Basically, there are two types of dehumidifiers such as Desiccant dehumidifier's also known as passive dehumidifiers and Mechanical dehumidifier's also known as active dehumidifier's.

The Desiccant dehumidifier's attracts towards the water vapor. The process involves around exposing the matter to air stream along with a relatively high level of humidity. Also, they do not use compressors. They can be used best with low levels of humidity and temperature. The major advantage of these dehumidifiers is that they are very much cost effective.

The Mechanical dehumidifier's are the most commonly used type. They are also very efficient and the design factor includes a simple air conditioner with both cold and hot coils places in the same box. The mechanism of these types is fan absorbs the room's air through the AC's cold coil which is collected in a bucket, for condensing the moisture. Then, the hot air is passed through the hot coil for heating up to its original temperature.

There are a few things to consider while buying a dehumidifier. They are:

* Size: The dehumidifier size is most important factor to consider while buying. It is usually determined by the amount of moisture extracted from the air, for the time period of 24 hours which is often calculated in pints. Always, go in for a larger capacity model.

* Portability: Choose lightweight and compact dehumidifiers which have a handle and rolling casters for moving it to any place you wish to.

* Automatic Shut-Off: This is key feature as it averts overfilling and allows it switch on or off without unplugging it.

* Storage Tank Capacity: 15 pints tank size is ideal.

Apart from this washable air filter, continuous drainage, and defrosting option are the other features you can have to look on.