My dehumidifier costs to much to run, so I’m thinking about using calcium chloride to keep my basement dry(er) ALSO, this may keep my mouse problem to a minimum... my questions are -Will this be harmful to me breathing this when I’m in the basement? -Will any gases be omitted to me in my main floor? -Will this remove to much moisture that my block foundation will start to degrade? -Are there any other side effects I’m not aware of? The only person that goes in basement is me so I’m not concerned about anyone consuming it.

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    $\begingroup$ It is only harmful when eaten (and even then, not much), won't release any gases, and I don't believe you can remove too much moisture this way or any other way. That said, why do you think it is cheaper? $\endgroup$ Jun 26 '19 at 15:33
  • $\begingroup$ @IvanNeretin - perhaps they are ignoring the fact they will need to dry the material over and over again in an oven? Of course, filling the basement with calcium chloride is a good way to stop worrying about the humidity levels there... $\endgroup$
    – Jon Custer
    Jun 26 '19 at 17:47
  • $\begingroup$ ...for a while. $\endgroup$ Jun 27 '19 at 6:52
  • $\begingroup$ Actually, some commercial products intended for room drying are made of calcium chloride (scented, in some cases), so no worries. I guess it works when humidity is relatively contained, anyway: it is cheap, but you can't expect the performance of an electric dehumidifier without buying a lot of it $\endgroup$
    – The_Vinz
    Jun 28 '19 at 4:09

As for safety, calcium chloride, $\ce{CaCl2}$, is in sea water and added to foods, such as beans and pickles. It's about as dangerous as table salt, sodium chloride, $\ce{NaCl}$ (actually, $\ce{CaCl2}$ is safer for concrete).

However, it absorbs only so much water until it dissolves and stops being effective. What would you do with the puddle of $\ce{CaCl2}$ solution? It can be dried with heat and reused, but then your just moving energy usage from a continually running electric dehumidifier to a batch process using $\ce{CaCl2}$... though if you can get heat for free, it would be cost effective! If you don't have a solar concentrator or access to geothermal energy, there would probably be no energy savings, though.

  • $\begingroup$ Concrete samples have been rapidly destroyed when stored in CaCl2 solutions under certain conditions (Peterson, 1991). The most critical concentration and temperature seems to be 30 % and 5 °C, respectively. [Peterson, C.: The chemical effects on cement mortar of solutions of calcium Magnesium acetate and other deicing salts, Report TVBM-3045, Lund Institute of Technology, Sweden.] $\endgroup$
    – user482745
    Jan 18 at 12:43
  • $\begingroup$ @user482745, thank you for that concrete info. How does that compare with immersion in NaCl solution? $\endgroup$ Jan 18 at 23:00

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