Dehumidifiers extract the moisture from the room air during high humidity conditions. They help to maintain the right level of humidity that is essential for the well being of residents and also protect the household things from mould damage, mildew etc. During the hot summer, the air is felt hotter than it really is, as the high relative humidity in the air does not absorb the sweat which can be a source discomfort for the residents. Likewise, the rainy days are associated with high levels of humidity and may cause dampness inside our home which is always a bit cooler than outside.

 

To protect your homes as well as for better comfort, dehumidifiers use the age-old technique of condensation of water vapour to remove the excess moisture from the room air. Although, air conditioners can perform the same thing (i.e. removing the moisture), dehumidifiers return the dehumidified air to the room at room temperature thus you stay more comfortable in a room that is fitted with a dehumidifier.

 

There are two main types of dehumidification process – Refrigerative and Desiccant (or chemical). Most dehumidifiers dehumidify the air i.e., remove the moisture from the air using the cold and hot metal coils (refrigerative coil, hence, refrigerative type). They are ideal for use in hot, humid conditions. At lower temperatures, the coils will have deposits of frozen water that may tamper the dehumidification process. So, usually, this type of dehumidifiers may need defrost mechanisms (like hot gas defrost units or an extra heater) in such conditions.

 

Instead of coils, some dehumidifiers use desiccant substances for dehumidifying of the air. These dehumidifiers are generally much smaller than refrigerative type and used to maintain the humidity levels in smaller areas.   

 

They are of refrigerative type i.e. they use metal coils to make the water vapour condense and the water is collected in a bucket or tray during the dehumidification process.

A fan in the unit draws the room air that passes through the cold coil which extracts the excess moisture from the air. The dehumidified air gets heated when it passes over hot coil. Thus, the returned air to the room is set to the room temperature.

 

As the refrigerative type humidifiers are often prone to the freezing of coils during chill climates and very low humidity conditions, the chemical dehumidifiers are better option in such conditions.

This type of dehumidifiers use desiccant granules which absorb water from the air and once the dehumidification process is over; the desiccant materials are heated using a heater. This way, these chemicals shed the moisture and are reused again and again.

 

There are plenty of models that distinguish one dehumidifier from another in terms of size, water extraction capacity, water draining system, air flow, noise levels and extra features like hot defrost mechanisms etc.

 

Larger models usually have better water extraction capacities depending on the temperature and relative humidity (RH) levels. Generally, dehumidifiers can extract 10 to 40 litres of water during a day. Higher the relative humidity, more the unit will extract water so the suitable tank size will ensure the efficient draining system.