Most dehumidifier reviews are written for houses and basements. A boat is a different problem: it rocks, it’s small, it’s often unattended for days, and it sits on water. These are the things we learned running dehumidifiers on boats that sit at the dock, plus the two units we use in the engine room, galley, and cabins. This applies most to coastal boats, but it’s useful on any boat that sits on the water.
What to Look For in a Boat Dehumidifier
- No wheels. Boats rock, and a wheeled unit wants to roll around or tip over. If you buy one with wheels, you’ll end up wedging it in place.
- A drain hose, not just a tank. If you leave the boat for any period of time, a tank fills up and shuts the unit off. A hose to a sink or drain lets it keep running.
- Humidity control. A unit you can set to a target humidity, instead of only running nonstop, works better on a boat you’re not aboard every day.
- 110V shore power. All of ours plug in, so this post is written for boats kept at a dock or marina.
- One unit per zone. We run three: engine room, galley, and cabins. Moisture builds up differently in each space.
Quick Comparison
| Dehumidifier | Price | Where We Use It | Wheels? | Drain Options |
|---|---|---|---|---|
| Ozeeco 34 Pint/Day | ~$123 | Engine room | Yes | Drain hose |
| Onsekin 2000 Sq.Ft | ~$109 | Galley and cabins | No | Hose or tank |
Ozeeco 34 Pint/Day Dehumidifier with Drain Hose: Strong Performance, but Skip the Wheels
Price: ~$123
Where we use it: Engine room
Listed specs: 34 pints/day, rated for up to 2,500 sq ft, 35 dB
This unit pulls a lot of water out of the air, which matters in an engine room where heat, moisture, and closed-in space combine to cause corrosion and mildew. It also has two operating modes. Continuous mode runs it nonstop, and
humidity-set point mode lets you pick a target percentage so it kicks on only when the air reaches that level. The setpoint mode is the more useful one for a boat you’re not aboard every day.
It comes with a drain hose, which is the feature that matters most on a boat. A tank fills up and shuts the unit off, but a hose lets it keep running while you’re away. We run ours into the bilge, so there’s no tank to empty and no trip aboard just to keep it going.
A safety note on bilge drains: Draining into the bilge means you’re adding water there continuously, so your bilge pump has to be in working order before you rely on this setup. Test the pump and its float switch, and confirm it’s set to run automatically, before you leave the boat unattended. A dehumidifier that fills a bilge with a dead pump creates the problem it was meant to prevent.
Downside: It has wheels, and on a boat that’s a problem. Boats rock, and a wheeled unit wants to roll around or tip over, so we had to wedge ours into a spot to keep it in place. It works fine once secured, but if you’re shopping for a boat, buy a model with no wheels.
Best for: Boat owners who want strong moisture removal, flexible humidity control, and a hose drain for unattended stretches, and who don’t mind securing it in place.
Onsekin 2000 Sq.Ft Small Dehumidifier with Drain Hose: Best for Galley and Cabins
Price: ~$109
Where we use it: Galley and cabins
Listed specs: rated for up to 2,000 sq ft, 3.3 ft drain hose, 2.5L tank, timer and sleep mode
This is the unit we run in the living spaces of the boat, and it meets the first rule of boat dehumidifiers: no wheels. Nothing to roll around or tip over when the boat rocks.
Its best feature is that it works two ways. With the drain hose attached, it runs unattended while you’re away. Put the small plug in the drain port instead, and it becomes a tank-style unit. When we’re aboard, we switch to tank mode, because you can set it down anywhere and just empty the tank whenever it suits you. When we leave, we go back to the hose.
Like the Ozeeco, it’s programmable. You can set a target humidity level and let it cycle on and off, or run it continuously.
A safety note on heat: Because it runs hot, give it breathing room. Leave space around the unit, keep it out of tiny closed-in spaces, and don’t run it shut in a small room while the boat is unattended. It’s sensible practice for any heat-producing appliance on a boat.
Downsides:
- The 3.3 ft hose is short, and you can’t stretch it. We tried running it farther than it wanted to go, the hose pulled out, and water ran across the bathroom floor. Now we run it into the sink, close to the unit, with the hose in a natural position. Plan where the unit sits around where the drain is, because the hose won’t make up the distance for you.
- It runs hotter than the Ozeeco. In a small bathroom with the door closed, it got noticeably hot.
- The LED light is useless. It serves no purpose we could find, and it’s one more light in a cabin where you’re trying to sleep.
Best for: Boat owners who need a no-wheels unit for the galley and cabins and want the flexibility to switch between hose drainage while away and tank use while aboard.
Which One Should You Buy?
- Galley or cabins, or you want the most flexibility: Onsekin. No wheels, and it works with the hose or as a tank.
- Engine room or another space that needs heavy moisture removal: Ozeeco. It pulls a lot of water, but you’ll need to secure it because of the wheels.
Whichever you choose, the same rules apply on a boat: no wheels if you can help it, a hose drain if you’ll be away, and a quick check of your bilge pump and your hose connections before you leave. A dehumidifier works best when it can run unattended without causing a problem of its own.