Demystifying dehumidifiers
A dehumidifier is a great idea for keeping the boat, caravan or car dry and free from mildew while it's laid up for the winter, but most kinds just don't work at low temperature.
The perfect boat dehumidifier?
Refrigerant dehumidifiers
Most dehumidifiers work on the refrigeration principle. Moist air is drawn over a refrigerated element where water vapour condenses and is drained away. That's great in a warm climate, but below 15°C, efficiency falls off and the refrigerating element can ice up. They become ineffective just when you need them most!
Dehumidifiers with automatic defrost capability are sometimes recommended for use in cold spaces. It's true that they overcome the problem of icing up, but their efficiency is greatly reduced in cold conditions.
Check the spec!
If you look at the specification of most dehumidifiers, the extraction rate is quoted at 60%RH and 30°C. This gives a good indication of how it will perform in keeping a room comfortable in a hot, sticky climate. To keep your boat free from damp during a typical British winter, you need to know what it will do at around 10°C or less. You won't find that information for a refrigerant dehumidifier - you need a completely different technologyl!
Adsorption dehumidifiers
Adsorption dehumidifiers are different. They work like this:
- Moisture from the air is attracted to a desiccant carried on a rotor.
- Moist desiccant is carried around to a drying sector, where gentle heat drives the water off and into a reservoir.
- Dry desiccant moves around ready to take more water from the air.
This technology works well at all temperatures and efficiency is much better than a refrigerant device. There's no cooling effect and no compressor, so practically all the energy used escapes as heat, giving a very gentle warming effect.
The adsorption system has previously only been cost-effective for large commercial applications, but the principle has been developed into a brilliant new dehumidifier that we think is pretty well perfect for keeping a boat dry through a typical British winter.
The perfect boat dehumidifier?
Follow this link for information on the perfect boat dehumidifier.