Which Dehumidifier for a Boat?

For us, a good marine dehumidifier is an essential part of being commuter cruisers.  We have never returned to the boat to find mold or mildew – and have our JBP DryAir, Model DH-5 stainless steel dehumidifier to thank.  There are several considerations when shopping for a dehumidifier for your boat, these were ours:

1.  Continuous Draining.  Most “home” dehumidifiers drain into a “bucket”, which is a problem if we’re gone for six months.  No one is available to drain the bucket daily.  While the price tag seemed attractive, we couldn’t figure out how to jerry-rig a home model to continuously drain , preferably into our galley sink.  We could also have it drain into the bilge, but if the bilge pump failed we might have a problem.  The galley sink automatically drains overboard without including the bilge pump in the loop.

2.  Electricity.  Energy efficiency is a consideration, but not the primary consideration when choosing a dehumidifier unit for your boat.  Energy efficiency is one of the reasons we choose to have both a room air conditioner and a dehumidifier – the a/c unit consumes MUCH more electricity and therefore would be much more expensive to leave running all the time for six months while we’re gone.  The dehumidifier just sips electricity – someplace online said it consumes as much electricity as a light bulb, but all I know is that our electricity bill is extremely low.

3.  Power Outage.  The most important reason to have a marine dehumidifier is it does not have to be reset after the power blips – which it does several times a day or week in locations such as the Rio Dulce, Guatemala and Bocas Del Toro, Panama.  When the power goes out, obviously the unit shuts off.  But the minute the power comes back ON, our dehumidifier comes right back on – it purrs like a kitty while removing all the excess humidity from the air inside the boat!  Regular dehumidifiers have some type of electronics that means they do NOT turn back on automatically after a power blip.  Several cruisers have attempted to buy our dehumidifier after discovering this nuance of commuter cruising.

4.  Construction.  A good boat dehumidifier will have a low center of gravity, be relatively lightweight and have no castors to roll around.  Typical home dehumidifiers are tall and narrow and could tip with the motion of a boat, even in a slip.

5.  Stainless Steel.  Humidity and salt air cause everything to rust.  Our stainless dehumidifier just keeps on purring and removing water day in and day out (knock on teak!).  Our condensation tubes are copper.

6.  Carry Handle.  Most dehumidifiers are bulky and even the “lightweight” ones are heavy.  Having a carry handle makes it easier to transfer to storage under the pullman berth each year when we return to the boat and get it out of storage when the season’s over.

7.  Reliability.  Given the fact that our stainless dehumidifier cost almost twice what a household unit would have been, it would be nice if it would last a LONG time!  So far, so good.  This is it’s 10th season and our current caretaker reports it’s still purring right along.

So why spend the money for a dehumifier at all?  Won’t dessicant products such as Damp Rid do the job?  Yes, but they fill up very quickly in such a humid atmosphere and need replaced regularly.  If your caretaker is willing to replace them regularly, you might be able to get by with these products, or even raw charcoal as some advocate — we never were willing to try that approach because charcoal is combustible and we didn’t want to add anything to the boat that might blow up or start a fire.

IMPORTANT Dehumidifier Tip:   All dehumidifiers allow you to set the percent of humidity left in the boat.  We never set ours below 60% because too little humidity can dry out all our solid teak staved paneling and woodwork below.  One year a caretaker set it a bit lower than what we left it as and the lid on our nav desk warped and cracked.    Aaaarrrgggg!!!

Also, it’s important to think through your ventilation plan while you’re away from the boat.  We have a solar powered fan installed on one of our dorades which sucks air out of the boat and other dorades that allow air in, plus the dehumidifier has a fan to circulate air.  So the inside air is constantly circulating, not stagnant, which is another big factor in keeping mold and mildew out.

Do you have other solutions, or know of a place you can buy a dehumidifier similar to ours?   We bought it so long ago and I cannot find an online source that sells them.  Please leave a comment and let us all know!  THX!  Jan