Damp, condensation and in particular, mildew drives me to instant apoplexy! If there's one piece of advice I can give to any boat owner is GET YOURSELF A GOOD DEHUMIDIFIER! Here's my top choices currently available.
It sounds obvious, but boats tend to live in a damp environment. Even if you keep yours ashore or in your driveway, damp can still be an expensive problem. A good, reliable dehumidifier is an absolute essential piece of kit for pretty much every boat owner that has a boat with enclosed living space. I own two dehumidifiers and both work flat out from late autumn to mid spring here in the UK and in the Azores where humidity is often around 95%.
It doesn’t matter if you live on your boat or not, moisture, even in a boat laid up for winter can be a really expensive and damaging problem.
An added challenge with boats is that that salt water inevitably finds its way down below. And salt, as we all know, retains moisture.
Since iron will start to rust when the relative humidity exceeds 50% (80% for steel), the problems caused by damp aren’t limited to mould, mildew and mustiness: electronics, electrics and engines will suffer too, not to mention tools.
If you don’t already have a dehumidifier, then what are you waiting for? These things pay for themselves in the reduction of damp induced electrical gremlins and mildewy interiors.
At a glance, Editors top three choices
Meaco DD8L Junior – Best Desiccant lightweight model – Buy it now
Ufesa 10L dehumidifier – Best compact compressor model – Buy it now
Ecor Pro DH1200 Inox Dryboat – Best premium integrated model – Buy it now
11 of the best boat dehumidifiers available right now
Reasons to Buy
Quiet, extracts lots of water, lightweight, has worked faultlessly for years
Reasons to Avoid
uses a little more power than a compressor type, filter housing is a little fiddly.
Meaco DD8L Junior. Made in the UK, this desiccant model from Meaco has proved very popular among boat owners because of its light weight (6kg/13lb), low noise and efficiency at low temperatures.
Fox Morgan, the Tech Editor here at Yachting Monthly notes: Indeed it was a recommendation from a fellow boat owner that made me run off to the internet to find one for my own boat about 8 years ago.
They claim it can extract 7.5 litres of water per day at 20°C and 60% relative humidity. It has two fan speeds, a variable humidistat and a laundry mode for maximum extraction or for drying clothes. I can’t say exactly how much this fabulous little Meaco Junior actually extracts, but if I put it on the laundry dry setting over night, it empties the dogs water bowl nearby. It’s really very efficient at sucking water out of everything nearby. The benefit of the desiccant dehumidifier is that it blows gently warmed air out of the top, so it keeps the air moving in the boat as well as adding a bit of warmth.
It comes with a tube to allow continuous draining, but the unit is too tall to fit on any of my boat counters, so I’ve been unable to use that function on my boat.
It’s economical to run because of the way it has an air sampling setting, so when it’s reached the level of dry you want, it just ticks over, clicking in to sample and then back off again. When running on the second fan setting it consumes roughly 700W constant.
This unit, pictured has been used for at least 6 months of every year for the past 8 years, mostly on my boat, but occasionally in a camper van and a damp office. It’s been faultless and it has been a brilliant bit of kit that has easily paid itself several times over in reducing mildew damage to zero. Its been a total game changer for stress free winter boat maintenance.
5 stars from me for this stalwart bit of kit.
If you want an ioniser and an anti-bacterial filter, you can spend a little more and buy the DD8L model as opposed to the DD8L Junior.
Reasons to Buy
compact size, easy to access and clean filter, efficient and simple operation
Reasons to Avoid
noticeable hum, caster wheels are both a blessing and curse
A compact and lightweight model, the Ufesa will fit into smaller spaces and fit easily on countertops.
The supplied tube will allow you to leave this unit draining into a sink or other drain. This compressor unit is fairly quiet, but in a small space you will hear it working.
It’s efficiency is on par with most other compressor dehumidifiers and after a day switched on, the humidity is noticeably reduced. It doesn’t have the sophistication of some more expensive models, but it gets the job done. It does have a laundry setting too which basically makes the unit work flat out, but it has dried stuff pretty well when laundered and hung to dry nearby.
This unit has been on test for 2 years in a high humidity environment in a boat based in the Azores Islands in mid Atlantic and has performed well. Though it would struggle if the ambient temperature were to drop below 5c, so an additional heater might be required if this is used in a cooler climate. Otherwise, as with all compressor dehumidifiers, you’ll lose some efficiency due to defrost mode.
The little caster wheels are both a blessing and curse. To keep this safe on the counter top, I’ve had to jack it up onto some books to stop it rolling around when the boat rocks during inclement weather on its berth.
This is one of the lightest, simplest and least expensive desiccant dehumidifiers on the market. Despite its relatively low price, it does a lot more than the old basic ‘on/off’ compressor types that some of us have been using for years.
One useful feature is a humidity dial, which allows you to set the level at which it turns itself off to save power. When power-saving is less important than drying a particularly damp space or directing the heat to help dry clothes, you can leave it on the ‘laundry’ setting for short periods. There’s also a two-speed fan, and a nano-silver anti-bacterial filter to help clean the air.
Weighing a modest 6kg (13lb), the DD1 Simple has a carrying handle on the top and is claimed to extract 7 litres of water a day at 20°C and 60% relative humidity.
Price: from £155
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Some manufacturers have traditionally concentrated on compressor dehumidifiers, which have a reputation for lasting longer than desiccant types as well as for using less power. This means that people tend to be happier to leave them on for longer, while the nature of their noise is often considered to be less intrusive even if the actual decibel count is no lower.
De Longhi’s DEX214F sit in the middle of their range, with an extraction rating of 14 litres of water per day (given the standard test conditions of 30°C and 80% relative humidity, which are rarely seen on a boat in a high-latitude winter).
Buyers with environmental concerns about refrigerant gases will be reassured to know that DeLonghi use R290 gas, which is claimed to be much more environmentally friendly than the gases traditionally used in refrigeration appliances.
Price: from £217
Mitsubishi MJE 16V
This is by no means a budget dehumidifier, but that’s not what Mitsubishi designed it to be. Although it uses a compressor rather than desiccant, it has a low-temperature function that’s said to keep it working efficiently in cold weather.
Compressor dehumidifiers have to stop working at intervals when the temperature drops and moisture freezes on the cold plates of the heat exchanger, but the Mitsubishi has a hot-gas defrosting system to help offset this generic drawback.
In warmer, humid conditions (the standard 30°C and 80% humidity at which dehumidifiers are rated) it has a capacity of 16l per day.
A variable humidistat is among the other features, together with a laundry function, on/off timer and deodorising filter.
Price: from £330
Ecor Pro DH1200 Inox Dryboat
If you want a seriously heavy-duty dehumidifier that’s made of stainless steel to withstand the marine environment and that can be left unattended and running 24 hours a day, one of the Ecor Pro desiccant models is likely to attract your attention.
Designed in the UK, the DH1200 Inox will extract up to 12l per day and can be free-standing or attached to a horizontal surface or a bulkhead. It has no water bucket because the moisture is vented out through a duct that will accept standard 41mm waste pipe. You can also attach an inlet pipe to suck in moist air from elsewhere.
Operating temperatures range from -20 to +40°C and this boat dehumidifier has been engineered for ease of access when maintenance is needed.
Price: from £630
Seago’s Ecodry is one of the small number of dehumidifiers to be designed with boat owners very much in mind. You should be able to leave it running continually and, being of the desiccant type, it will keep working (collecting up to 7l a day) at temperatures down to 1°C.
Features include a digital display on the top, where you set the mode (choices include ‘sleep’ for lower noise and a dimmed display) and where the temperature and humidity are shown.
Carrying handles are recessed into the sides. While that’s arguably neater than having a fold-down handle on the top, you won’t be able to attach a line to haul it up if you’re on deck with the boat ashore. Then again, being one of the lighter and more compact boat dehumidifiers (it weighs 6kg/13lb and is less than 500mm/20in high), it’s less of a lump than some to carry up a ladder.
Price: from £179 / $250
Ebac is a British manufacturer with a different take on what a dehumidifier needs to do and the best way to do it.
Rather than trumpeting the benefits of desiccant dehumidifiers and humidistats that allow you to choose the humidity level you want, Ebac presents an argument in favour of the compressor combined with their own patented Smart Control feature.
Compressors are used for their appreciably lower running costs – up to 40% lower, it’s claimed – while the Smart Control is said to detect changes in temperature and moisture levels, switching the dehumidifier on and off as needed.
Ebac’s premise is that there is no consistently ‘right’ level of humidity for any given environment: it varies continually, and the 3850e responds by extracting only as much moisture as is needed to avoid damp and condensation rather than making the space unnecessarily dry and sucking in more damp from outside.
It also incorporates a defrosting system that minimises the time when it’s out of action.
Meaco DD8L Zambezi
PBO tested: Meaco DD8L Zambezi review
If you like the Meaco approach but want something with a few more bells and whistles than the basic DD8L models, the Zambezi (named after an orphaned elephant in Zambia) might be the answer.
It’s a desiccant machine with a maximum extraction of 8.3l per day (at 20°C) and should still extract 7.5l at 10° and 60% humidity. Power consumption at 20° is 351W and the tank capacity is a larger-than-average 3l.
Features that make it more expensive than Meaco’s other models include the sterilising ioniser and a low-energy laundry setting. It also has full timing functions, which allow you to set when it comes on and when it goes off.
EcoAir DD3 Classic Mk II
Like most manufacturers, EcoAir offers models to suit a range of budgets and the Mk II version of their popular DD3 Classic dehumidifier comes with more features than you find on the lower-priced alternatives. As well as auto-restart after a power interruption and a laundry mode – both widely found elsewhere – this one incorporates multiple timer settings and an antibacterial nano-silver filter. It’s said to be quieter than its predecessor, producing 36dB on its lower setting.
Being a larger unit, with an extraction rate of up to 10.5l per day, it uses a little more power: consumption ranges from 420-735W. With a capacity of 4.2l, the tank is bigger too. It’s 520mm (20in) high and weighs 7.5kg (16.5lb).
Pro Breeze 10L
ProBreeze makes both desiccant and compressor dehumidifiers as well as smaller models that use Peltier (thermo-electric) technology to create a cold plate on which moisture condenses.
If you heat your boat in the winter, you might find that a compressor dehumidifier makes most sense; otherwise opinions in colder climes tend to shift in favour of desiccant types and ProBreeze’s 10L (which stands for 10l of extraction per day) is the company’s offering in this department.
It offers a humidity sensor so you can set your chosen level, a digital control panel, a timer, a fold-down handle on the top, an adjustable outlet for the warm air, a nano-silver filter and a 3l collection tank.
What makes the best boat dehumidifier?
Mechanical dehumidifiers that run from a mains supply are often left on the galley worktop to drain into the sink so they don’t cut out when the water bucket fills up. That’s unless you have a top-of-the range boat dehumidifier that’s ‘plumbed in’ and expels water to the outside.
Your first choice is likely to be whether to buy a condenser type of boat dehumidifier or one of the newer desiccant types. The former use a compressor and refrigerant gas to create cold plates or coils on which moisture in the air, drawn in by a fan, condenses before dripping into a bucket.
With the desiccant dehumidifiers, the air passes over a rotating wheel coated with an absorbent material (typically zeolite). The saturated wheel is dried by hot air that’s then cooled so, again, the condensed moisture is collected. This process is more power-hungry, but desiccant dehumidifiers are typically lighter. They also heat the surrounding air and work better at lower temperatures, when condenser types have to shut down periodically to defrost.
Whichever you buy, bear in mind that not all domestic dehumidifiers are designed to be left running for lengthy periods. There have been instances of fires on board being attributed to boat dehumidifiers, so it’s a good idea to check with your insurers just to make sure.
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