3 Types of Moisture Absorbers Explained

A close-up image of moisture droplets on a glass surface.

Moisture absorbers are very helpful in homes, especially because they inhibit the growth of mold and mildew. Mold usually grows in damp areas, such as the basement, the kitchen, and the bathroom. To solve the problem of mold, moisture absorbers placed in packets or buckets can help remove the moisture in a room or enclosed space. There are three main types used commonly today, and each has its own unique properties that can be used for different purposes.

1. Silica Gel

Silica Gel is a moisture absorber made from sodium silicate. It has a high specific surface area which makes it a a very powerful desiccant or drying agent. Its name may be misleading because this form of silica is actually solid, produced in a beaded or granular form. The process by which Silica gel removes moisture from the air is called adsorption. This means that the Silica attracts moisture onto the surface of its numerous pores rather than absorbing moisture into the bulk of itself.

Silica gel should not be ingested, as it is a poisonous substance, and to ensure that the product does not get eaten, manufacturers usually place a warning on the silica gel’s plastic container.

Silica gel has a very strong adsorption quality when used in room temperature. However, it may give up the water it holds when exposed to temperatures near or higher than 40 degrees Celsius. Since silica gels are quite expensive, they are not recommended for use in larger areas such as basements and kitchens.

2. Clay Absorbers

Clay absorbers offer a cheap alternative to absorbing moisture in a home or in any other space where moisture leads to molds. Some homes that make use of clay bricks often do not get moldy because the moisture absorbent qualities of the clay remove the dampness that increases mold growth.

There is one disadvantage to using clay, though. Its moisture absorption property is very low as compared to the other two types. For heavily humid areas, clay absorbers are not recommended. Other alternatives include coal, charcoal, rocks, and rough gravel.

3. Calcium Chloride

Perhaps the best moisture combatant is calcium chloride, a mixture of chlorine and calcium. It has a very strong moisture absorbent property that makes it an ideal candidate for high humidity moisture absorption projects. Calcium chloride is usually used in shipping goods and does a good job in keeping these goods dry during the whole duration of the trip.

For very humid basements, kitchens, cabinets, closets, and other spaces, calcium chloride does provide effective moisture absorption. Sometimes, an electric fan can make the dehumidifying effect of the compound a lot faster and more widespread. Place the fan over a bucket of calcium chloride, and the motion of air will allow the moisture to circulate above the compound.

As an alternative, rock salt can also be used in place of calcium chloride. Although rock salt is not as powerful, it does provide an effective alternative that is both cheap and easy to access.

Calcium chloride should not be ingested as it can cause burns in the mouth, throat and intestines. It can cause vomiting, serious dehydration as well as severe dryness to the skin. Contact with eyes must be avoided and hands should be washed thoroughly after handling.

Moisture Absorbers Explained FAQ

Do moisture absorbers really work?

Moisture absorbers really do work to reduce moisture levels in an indoor environment. They literally do absorb moisture in the air to make everything feel dryer and keep the atmosphere healthier.

Where is the best place to put a moisture absorber?

Place moisture absorbers as close to the source of humidity and moisture as possible. You don't want to place them near windows and doors, where they might absorb outside moisture rather than the moist air indoors.

How many moisture absorbers do I need?

You don't know how many moisture absorbers you need until you start trying to use them to remove moisture. Place just one or two moisture absorbers at first.

If you find that you need more, you can always add more. The number of moisture absorbers you need depends on the size of the space and how moist it gets.

How long do moisture absorbers last?

Moisture absorbers will stop working after a while. How long they last depends on how much moisture they're absorbing, but they will typically last around 60 days before they need to be replaced.

What causes too much moisture in a house?

Simply living a life causes moisture in the house. Taking showers, using the washing machine, cooking, all of this can cause humidity in the air.

However, if this is an ongoing problem then the moisture is most likely due to poor ventilation in the home. It could also be caused by a water leak, so it's worth it to find the source of the moisture and make sure it's not a signal of a much bigger problem.