had a 'mini cooler' at work until some bright spark switched it from cold to hot while still turned on. A loud bang and flash was emitted and muggins here was asked if i could fix it. took it home, the 'hot/cold' switch simply reversed polarity of peltier and had shorted in the middle, melting on/off switch and hot/cold switch into one blob of plastic, and a very charred circuit under them. I took it all apart, sandwiched peltier between original heatsink and a cpu heatsink, fans on both sides, wired it to 12v cpu header on a spare pc power supply rated over 400w. Fans came on and one side gets lovely and cold and the back gets barely warm given its massive heatsink lol. it now sits in a round cliplock container next to my bed waiting for those ugly sweaty long summer nights blowing a chilly cold breeze across my face :D Instant cheap air con, yay !!

Good Video. good pace, good explaination, good teardown.

Hey, hi from AU! Somehow missed this video, and nice to watch the teardown, tell you what these little things are great for - I have one in a small 60x60x50cm(ish) file cabinet/drawer I sealed and insulated and keep printer supplies in - where I am averages 75%rh and goes to 85%-90% quite regularly, this thing keeps 35C 35%rh almost all year round and produces a litre of water every six to eight weeks, excellent for old style lead acid batteries and I also use it to keep solder sponges wet and give the rest away to people that still do ironing... It's been going for almost three years now and reminds me why we like solid state devices...

The module is very cheap, you can get what I think is the exact same unit on ebay for $0.99. This is a 4 amp model, you can get a 15 amp version for $5.00.

My first thoughts were solar-powered water collection as well -did you develop the idea further Clive?

I also have one of these, it runs on only 9V. It has some additional component near the heat sinks, I guess it must be some kind of thermal switch (that either cuts out when the thing heats up too much or maybe when it would be on the verge of freezing). Because the fan is still rated at 12V, I added a ‘turbo’ switch with a booster circuit that brings it at full speed. Even then, performance is still very poor, although it helps a bit to get the moisture out of a poorly ventilated bathroom. But my big compressor-based dehumidifier pulls about 20 times the amount of moisture out of the air per Watt.

There is one thing they forgot in the design..... I have exactly the same dehumidifier running in my shed, but when the temperature in the shed goes below about 8°C the cold side heatsink becomes one big lump of ice ! So I added a 10° clixon to turn it off.... (also added a drain hose so I don't have to empty it manually 😄)

so glad I came across this video I was thinking of buying this very model to keep keep humidity down in my holiday home when I'm not there. However after seeing this I'm a bit shocked at the price of them for what is inside. I could knock a DIY one of these up for next to nothing. (And probably will)

If you reverse the polarity on the peltier junction, It won't just swap the hot and cold sides. It will in fact transport heat in the opposite direction but at a drastically reduced rate. They only really work in one way and therefore they must always be supplied as specified.

I have to say I was very impressed with the one I bought to get all the dampness out of my car. 600ml over the Xmas period in temperatures below freezing. For the price it did a fantastic job, how else to you get the inside of your car dry in winter. Clive, thanks for the breakdown.

Those are great !!! I bought 3 dozen of them. Still haven't found a personal use for them, though. Maybe around my boiler and drained outdoors will keep the rust down. Now to buy large heat sinks. Note to self: when using several in one gadget, it's probably best to leave decent air gaps between them.

Thanks for the video, helped me get going on repairing. I have two of these that stopped working after a year. I’ve replaced the Peltier modules and they’re working well again. I wondered what makes them fail, maybe they were clogged with dust and too hot. Peltier spec. says max 60’C. The Peltier modules on eBay are 40 mm sq, bigger than the originals, but doesn’t seem to matter. Various people have said that the hot heatsink is touching the air on the cold side, I’ve put foam there. Even worse, one of mine had a 50 mm * 2 mm gap allowing hot air into the cold side. Foam in there now. The gap is where the Peltier+heatsinks module does not quite fill the hole in in its plastic housing.

Without a mention of the humidity you exposed it to, and the temperature and square footage of the space, and the exact time allotted for the device to run, there is no way to determine whether the small amount of water you found is reasonable for such a small device or not. When attempting to review a product try to think of all the relevant parameters to pass on as without them you could be misleading people with comments like that. Certainly you know they only function well in ideal conditions: above 50% humidity and about 50F is where they can start to work, but the "bell curve" for performance will be around 80F and 80% humidity so it has plenty to draw from the air. All humidifiers (and air conditioners) depend on the purchaser properly selecting the device for the space and environment. A device like this can take the edge off a small room, like a bathroom, but that's about all. For anything demanding a Peltier unit won't cut it and you need a compressor based unit as mentioned.

Just did some quick maths on this one. The latent heat of evaporation of water is around the 100,000 joules per kilo mark. I think it's actually about 118,000 but 100,000 makes the maths easy. If your kit cools to the tune of 33W then it will take about hour to condense 1kg of water IF it's running at near 100% efficiency. The problem is that the hot bit and the cold bit are too close together so it is working at I would guess 10% efficiency at most.

TES1-12704 TES (Thermo Electric Stack) TES1 (one stage peltier) 127 (number of thermoelectric pairs 04 (max current 4amps) This applies to almost all thermoelectric modules TEC or TES is meant for cooling/ heating And TEG is meant for power generation Number afterwards marks how many stages there are TES1 is most common but you can use TES2 to get slightly higher temperature difference it's basically two modules stacked ontop of each other tho one on colder side is usually 1/4 the power due to efficiency of these modules so you sacrafice efficiency. Numbers after the "-" mark number of couples usually only first three and last two numbers mark the current.

these are quite handy for drying shoes and such. that's what I use them for at least. in the humid summer months they can bring out about a tank worth a day which is not bad for it's size, but yeah if you need a real dehumidifier you should get one.

Thanks a lot! I bought one of these in the begining of the year, but haven't used for some months. When I turned it on, it started a strong noise. By seeing your video I imagined that the problem was in the cooler. So I opened it, cleaned everything, put some new lub in the cooler and ... it worked! :)

Thanks for the video. I have the same model. I now know how to replace the parts if the device breaks down.

Nice job and saved me a bunch of money.

I have the exact one in my towel closet. It was going alright for about a year then he bearings went on the fan. Just replaced it with a Noctua one. Next I was going to see if I could make it battery powered so I can out it in closets without a power point

Now they changed for 9V adapter, possibly lower voltage for more longevity. Just acquired the same, fills the whole bucket in 1.5 days in my 80% room humidity here, despite that it's not able to lower it as unit is too small for room size I suspect.

Why the air is not pulled in from the hot side to the cold, so the temperature difference is greater and the effect would be more efficient? It is logical - just there must be additional air holes behind where the fan is and the fan should pull the air in. Then the air will go hot and then go to the cold side and then exit from the front air holes (not the back ones). And why the cold radiator is smaller then the hot one?

It could work in a small enclosed space to reduce moisture.

I got the larger version of this after a major leak in the house; it took only two days to dry the carpet in the room affected

i'm so glad the production of your videos has improved.

Clive you rock. I want to make one of these and its very helpful to see the inside 👍

Its' interesting that the old big clunky fridge-style dehumidifiers seem to go much further and freeze the water and then cycle to melt that into the bucket rather than just relying on just condensing based on reduced capacity.

For the fun of it, try making a solid state dehumidifier. Take two stainless steel screens and place a hydoscopic salt in between. When there's no water the salt does not conduct, but as the salt absorbes moisture from the air it starts to conduct electricity that eventally breaks the water down to hydrogen and oxygen.

THANKS A LOT FOR YOUR EXPLANATION.. IT WAS HELPFULL TO ME .. IL MAKE ONE OF THIS BY MYSELF!!!

i wish i had 2 of those for a Project

the hot and cold air flows are kept completely separate from each other, not (asking rethorically)

I have often wondered if a Peliter device would be a very good to use to make distilled water. The hot side could be used to evaporate water and the cold side could be used to re-condense it. This should result in a very efficient system. The losses in the Peltier are associated with the devices resistance. By stacking, the necessary temperature difference could be maintained. I have seen such devices used in cabinet rack cooling for telecoms and computer equipment. The advantage of such a system is that the electronics can be sealed from the outside environment, allowing the humidity within the rack to be limited with silica gel packs.

I've been using these for like. 7 years... I leave it in a cupboard I keep my. Guitars.... For where I live, SEA, I can keep humidity at 60 percent while outside hovers around 75 to 85 percent... Not bad... they are robust and still works after 7byears, However the adapter have given up on me twice. I think that's because the temperature of the cabinet sometimes exceeds 32 deg celcius, adapter overheats

This little dehumidifiers works for what is intended to be used, it will not replace a compressor style dehumidifier, but for small spaces like small RV trailers, it will work perfectly. a piece of foam around the peltier will help the cooling and heat effect.

excellent!! saludos desde Perú.

If you ask me, the cooling heatsink doesn't look as big as it could be, and neither is the airflow optimised properly. It looks like a half-baked design, to be honest. You might dramatically improve the performance (proportionally, that is) by slapping on a much bigger cooling heatsink and improving the flow so that the incoming air has to go through the heatsink from top to bottom (or bottom to top), and making sure the outgoing air doesn't interfere with the incoming air.

Great video. Would using a larger Peltier module or larger cold sink make it more effective?

12704, about 4 amper. That easy to over heat. The reason why cheap dehumidifiers using small amper are to get fast sublimation. But it's forcing the so much.

I have had 6 or 7 of these around, bought in batches of 2 or 3, and two a little larger ones. I always knew they won't be the "best thing ever", but it was mainly for space reasons that we got the small peltier ones (e. g. outside wall corner in parent's basement and bathroom, in corners on shelves i my basement), but I did not expect them to perform that bad. After 2 summers of use all the fans are rattling like crazy and all but two of the power supplied died due to failed caps, just what you expected in the description. They were just barely doing their job. Their main effect of getting the air drier is actually just heating it so relative humidity drops. Perltiers are horribly inefficient. If I remember correctly it was something like for every degree the cold side gets colder, the hot side rises by 10. In our basement we now installed some 125mm air ducts from room to room with two fans, so the air is pumped through all rooms in a circle. In one of the rooms there's a compressor dehumidifier (around 300W). It replaced two of the bigger and 4 of the smaller peltier dehumidifiers. This single device is enough to keep all the basement rooms around 65% rH, even in the problematic corners and after days and weeks of 30°C+ weather. So in essence: you're much better off getting an old fridge and leaving it running with the door open than to buy those crappy peltier things.

спасибо.Хоть кто то его разобрал.Так и думал что на элементе пельтье сделан.

lol no isolation between the heatsinks? and joined by a metal screw? and it actually have thermal paste that goes from one side to the other (@9:00). i think, maybe, that's not very optimal.

I guess it could swap polarity every so often to defrost itself? (If used somewhere like a car where temps might get too cold?)

I have one of these, and i am hoping you might be able to tell me why it stopped working. i turned it off for a few days and now when i turn it on both the power and full lights blink and nothing else happens. the water tray is definitely pushed in. thanks

I replaced the Thermal paste with some cooler master thermal one , it did improve the performance of it , would be interesting to monitor both surfaces temperature...

Interesting. I was going to have one of these but seeing this im so glad I didn't.

cool in this ancient video Big Clive reveals that he's just a pair of hands reaching out from the dark shadows !

Try taking apart six of them and assemble their innards in a single peltier monster. Then hook it up to your solar panel and see how much water it drips out ;)

Hello, where I live during summer it gets to around 48°c - 52°c and right now we are experiencing very high humidity which is very bad ☹️ you cannot be outside, we are cloudy right now and I noticed the clouds literally disappear (probably because they are literally mixing with the humidity around the air. Right now is 12am and we have a temp of around 35°c and humidity 43%. 35 people have died in this month because of the extreme heat, do you think or could you do a video about these kind of humidifiers to see if this helps a little to at least bring the humidity down. I wanted to see if these would work to bring the humidity down and save on electricity for the people that are poor and cannot afford to pay high electricity bills

Seems like this would work well for a car or small bathroom to get rid of excess moisture.

You know, I never really thought about using a peltier to _heat_ something. But it would be more efficient than simple resistive heating because you're already getting resistive heat PLUS whatever heat you've got flowing to the cold side of the junction...

Getting a 2nd hand one of these today for 5 quid, be fun to play with if nowt else :)

So there's no air flow from the axial fan directly on to the cold side heat sink? The fan just blows air on to the hot side heat sink?

I think the rubber washers are also to prevent heat conduction through the screws from one heat sink to the other. Having played about with a Peltier plate before the hot side seems to dominate the cold side substantially so I wonder if some kind of insulator other than air would be beneficial between the two heat sinks and perhaps nylon bolts instead of steel screws? Also would the condenser benefit from a bigger surface area and a rougher surface?

Mine has a flashing green light any ideas had it apart power is reaching fan because it's moving slightly but not going around

Now, would running one of these outside on a humid day collect water? Could these be in some way a way to collect water from the air?

Excellent. Thanks much.

Yes! Reposition it.

What if your heat sink was made from copper would it get colder and condensate more water?

Now all we need is a peltier (or should that be Peltier?) based air conditioner for those long hot Summer nights in a tent. Solar charger to keep a battery topped up, and we're in business!

why don't they add more peltier and make it work a little bit more. i love Peltier. i hope it will be the future of a/c

You'd be right to put that more towards the center. I see why it's not working that well too. The condensation heatsink isn't large enough. Neither is the dissipation heatsink. I think you could use the parts to make something far better though. Something with heat pipes would do a right nice job of it for the dissipation side. For the condensation side you want one of those old solid aluminium whoppers for the older AMD chips. Trust me when I say they work quite nicely for that...

I have one of these and found this video while searching to see if there was a filter inside that I could remove and clean to make it work better. Turns out, any dust it sucks in is probably sitting right on the components. After watching this video, I'm curious if it's worth pulling apart to clean, or whether I should just replace it with something more efficient for use in my small bathroom.

I have a similar dehumidifier and it stopped working.It is just in a bigger box with two LEDs for ON and two LEDs for FULL on the front side. Nothing is moving now and all the lights are off.I have opened it to see if I can find what is wrong with it bearing in mind there is no many components inside( fan, peltier module and a few switches ). Maybe this is the best place to ask for advice. Lets me explain what I found and what is puzzling me.The power straight from entering the dehumidifier is around 13.7V. The negative is going to the small (main) circuit board .There is another small board with 4 LEDs( for ON and FULL) with 4 resistors on it. The positive is going to ON/OFF main power switch which is working fine . After that the positive is going to the switch for inserted water collection container( with switch for full tank next to it -the same as on the video).After that is going to the positive side of the same main board.When I measure ( with multimeter) the voltage from negative part of the board to the non inserted water container switch position is 13.6V.Of course, at that point, no power is going to the positive part of the main board and the fan is off( as the peltier module).The unexplained happens when I measure the voltage with water container switch inserted position.Instead of sending the power back to the main board with this switch in inserted position the voltage just disappears.When measured from negative electrode on the negative part of the board it disappears even before the main power switch( ON position).There is just no power at all.Where all the volts are ? I have also checked ( desoldering )the fan and peltier module and one 12V car battery they are working fine.Funny enough when connected directly to the original dehumidifier power source they are not working??? Also there is capacitor between the negative and positive part of the main board rated 25V and 47microF.When insulated it reads 54microF. Is this OK if it reads more than the rated number? Any help will be much appreciated?

Hey Clive. I live in Singapore. Past 4 yrs I went through 4 of these in my wardrobes and kitchen cupboards. They’re on 24/7 and only last about 8-10 months then they just stop working. This time though I didn’t want to chuck it in the bin and get a new one. I want to repair it. I found your video very helpful. Now I know exactly what’s inside but I was actually hoping to hear you tell us what could go wrong with them and how to fix it. If I actually replaced the module, is there a high chance that it will work again? Also, how would I know whether to change the fan too? This DIY enthusiast lady needs some expert help.😁

Old video, I remember watching it when you published it :) quick questions, do you think think would work better if the heatsink had fins like an air conditioning coil?

Love your videos! Can't help but wonder if you could improve performance by adding a second Peltier junction? Is suppose in doing so, however, you might end up icing the cool side and have to add circuitry to shut down the junction for a bit to allow it to melt when it reaches 0°. Then of course there is also double the heat on the hot side. Perhaps a great idea that just wasn't meant to happen.

Hi @bigclivedotcom do you think a better way to extract the humidity would be cycling off the peltier for 30 seconds every 5 minutes or so to allow the freezing water on the cold side to drip? Thanks!

thanks for this videos

Iv got one of these. I put a mini water pump inside the tank and wen it gets full the pump turnes on then pumps out the water into a larger tank

I know this is old. But out of curiosity: Isn't water collection dependent upon your RH? If it is not high, then less water is collected. Higher RH, then more water is collected? So, trying to get a lot of water from a 30 or 40 RH isn't going to produce much? (This is me just thinking out loud, please correct me if I am wrong, which I probably am, as I am ignorant with regards to dehumidifiers.)

hey but how does air from hot part pass to the cold part. the peltier are stuck together. so how does 12v fan passes the air from hot part to cold part

Thermoelectric cooling generation is one of those things that's really cool in theory, and kinda crappy in practice. I tried building a TEC minifridge out of an old cooler and two Peltier units. It did work in the sense that it dropped the temperature of the cooler by a couple of degrees, but it required a ridiculous amount of power to do it. TEC power generation is about as equally worthless, but it is kinda cool, from a science point of view, getting a few volts from just the heat of a tea candle.