I just bought a Nissan NV200, which I've had outfitted with a partition and shelves. My tools stay in the vehicle and after a really cold night, I find a fair bit of condensation on them.

I've tried running the defrost on high, even the AC to dehumidify, but until the tools warm up, they'll collect whatever moisture is in the air.

How do you manage moisture in your vehicles ?

  • If they get really cold overnight then you take them into a warm, humid house, they'll get plenty of condensation on them however dry the van is-would this affect you? In any case putting them away dry in a closed tool box should help, especially if you close the lid when you're not getting something out. You can buy 12V dehumidifiers with Peltier coolers, but I've never tested one.
    – Chris H
    Jan 18, 2017 at 17:51
  • 3
    I'm voting to close this question as off-topic because it isn't about home improvement, or even home tool storage.
    – isherwood
    Jan 18, 2017 at 17:59
  • That said, I'm in one of the worst climates for tools, and it's rarely a problem. Once you hit the jobsite, leave the doors open for a while so you get good ventilation. Consider an interior job box if on an inside job.
    – isherwood
    Jan 18, 2017 at 18:00

5 Answers 5


As you said, until the tools warm up, you will have condensation problems. Cold tools and warm air will always give you condensation problems. The only option is to prevent your tools from getting that cold.

Using heat to protect expensive/precision tools is nothing new and is commonly done to preserve firearms. I use this GoldenRod heater type dehumidifier http://amzn.to/2utHyWQ to protect machine tools with exposed metal surfaces like lathes from the dangers of condensation corrosion. I have even seen these heater bars used on pianos to protect the wooden structure.

I suggest you place them in or under your tool racks and leave it plugged in overnight. These simple resistance heaters can also be hooked up to a 12v line, though it would most likely only output 10% of the original amount of heat when done so.

Then again most of my hand tools and even the vast majority of my power tools seem to be unaffected by condensation/moisture/rain. The only things that get their own heater are the expensive precision tools and measuring devices.


What you might want to try is adding a cabinet with a gasket around the door, then add some Damp-Rid packs inside to absorb any humidity (they sell a closet pack you can hang from the top). It's not terribly expensive and dehumidifying such a small space shouldn't cost a lot


Place chalk sticks in tool boxes to soak up moisture.


Go to the store and buy a bag of ice-melt. Calcium chloride is a great desiccant and it is quite cheap.

Place some of it in cheesecloth, old pillow cases, or tee shirt material. Put it in with your tools.

Problem is it will need to be renewed occasionally.

Good luck!


Weird. I've never had that problem, except in cars that leak or have standing water inside for some reason. Then I have the problem bigtime, so severely that no workaround will work.

For instance last winter I suddenly got rust blooms. Digging into the spare-tire well, I found 10mm of water in the bottom. Mucked it out, problem never returned. (and I don't have A/C, so A/C dehumidify is not available to me.) Turns out in a visit to the snowbelt, I had hauled some stuff that had been laying on the ground and was encrusted in snow and ice, and some melted.

So the big question to me is...

Where's the water coming from?

One-time spill, as in my case. Assures 100% relative humidity, causing repeated problems until addressed.

Water leaks. Even a tiny leak can do a lot, even if it hasn't rained - it is letting condensation on the outside of the car inside.

Wet clothes, often. If it rains or snows a lot, your shoes and clothing can bring it in, especially if you take it off and leave it in the truck.

Exhaust leaks. Engine emission controls these days are asymptotic to perfect, so there isn't much carbon monoxide etc. left to kill you. However there's an enormous amount of H2O (water), with exhaust over-saturated with water. As it cools, it must condense.

Faulty air valves bringing in saturated air from outside. Cars should leak air just enough that people sleeping in a car don't get CO2 poisoning. At full highway speed, the venting is designed so aerodynamic forces force a small amount of air through your ventilation system, enough to push out a possible exhaust leak. Of course the blower needs to work on full. However the car shouldn't be drafty. One compromise is done with passive, one-way air flapper valves in certain places. You might check the health of those valves, if equipped.


I honestly think you must have one of the above problems, and the answer is fix it.

However if you are at wit's end, it may be worth looking at a dehumidifier. A desiccant dehumidifier can be small and work well at low temperatures and pull relative humidity down to near zero. I don't know whether this can be sized to an auxiliary battery fed by solar. It takes a lot of power for its heater, so you may need to plug in.

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