Desiccant or compressor driven dehumidifier?Written by Duncan under Dehumidifiers | 5 Comments
The two main types of dehumidifiers for the home and light commercial area incorporate either desiccant or compressor technology to remove moisture from an atmosphere.
A desiccant dehumidifier contains a material that absorbs the moisture directly from the air and then releases it into a tank when it is warmed.
A compressor driven dehumidifier is the more traditional type and works by creating a cold surface upon which moisture from the air is condensed – just as moisture forms on a cold glass on a hot day. This condensation then runs from the cold surface in the dehumidifier into a water tank at the base of the unit.
Both types work very well but both have disadvatages and advantages. As the desiccant dehum doesn’t need to contain a compressor they are normally very light and easy to handle, whereas compressor driven models tend to be quite heavy. However, as desiccant models need to produce heat to extract the moisture from the air they require more power to run than a compressor driven model so can have higher running costs. They also tend to be more expensive to buy initally.
A major advantage of using a desiccant dehumidifier is that they are very effective at low temperatures. A compressor driven dehumidifier is less effective in a cold room as cold air doesn’t condense as easily on a cold surface as warm air does. This means that in warm areas above 20 degrees compressor driven models are very effective but as the temperature drops so does their ability to remove lots of water from the air. As the desiccant model isn’t affected by temperature, it can extract roughly the same amount of moisture at 5 degrees as it can at 15. If you are looking to dehumify a garage or shed then desiccant is definitely the way to go.
However, neither type will function in freezing conditions. Some compressor driven models incorporate a “Hot-gas defrost” feature. This doesn’t mean they can dehumidify in freezing temperatures, rather they defrost the ice that forms internally at colder temperatures more quickly so perform better than other compressor driven models without this feature. Even hot-gas defrost models can’t compete with desiccants at very low temperatures though.
Lastly, as the compressor driven model requires refrigerant to function, it could be said that desiccants are the more environmentally friendly option, as they require none. Although, it could be argued that as desiccants consume more energy when operating, the benefit of not using refrigerant gas is outweighed by the increased carbon footprint it has over its lifetime.