Dehumidifier for distilled water

RalphLambrecht

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I recently bought a dehumidifier for the room where I store my camera equipment, and it generates about a liter of water per week. Can that water be used as distilled water, and is it the same as distilled water, or is distilled water "cleaner" yet? Cost is irrelevant because distilled water is extremely inexpensive, but if it can be used safely, why throw it away?
 

SMD

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If you consider the damage it can cause, it is less expensive throwing it away. Is there no dust in it?
Real distilled water is not that cheap. What you usually can buy labeled as such is in reality demineralised.
 

Romanko

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I would not bother. It might contain tiny dust particles and other stuff you don't want in your solutions. You can always use it to to wash your lab equipment. Distilled water is cheap and film is expensive, so why risk it?
 

Don_ih

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Like @Romanko said, that water will contain dust. It is pretty much distilled water but the method of condensation drags dust in as well. You will find that, after a fair amount of time, the inside of your dehumidifier reservoir gets a bit scummy. The water you get from that is not good for film.
 
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RalphLambrecht

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Romanko said:
I would not bother. It might contain tiny dust particles and other stuff you don't want in your solutions. You can always use it to to wash your lab equipment. Distilled water is cheap and film is expensive, so why risk it?
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Where should the dust come from?
 

DREW WILEY

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Distilled water means steam distilled. It is not the same as deionized. Both are clearly labeled as such, and cost about the same per gallon here. You can also buy your own water distiller; but they're energy intensive. What dehumidiers do, instead, is capture surrounding water vapor, which is full of various spores - including water mold spores - plus tiny dust particles, then concentrates that as liquid. Water mold (Saprolegnia) is almost everywhere, and will even grow in many dilute developer solutions, stop bath, and fixers if they are not capped off. It can be filtered out; but that's a headache. Or toss a little Listerine (the thymol variety) into your solutions, and hope that doesn't itself mess up the performance. I just pick up a few jugs of commercially distilled water instead when I visit the supermarket. Typically around a dollar a gallon.
 

grahamp

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California suppliers will usually provide a breakdown of their methods and water analysis. When I costed the running of a kitchen distiller, the electricity cost here was close to the cost of buying it. I keep a few gallons in stock because we need it for a medical device anyway.
 

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Sirius Glass

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When I liked in a house with a dehumidifier there was always dust in the water. Set up a double distilling set up and you can have all the distilled water you want.
 

petrk

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I use it. Always filtered as I would do with a tap water.
 

mshchem

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Dehumidifier water can get some pretty ugly mold going. IMHO it's not worth the effort. There's a lot of filth that can collect on the coil. YMMV
 

MattKing

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RalphLambrecht said:
That must be very minimal. The cooled rod from which the condensed water drops sits in no more than a dm^3 of air, but I will check with a microscope.
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Don't forget that the air that the water is extracted from contains lots of dust, and that extraction process would be likely to concentrate any solid material in that air.
 

koraks

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mshchem said:
Dehumidifier water can get some pretty ugly mold going.
Click to expand...

This

Romanko said:
It might contain tiny dust particles and other stuff
Click to expand...

This
DREW WILEY said:
What dehumidiers do, instead, is capture surrounding water vapor, which is full of various spores - including water mold spores - plus tiny dust particles
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This

It's all true.

We have a dehumidifier and I run it frequently to keep RH low when we have laundry drying, and I also use it to speed-dry carbon transfer tissue. Initially I thought that the water would be fine for washing film - and really, it sort of works for that purpose. Like you, @RalphLambrecht, I was skeptical at claims that it would contain dust etc. (here's an apology to those I didn't believe!) However, over time, I learned that the water from our dehumidifier isn't quite as clean as it 'should' be. It does contain dust, and it doesn't take a microscope to see it. And it does indeed grow mold if let to sit for a while.

mshchem said:
There's a lot of filth that can collect on the coil.
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This is part of the problem; it gets worse over time. Another part of the problem is that the filter in a typical home dehumidifier is pretty coarse, so a lot of dust gets through unhindered.

You can still use it to mix developer etc if you don't mind the dust and the mold. I personally don't bother and just use tap water.

RalphLambrecht said:
if it can be used safely
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It's excellent for watering potted plants.
 

Rick A

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Personal experience running a dehumidifier, mildew/mold spores in the water. If mold and/or mildew are present in the space it ends up in the collection tank. I check my tank every time I empty it for signs of growth, occasionally some shows up and I have to spray my basement with fungicide. As for dust particles everyone is concerned with, there's more particulates in tap water.
 
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RalphLambrecht

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MattKing said:
Don't forget that the air that the water is extracted from contains lots of dust, and that extraction process would be likely to concentrate any solid material in that air.
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I must be a bit dense, but I don't get where you see a source of dust. Anyway, the microscope doesn't show anything; clear as glass.
 

koraks

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RalphLambrecht said:
I must be a bit dense, but I don't get where you see a source of dust. Anyway, the microscope doesn't show anything; clear as glass.
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Ralph, I've been running a dehumidifier for years. I tell you, the water isn't clean. It might be now that your dehumidifier is brand now, at some point, it won't be and it'll have muck in it. You either believe it or you don't, IDK. I don't really feel like going to the lengths of posting photos of the slimy mold and the dust that floats around in it. If you don't believe people who use these machines, then I don't think showing any other evidence is going to make any difference.

Feel free to use your DIY condensation water for whatever purpose you see fit. I've rinsed film with it alright. It doesn't leave the film clear unless I wipe it. I get the same cleanliness if I use tap water. YMMV.
 

ic-racer

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The water the comes out of my dehumidifier is clean and suitable for film rinsing or mixing chemistry. Yours may be the same.
 

Willyekerslike

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RalphLambrecht said:
I must be a bit dense, but I don't get where you see a source of dust. Anyway, the microscope doesn't show anything; clear as glass.
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If you have lived a few decades and been happy not knowing where household dust comes from l would leave it at that. However, I will just mention that one of the contributors to household dust is the people that live in the house. Dead skin particles which we are loosing all the time, night time is when the mites gather to feast on this this bounty we provide. You do have a H.E.P.A. filter in your hoover......
Live long and prosper.
 
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RalphLambrecht

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ic-racer said:
The water from my dehumidifier is clean and suitable for film rinsing or mixing chemistry. Yours may be the same.
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Mine is, too, and I may use it, but the argument of eventually developing slime in the water tray is indeed worrisome.
 
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RalphLambrecht

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You are right; I won't believe it until I see some evidence. Nevertheless, I thank you for your input and sharing your expertise.
 

Don_ih

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RalphLambrecht said:
You are right; I won't believe it until I see some evidence.
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I think the point of what Koraks was saying is that, since you don't believe what people who have experience using these dehumidifiers are saying (except those that say the water is perfect), you likely won't believe any evidence supplied by them, either.

The machine blows air over a coil, causing condensation. Dust in the air also ends up in that water. It's not the same as steam-distilled water. Whatever is in the air is also in the water.
 
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RalphLambrecht

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Thank you for the theory. However, it's not supported by my observation.
 

koraks

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RalphLambrecht said:
However, it's not supported by my observation.
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Your single observation.
We've had our dehumidifier for years. It has produced hundreds of liters of water. Most of it I 'harvested' and initially I've used quite a bit of it in the darkroom. A few observations made me think twice about the purity of this water:
1: It smells of our washing detergent, despite never having physically touched anything that has been in direct contact with the detergent. At least some volatile compounds are dissolved in the water.
2: I used to feed our steam cleaner with this water, until the fine-mesh filter in the cleaner clogged. The culprit was a mat of fine dust (easy to miss on visual inspection of the water) combined with a transparent, colorless, slimy bacterial cake. This does not grow on store-bought demineralized water, but it seems to do fine on our 'home made distilled' water.
3: If I keep the dehumidifier water in a clean jug (that held factory-made demineralized water), it'll develop strands of near-colorless 'floaters'. If the water were pure, this would not be possible - the stuff has to grow on something other than pure H2O.
4: The condensation behavior of the dehumidifier water is different. Again, side by side in the same kind of vessel as store-bought water, it's easy to see how the dehumidifier water creates condensation in the jug while the store-bought water sitting in the exact same spot under the same condition doesn't. IDK why this happens (consistently!), all it does tell me is that something is going on in the dehumidifier condensate that doesn't occur with store-bought demineralized water.

Most of this I ever noticed when our dehumidifier was relatively new, apart from the smell (which really should have been a clue). Maybe some of this didn't even happen and only became an issue as time went by. The condensate touches several parts of the dehumidifier. Expecting that these parts remain sterile over the lifetime of the machine is ludicrous - of course stuff will cake and grow on to it.

You just bought your machine, had a single look at the water and decided it was clean, and based your conclusion on that. It's like crossing the street blindfolded and making it to the other side alive only to conclude that surely, there's no traffic, ever, on this particular street.
 
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