Author Topic: Is it a bad idea to use silica gel to dehumidify the car I live in?  (Read 13973 times)

LifestyleDeflation

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Hey all- I'm back in sub-freezing temperatures living in my car for the winter, which means completely iced over windows every morning, requiring me to run the engine for 10+ mins every day just to keep it drivable. I do not presently have an accessory battery/solar panel setup, and I'd prefer to avoid that level of complexity if possible, so I've been looking at silica gel rechargeable dehumidifiers. I know that inhaling silica gel itself can be highly toxic depending on the additives, but I haven't had any success finding non-anecdotal data on whether regularly breathing air dehumidified by the stuff will cause any ill effects.

Does anyone know, or have an idea of where to look? I've done several searches on Google, but everything came up was talking about eating/inhaling the gel itself.

Here's the dehumidifier I'm looking at: http://www.amazon.com/gp/aw/d/B003QZ6PZ0/ref=s9_top_hm_bI6dnf_g201_i25

LifestyleDeflation

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #1 on: December 20, 2014, 08:27:35 AM »
Another solution I'm considering is finding an oxygen mask that has both input and output valves, and setting the tubing such that I breath air in from the car and out through a tube out the window.

I realize this probably sounds absurd to those of you who live more typical Mustachian lives, but I'd appreciate if you kept suggestions to change my lifestyle to a minimum- I have all my needs well beyond met, and love the flexibility my lifestyle offers me. Just trying to optimize even further- even if it makes me look like more of a weirdo. :-)

MountainBeard

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #2 on: December 20, 2014, 09:00:37 AM »
You might also look at rooftop RV fans.   I have a friend that camps out of his 4WD, and after he added one of these it resolved the same issue.

tariskat

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #3 on: December 20, 2014, 09:36:55 AM »
Assuming there are no problems with breathing that desiccated air (can't think why there would be), do you have easy access to an oven for a few hours to recharge it every week or two?  Something to consider.

LifestyleDeflation

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #4 on: December 20, 2014, 10:31:37 AM »
You might also look at rooftop RV fans.   I have a friend that camps out of his 4WD, and after he added one of these it resolved the same issue.

Thanks! I was just thinking about a fan. Given the small (subcompact) size of my vehicle, I was thinking I might be able to make do with a USB powered fan, plugged into a solar charger which could double as a cellphone charger.

LifestyleDeflation

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #5 on: December 20, 2014, 10:33:35 AM »
Assuming there are no problems with breathing that desiccated air (can't think why there would be), do you have easy access to an oven for a few hours to recharge it every week or two?  Something to consider.

I've got plenty of friends with in the area, so I don't think that would be much of a problem, though after reading more reviews of the dehumidifier I linked, I'm not sure it would be the best option, since it would require so much energy to recharge frequently.

Fuzz

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #6 on: December 20, 2014, 10:35:42 AM »
Please tell me you live to ski. I salute you. Keep us updated on what you find out.

The_path_less_taken

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #7 on: December 20, 2014, 10:49:06 AM »
Not sure about the gel but in a really enclosed environment I wouldn't trust it without solid evidence.

I'm not sure if you're 'stealth' camping in your car. But if not you could probably hang something (clothes?) as a curtain to keep the condensation off of the windows in the first place? Or even those solar folding shades they have for summer might deflect enough of the moisture to keep the car windows clear.

If nothing else, you could get a few foam/plastic placemats (dollar store) and lean those against the area you need to see out the windshield...possibly propping in place with a boot or something...and those would probably keep the moisture off the windows?

Not sure if you're opposed to purchasing anything, but there are also hair dryers that can be plugged into the cigarette lighter (presumably with the car on) which might be faster than waiting for the vents to clear the window.

Good luck. And Merry Christmas.

LifestyleDeflation

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #8 on: December 20, 2014, 03:24:17 PM »
Please tell me you live to ski. I salute you. Keep us updated on what you find out.

Snowboard ;-) Shooting for a triple digit season.

worms

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #9 on: December 20, 2014, 03:29:30 PM »
I'm not sure that the silica gel volume would be sufficient to make a worthwhile difference given the amount of moisture that you will exhale overnight.  Can't see the mask idea being comfortable or effective unless it was fan assisted.  I'd go for some form of enhanced ventilation in the car - even if it means sleeping under more blamkets to maintain the same warmth.

TerriM

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #10 on: December 20, 2014, 04:34:31 PM »
Why can't you scrape the windows?

LifestyleDeflation

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #11 on: December 20, 2014, 04:43:49 PM »
Why can't you scrape the windows?

The ice is on the inside of the windows. Most scrapers are designed for the outside, and even if I did scrape them from the inside, I'd still have to get the ice out of the car.

jawisco

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #12 on: December 20, 2014, 06:26:29 PM »
I second the idea to get more ventilation.  The winter air is dry - it will help a lot with your moisture problem. 

Unless you have insulated your vehicle, it won't make a huge difference in your sleeping temperature and you will just have to get a better sleeping bag or extra blanket.

Jack

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #13 on: December 20, 2014, 07:05:35 PM »
I realize this probably sounds absurd to those of you who live more typical Mustachian lives, but I'd appreciate if you kept suggestions to change my lifestyle to a minimum

Given the small (subcompact) size of my vehicle...

What kind of car is it? Off the top of my head, I can't think of any subcompact vehicle that I could lay down flat in. Not to criticize your lifestyle, but surely something like a minivan or station wagon would be more comfortable (and not much less efficient)...?

Why can't you scrape the windows?

The ice is on the inside of the windows. Most scrapers are designed for the outside, and even if I did scrape them from the inside, I'd still have to get the ice out of the car.

Tape a sheet of plastic to the trim along the bottom of the window. Hold the opposite edge up, so that when you scrape the ice is caught by the plastic. Then roll the window down, lift the edge of the plastic some more and flip the ice out of the car.

Daley

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #14 on: December 20, 2014, 07:35:26 PM »
I'm not sure that the silica gel volume would be sufficient to make a worthwhile difference given the amount of moisture that you will exhale overnight.

Worms has a point. Someone over at Amazon already did the rough math on how much water this canister can actually hold. That quantity? Approximately 180-260ml of water, and there's adsorption rate decreases as it hits its holding limit under the moisture conditions. Another feller from that same page reported that the beads change color after adsorbing as little as 60ml of water. Now, the next question is, how much water does the average human exhale? Well, the Medical University of Warsaw did a study on that. Supposedly, a body at rest in the ballpark temperatures you're dealing with can produce upwards of 20ml/h.

Safety isn't really the issue here, because the silica isn't being ground up and blown into the air. The real issue is the basic math. At best, you'd probably need to dry it out every 3-4 days, at worst, daily... and it might still not be enough to keep the ice off. Your best bet is going to be some sort of simple active ventilation system like a car window fan blowing out instead of in. Unfortunately, it will drop the ambient temperature of the cab that much lower, and the drier cold air could also cause minor respiratory and sinus issues itself.

LifestyleDeflation

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #15 on: December 20, 2014, 08:16:28 PM »
Thanks for the thoughts and suggestions, all.

I'm in a Honda Fit. I built a platform for it in such a way that I can fold down the front and back seats, then use the full length of the interior to slide out a second piece of plywood, so the total size of the flat sleeping platform is actually larger than a twin sized bed. On top of that, I have a very comfortable inflatable and heat reflecting mattress.

I'm going to look into buying a solar usb charger, and using a usb powered fan for ventilation. That way, I get  a weak fan to help with the humidity without overwhelming me and the charger can double as a cellphone charger.

Since I won't need to rely on my car battery as much to charge my phone and I won't need to run the engine to de-ice the windows, I may well actually be able to leave the car off for weeks at a time!

MacGyverIt

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #16 on: December 20, 2014, 09:34:28 PM »
I have a very comfortable inflatable and heat reflecting mattress.

Mind providing the make and model? I'm interested in investing in such a mattress.

LifestyleDeflation

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #17 on: December 21, 2014, 03:26:36 PM »
I have a very comfortable inflatable and heat reflecting mattress.

Mind providing the make and model? I'm interested in investing in such a mattress.

Big Agnes Q-Core. It's the most comfortable backpacking mattress I've ever slept on, though I question its durability. Luckily, using it in the car doesn't put it in much danger of a puncture. Here's the one I have: https://www.bigagnes.com/Products/Detail/Pad/qcore

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #18 on: December 22, 2014, 09:32:00 AM »
If you want to use silica gel just buy bulk, or buy multiple units on sale. My last purchase for silica gel was $94.05 for 2.5kg of indicating gel, $69.35/2.5kg for non-indicating gel (work use). I mix some indicating in with the non, when my blue stuff goes white I dry the whole batch. I routinely add 10-20% water weight into my gel before drying it, I dry it before it's saturated.

If one doesn't work you can buy 5, the system is scalable.

For drying I regularly use a casserole dish in the oven or microwave. It's fine to microwave (in a microwave safe container), 500 grams should be done in 5 minutes, that's what the indicating gel is for though to tell you when its done. It smells a little weird, like drying sand, that's normal.

Be careful if the gel gets dusty, the dust is bad for the lungs, it's very important to read the MSDS on this one for handling instructions. when you constantly mix/pour it gives off dust, the rest of the time it's harmless.

Mother Fussbudget

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Re: Is it a bad idea to use silica gel to dehumidify the car I live in?
« Reply #19 on: December 22, 2014, 02:34:32 PM »
Is there enough sun where you are to make one of those $10 Jobar (IdeaWorks) Solar car window fans practical?