Guide to Choosing a DehumidifierWritten by Duncan under Dehumidifiers, Desiccant, General | 2 Comments
One of the most important factors to bear in mind when choosing a dehumidifier is the need to match the water extraction capacity of the unit with the requirements of the place where it is going to be installed. Obviously, larger rooms require dehumidifiers that are capable of removing large quantities of water efficiently in order to achieve and maintain the RH (relative humidity) of the room air that you desire. Beware though, as the stated capacity of any dehumidifier is calculated using the baseline of a very high humidity and temperature. If a dehumidifier claims to be a 20 litre unit, it may extract 20 litres in a dripping tropical rainforest, but may not achieve that in the UK climate!
All dehumidifiers use mechanical energy to move air, so they do tend to make a certain amount of noise that comes from the compressor mainly in refrigerant models and even desiccant units use fans to draw in air. However the latest models are certainly far quieter than their predecessors. Many top end models also have a frost protection feature using a hot gas system to defrost the internal cooling coils so they can be used in cold weather, however their efficiency can be diminished at very low temperatures.
For very small spaces like wardrobes, cupboards, sheds, caravans, boats or garages, a desiccant moisture absorber should be sufficient, especially if these locations don’t have a power supply. The Superdry moisture absorber for example contains desiccant that will absorb up to 1.5 litres of water from the atmosphere for up to eight weeks at a time.
Larger rooms may require a dehumidifier that can extract around 20 to 40 litres of water every day, especially during very humid days. If smaller rooms need to be dehumidified, half that capacity should be sufficient so a product like the GD10L 10 Litre dehumidifier would be perfect. This compact and economic unit has a continuous drain option so a hose could be fitted to take the water directly to a drain, thus by-passing the automatic shut off many of these more compact units have when their relatively small tank is full.
Tank size is definitely a consideration to take into account. The dripping water from a dehumidifier is collected in a tank which has to be emptied periodically. Obviously, the smaller the tank, the more frequently it needs emptying. Some compact units can be surprisingly efficient with powerful little dehumidifiers that can remove up to 20 litres of moisture every 24 hours. That’s adequate for a 3-4 bedroom house or a humid cellar or garage. These units incorporate an integral water container or can be connected to a drain for continuous discharge.