You can use Calcium Chloride to remove moisture from the air. Calcium Chloride is a strongly hygroscopic (desiccant) compound meaning it has a strong attraction for water. It can absorb as much as twice its own weight in water making it very useful as a drying agent.
Calcium Chloride is available as a deicer salt that can be easily found in stores this time of year. It is best to use pure Calcium Chloride rather than using it as a blend with other deicer salts (which may not be as hygroscopic).
Find deicers that list only 'Calcium Chloride' as an active ingredient. It is also commonly listed under its chemical name: CaCl2.
It costs me roughly $10 for 10 lbs of salt.
It can be sprinkled in a shallow container with a large area, as shown in the figure below. I placed a pan underneath the container to avoid any potential leaking onto the floor. In my case the salt was mixed with traction sand, a common practice for deicers, but not necessary for use as a dehumidifier. 
To increase the rate of water absorption you can place a fan near the container, facing towards it. The flow of air over the Calcium Chloride will help it to draw in more water from the air. See figure.
After 2-3 days it should be completely saturated with water (see figure). You can replace it with new salt and pour the old brine into a metal container, which can be placed over an outdoor barbecue. The high heat will evaporate the water allowing you to reuse the salt.
Since the salt can be reused, and fan and evaporation costs kept low, this is likely a cheaper alternative than using an electric dehumidifier.
Related posts:
Removing Moisture From Windows Using Calcium Chloride
Natural Dehumidifier Continued
13 comments:
thanks for the info - it sounds awesome. i am looking forward to trying it out in my damp damp basement!
Unbelievable...Our basement is 1400 square feet. I've been running a dehumidfier 24/7. Still have mold and mildew problems. I put a pie tin of calcium cholride in both ends of the basement, by morning they were both overflowing. I had to use collanders w/ 5 gallon buckets to accomodate. CAN THE WATER BE POURED DOWN THE DRAIN?
That's great! Your basement must be very humid.
Yep, you can pour the calcium chloride brine down the drain. It's non-toxic. But you might want to dilute it with some water first.
But you can also boil off the brine instead and re-use the calcium chloride if you want. That's what I'm doing.
Thank you for a straightforward, inclusive article. We are leasing a property that acquired some flood damage last year (in Iowa... corn anyone?) and had been battling the resultant moisture from an elevated water table. As someone else stated, even with a brand-new humidifier running 24/7, we still couldn't get the area as dry as we'd have liked. It's difficult to eradicate mold without a serious reduction in humidity. Your process FINALLY got us up over 'the hump' that was mustiness.
How to reuse that salt for dehumidifying ?
Thanks
Could pouring the brine down the drain have a negative effect on a septic tank system?
^^^ Good question. I would say no since Calcium Chloride itself is not toxic to the environment. Plus it would probably be in such a low quantity relative to the size of the septic tank that it won't have an effect. But if you want to be sure talk to septic tank manufacturers and see what they say.
How about water softener salt. It may be too large, I would expect the increase surface area of a deicer type salt would be superior. Your thoughts?
^^^ You would have to see if water softener salt is hygroscopic, meaning it attracts water. But I suspect it won't be nearly as good as calcium chloride.
You can always try it out!
Thanks for the great idea. I live in a basement apartment and the humidity level is over 90%. This concentrated ice melter used for driveways is already starting to gather moisture and its only been a couple of hours...
Yeah thanks for this info. I just went and grabbed some at the local hardware. I got Dow labs 80%+/- pure and I set a pan down with some in there and 10 minutes later it already has droplets on top of the flakes. 50 pounds for $10. Good stuff!
Is this the same stuff as "ice melt"? I notice that when I type in calcium chloride in google it comes up with ice melt type stuff.
Thanks!
^^^ Yep, it's ice melter.
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