Before choosing a dehumidifier for your home/office, it is important that its water extraction capacity should meet the requirements of the place where it is going to be installed. As a rule of thumb, larger rooms require dehumidifiers that are capable of removing large quantities of water efficiently. Secondly, the relative humidity of the room air and the climatic conditions are the factors that should be considered before choosing the suitable dehumidifier.

The relative humidity of air (RH) in your room indicates the moisture content in the air. Higher the RH, the more water vapour in the air. Generally, 40 to 50 percent RH makes us feel comfort and also protect us from many health hazards related to high humidity.

With higher RH levels, you need to make sure that your dehumidifier has the enough capacity to extract water to maintain the required RH level. For instance, a 40 or 50 pint dehumidifier is what you require, when you want to use at places which have more than 70 % relative humidity.

In the same way the relative humidity and temperature levels affect the performance of the dehumidifiers, the room size or area that you plan to dehumidify also becomes a criteria while choosing a dehumidifier. There are various water extraction capacities available with dehumidifiers. For example, a larger room may require a dehumidifier that can extract 20 to 40 litres or up to 65 pints of water every day, especially during very humid days. If smaller areas need to be dehumidified, half the capacity of this can be sufficient.

The dripping water from the dehumidifier is collected in a tank which has to be emptied periodically. The smaller the tank, more frequently it needs emptying. So, it is a good idea to choose bigger tank with your dehumidifier, as it can be emptied of water on daily basis or once in every two days. The smaller tank has another disadvantage too. Once it is full and not emptied, the unit may shut off till the water is drained.

Since dehumidifiers use mechanical energy and move air, they tend to make noise to certain extent. While choosing a dehumidifier, make sure that you are informed on the noise it produces. The latest models produce much less noise than their predecessors so you may find the suitable dehumidifier with noise levels acceptable to you.

Dehumidifiers have filters that remove the dust particles from the air before it is passed through coils. By removing the dust, filters make the air pure as well as protect the coils from wear and tear. However, filters will get deposited with layers of dust over the time and they need cleaning periodically, especially, if the filters are washable. You can choose disposable air filters that you can change after certain time.

During extreme cold climates, the coils in dehumidifiers get frosted and the dripping of water completely stops and they may grind to halt. To prevent this, you can add the hot gas defrost unit to the standard unit. When the water gets frozen on the coil, the coil is heated and the ice melts away. Some standard units also come with an extra heater that prevents water vapour from getting frozen on the coil.