Build Your Own Humidifier Using Rock Salt Image 1

Build Your Own Humidifier Using Rock Salt

It’s that time of year when it’s cold outside and warm inside causing huge amount of condensation on your windows and window sills. In this blog we take a look at how to make your very own cheap and easy humidifier using rock salt and a couple of containers.

It’s a surprisingly little known fact that salt can be used to absorb moisture from the air. On a small scale, and with a little preparation, it’s not too difficult to put together a container that holds salt, which functions as a basic dehumidifier in the home. It’s not something that can be 100% reliable but if left close to a window it can help absorb moisture as it condensates on the cold glass.

Making a rock salt dehumidifier is also a fun home science experiment and is useful to help teach kids about one of salt’s properties. Other salts used for deicing or antifreeze crystals are also available online which function as an even more effective dehumidifier, and can work in the same way and can teach a little extra bit of chemistry too.

Building Your Humidifier

The easiest way to construct a dish in which salt can collect water is to place a plastic bowl with a hole in the bottom over the mouth of a similarly sized bucket or basin. If the salt manages to collect enough water it should drain into the bucket below through the hole. It’s possible to put together something fairly simple with tape and some empty plastic food cartons or bottles as seen in this diagram.

If you try anything on a larger scale, the principle is very much the same – you could even use full sized buckets, making sure the first has a drainage hole. Also a fine sieve may work a little better at making sure the salt doesn’t drain out of the top container’s drainage hole. A small piece of pipe mesh may work as well.

The types of rock salt that can be used vary. Some types are more reddish in colour and look a little more decorative if you manage to create a fancy looking design, or if you’re going to place fancy salt in a decorative bowl, which works in its own way. Other salts are brighter and whiter, and may be better at their job as they contain fewer impurities.

The Science

Salt is a hydroscopic material, which means it pulls water molecules out of the air around itself and can even store them up to the point it becomes fully hydrated. It’s not just table and rock salt (sodium chloride) that does this – there are other chemicals which are known as salts and they may also have this effect.

This is why other industrial salts may be more efficient in your dehumidifier. A product used for de-icing paths may contain pellets of non-hydrated calcium chloride – another salt which is also very effective at pulling water out of the air. This salt is different to table salts, but can be used in exactly the same way in your homemade dehumidifier. It’s available in small portions online, so if you’re interested in trying this experiment out, give it a go.