Dehumidifiers – What They Are & Why You Need One For Storing Your Car!
As the “summer” picks up the tail ends of its skirt and heads for the equator, many owners of classic or “fair-weather” vehicles are putting them into car storage for the winter months. Often the storage location is unheated, so whilst it offers protection from road salts and winter weather it does not protect from the damaging effects of damp. And this is where dehumidifiers are a brilliant idea!
One of the most comprehensive solutions to the repercussions of damp is the dehumidifier, so the UF team decided to take a look at the effectiveness of desiccant and compressor dehumidifiers and their use in combating damp in car storage units.
Damp produces mould and mildew on convertible soft tops and upholstery, ruins rubber seals and rusts metal parts including brake discs! Dehumidifiers remove excess moisture from the air and so help prevent this from happening. Dehumidifiers also eliminate that dank, musty smell common to enclosed spaces – open the door on your first visit back in the spring and it usually hits you on the nose!
So a dehumidifier seems a great idea, but there are two different types on the market – the desiccant and the compressor. So what’s the difference and which one is best suited to your needs?
How Do Dehumidifiers Work ? The Technical Bit !
Desiccant dehumidifiers use an absorbent material to ‘suck’ the excess moisture from the air. A fan draws the surrounding air into the unit. Inside, desiccant material sits on a section of a wheel which rotates slowly. The fan draws the air over the desiccant material which absorbs the moisture. As the wheel continues to rotate the desiccant is then passed through a “regeneration” zone where the desiccant is warmed, expelling the water which collects in the tank. Nice and simple.
Most explanations for compressor units start out by saying “it works like a fridge” which doesn’t help unless you know how a fridge works!
Compressor dehumidifiers work by compressing a refrigerant gas (usually Freon) and forcing it through a condenser. This process cools the gas changing it to a liquid state. This liquid is then forced through a small valve into an evaporator unit. The pressure inside the evaporator is lower which allows the refrigerant to revert to a gas, losing heat in the process (known as an exothermic reaction).
In the mean time, a fan draws the surrounding air into the unit and passes it over the evaporator unit. This chills the air forcing the moisture to condense on to the evaporator surface. Think of a kitchen window whilst sprouts boil on the stove. Windows mist up – this is because the warm moist air comes into contact with a colder surface, chilling the air and causing the moisture to condense out of the vapour and collect on the window. In the kitchen scenario the water then runs down the window, but in a compressor dehumidifier the water is collected and piped to the tank. The cold, dry air then passes over the condenser coil which is warm, so heating the air again before passing it out of the unit and back into the room.
So which unit is best for you? Well, it depends what you need it for. For an unheated garage or storage unit then the desiccant is, without a doubt the most efficient and the most cost efficient option. This is because they operate without loss of efficiency at lower relative humidity and in temperatures as low as 1 degree Celsius.
Compressor units require warmer temperatures and higher relative humidity to function effectively otherwise the evaporator plates freeze, preventing them from extracting moisture from the air. Some of the more sophisticated compressor dehumidifiers, such as the Mitsubishi Electric MJ range, have a Hot Gas Defrost feature to combat this, but even so, in unheated storage areas the desiccants are a much better idea. For this application we would therefore recommend the Meaco DD8L Junior. Following this logic through we would also recommend it for inside boats, caravans and motorhomes whilst they’re in storage too.
So where would you use the compressor dehumidifier? In the home, where temperatures are generally higher and cooking, tumble drying, drying washing on a clothes horse or radiator, bathing, showering and even breathing – all producing higher levels of relative humidity, then a compressor unit can be the more cost effective option. However, the Meaco DD8L desiccant (the DD8L Junior’s big brother) has an anti-bacterial silver nano filter. As this makes the air healthier to breathe, it may be the preferred option for in-home use where there is an increased likelihood of allergies caused by dust mites. This could also make it the preferred choice for boat, caravan and motorhome owners.
If you are storing your car (motorcycle, boat, caravan or motorhome) this winter, the Meaco DD8L or DD8L Junior desiccant dehumidifiers are the best options. We use it – we think you should too.
Available as of the middle of November is the Meaco Mini-D Rechargeable Dehumidifier – a small, desiccant dehumidifier which doesn’t need permanent connection to mains power and is perfect for keeping the inside of cars, or storage spaces in boats or caravans free from damp.