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how to make a diy dehumidifier ? Answered

How can we make a dehumidifier, cheap. easy ? Thanks to you guys and girls ;-)


if you need to dehumidify air in a closed space - maybe its better to just take fresh air from outside ? all the fan and pipes solutions work better when you enhance the surface area of the pipes. for example use a car radiator instead here is my design. it needs maintenance (replacing sand etc) and possibly does not give out very clean air think of a soaking substance which you can use later for something else or which you can take from nature and return to nature unharmed (like sand or mud dried up and chopped to dust)


just use a fan to suck air out of the top of the van, use hoses to exit the van, maybe even two intake places and two exits and exit the air somewhere discrete, out a wheel well, if you want to be stealthy. Use a small battery powered fan. It's really about air movement and the tremendous amount of moisture people and animals generate. It's why many serious backpackers use tarps instead of tents because tents trap a tremendous amount of moisture which can be very cold and wet whereas a tarp lets the air flow. Hence, you will be warmer and dryer in late fall with an open tarp then with a tent. If you could leave your windows open that would work or a roof vent?

I've heard charcoal briquettes will work

I am looking to slam a nice dehumidifier in my G20 van that I am converting into a house for 3 people + a cat. This is a little article I found: Make a dehumidifier. (Quick Tips).(Brief Article "I found an easy, inexpensive way to make a dehumidifier. Get two 5- or 6-gallon buckets with lids from the local hardware store (or inquire at a restaurant, which may have empty lard buckets you can get for free). New or used, clean them well. At the hardware store, get a 50-pound bag of rock salt and divide it between the buckets. With the lids off, place the loaded buckets inside the motorhome, one forward and one in the rear. When not in use, put the lids on tightly and store. When the rock salt becomes saturated with moisture, spread it out on a piece of plastic and dry it in the sun. Store it in the sealed buckets until the next use. It should last far years. I've used this method since 1937 and have not had a mildew problem." I haven't tried it yet; but I will probably go this method myself. Seems to be pretty easy and requires zero power... :)

Too bad the rock salt has to be made anhydrous in order for it to be effective at absorbing moisture from the air. This method exists in the anhydrous form of rock salt. It's called Damp Rid and I'm sure you already know about it. Just be careful that the damp rid container itself doesn't corrode when it does its thing (there are some reports of this on Amazon)

it is physically impossible for it to mildew even if you put mildew in it it would die the salt will be saltier than the dead sea as the dead sea has more water than salt and nothing lives there where as here you have more salt than water any arganism that requires any water at all will die if placed in this sort of enviroment (in time) from dehydration as the salt sucks the moisture out of it

What about taking apart a mini fridge and using computer fans to channel the air through?

I have thought of taking Silica Jell (you can buy it as various brands of descant at grocery and discount stores) and use that.

The silica jell is reusable again and again. Once it is saturated follow the directions to rejuvenate it on the container. If there are no directions, try this: take it and heat it to about 200F (97C) (I am not sure, it might need to be just above 212F (100C)) to drive out the moisture.

I think taking a box, line it with aluminum foil, put some clear glass or plastic over it, and place it so it will heat in the sun, kind of a solar cooker, would be a good 'green' way to rejuvenate the saturated silica jell. If it is easy to take out of the container, put it on a jelly roll sheet (just so there is more surface area exposed, and the sheet has a 'lip' so if it comes out it won't run off the tray.

Put the tray/sheet in the oven (or solar dryer) for a couple of hours. If there is still liquid, repeat. Once it is dry, put it back in a container that you can seal well until you want to reuse it.

You should not use the oven otherwise you'll place the water vapor right back into your house. The solar cooker has so many problems. Cloudy or raining outside? To much maintenance, etc.

 A dehumidifier... hmm... According to google it's just a thing that removes moisture content from the air. Just use a desiccant. You know those things labeled "silica gel" and "do not eat" and "desiccant". Just collect those things and distribute it around your house, although you'll need lots of 'em. But silica gel isn't the only desiccant around; I think. Another way is just to cool a tube (or similar).  The below image is my design. Red is for the inside and blue is for the outside. Red is painted black so it would absorb heat from the environment to evaporate the water inside. When the H2O evaporates it takes with it the heat which makes the vapor from the humid environment condense on the red side. It would drip to a drip pan (I forgot to include it in the image). The vapor inside the device would condense in the other side and drip back down into the red side, and the cycle repeats.  


I've seen old refrigerators used as DIY dehydrators to dry macadamia nuts in Guatemala. A dehumidifier isn't too different than a fridge designed to run with its door open.

More images are available here, and were taken during my visit to Valhalla Experimental Macadamia Nut.


I tried once using a coil of copper tubing attached to a large fan. A small aquarium pump was used to circulate ice water through the copper pipe. Ultimately the project failed - it drew too much power, was incredibly inefficient, and the ice water needed changing all the time. If anyone does make their own dehumidifier, avoid the mistakes I made and go directly to using a real compressor!

You could even avoid using the compressor and use thermoelectric ( :-) ) modules

A guy has tried it here

True, but Peltier units are at most 10% efficient, where compressors are around 40%. It would certainly work, though!

The first question to be asked is "what is the application of your dehydrator?"


9 years ago

maybe buy a fan and have it blow over pipes that have cold water being pumped through them and any water in the atmosphere should condense on the coil...(like in a refrigirator).....