Boat dehumidifiers: A buying guide

Boats are naturally prone to damp, which can result in mould, mildew, musty odours, and even damage to woodwork, upholstery, and electronics. This is why a reliable boat dehumidifier is an essential item for any boat owner.

From compact desiccant boat dehumidifiers that work in cool, unheated cabins to compressor units suited to warmer conditions, there’s a wide range of options designed to suit different requirements. Here, we discuss the various types of boat dehumidifiers and how they work and detail some practical tips for choosing the right unit for your boat.

What is a boat dehumidifier?

A boat dehumidifier is a piece of equipment used on boats to remove excess moisture from the air. They can be used in cabins, storage areas, and other enclosed spaces prone to dampness. A decent boat dehumidifier will help to eliminate mould, mildew, odours, and condensation. 

When damp is left to worsen on a boat over time, it can lead to corrosion of metal parts and electronics and cause damage to wood, furniture, and fabrics. This makes a dehumidifier a vital item for any vessel.

How does a boat dehumidifier work?

There are a few different types of boat dehumidifiers to choose from. They all perform the same function, but each one works differently.

1. Compressor dehumidifiers

Electric boat dehumidifiers are similar to those that people use in their homes. They work by pulling moist air over cold coils and condensing the resulting water into a tank or through a drain hose. After moisture is removed, the air passes over warm coils and is sent back into the boat slightly warmer and much less humid.

2. Desiccant dehumidifiers

Desiccant boat dehumidifiers remove moisture from the air using a dry, moisture-absorbing material, like silica gel, rather than refrigeration. This makes them especially useful on boats, where temperatures are often cool and power may be limited. Desiccant humidifiers also tend to be more compact and quieter than compressors, so they make sense for smaller boats. 

3. Passive moisture absorbers

Passive moisture absorbers utilise crystals or salts to naturally draw moisture out of the air without requiring electricity. They’re low-cost, low-maintenance, and are ideal for use in lockers and storage compartments, small cabins, engine rooms where powered units aren’t practical, and on boats stored without shore power. 

6 of the best boat dehumidifiers

1. Meaco DD8L Junior Desiccant Dehumidifier

The Meaco DD8L Junior Desiccant Dehumidifier is one of the best boat dehumidifiers thanks to its marine-friendly performance and compact size. It successfully pulls moisture from the air in cool temperatures down to around 1°C, making it ideal for unheated cabins and winter moorings. With low running costs from just 8p per hour and a three-year warranty, it’s a reliable boat dehumidifier that’s affordable to run.

This boat dehumidifier can remove up to eight litres of water per day and works effectively in humidity levels typically found along UK waterways. The Meaco DD8L Junior Desiccant Dehumidifier is lightweight and relatively quiet, making it a practical option for most boats. It also has a range of handy features, including a built-in humidistat and continuous drain capability.

Buy the Meaco DD8L Junior Desiccant Dehumidifier

2. Seago Eco Dry

The Seago Eco Dry is a desiccant boat dehumidifier designed to work in the cool, damp conditions often found on boats in the UK. This dehumidifier boasts a maximum extraction of around seven litres per day, is very quiet when running, and is efficient in a temperature range between 1°C and 40°C. It’s a great option if you want to use your boat throughout the year. 

It features a digital display with adjustable backlight, auto-restart after power cuts, and both a removable two litre water bucket and a continuous drain option with a hose included. This boat dehumidifier is compact, lightweight, and has carry handles, plus there’s a sleep mode for when you’d like it to be extra quiet on board.

Buy the Seago Eco Dry

3. Waveline Portable Desiccant Dehumidifier

The Waveline Portable Desiccant Dehumidifier is a versatile boat dehumidifier that’s especially ideal for use in small to medium enclosed spaces like cabins and storage lockers. It has many great features, including a removable water tank and the option for continuous drainage via a hose. Plus a timer, adjustable airflow, and several drying modes, which can be used to tailor humidity control.

This boat dehumidifier works in temperatures from -5°C to 50°C, meaning it can be used effectively throughout the seasons. The Waveline Portable Desiccant Dehumidifier also has several safety features, such as auto shut-off, tip-over protection, and auto restart after power cuts, giving you peace of mind while on your boat.

Buy the Waveline Portable Desiccant Dehumidifier

4. EcoAir DC12 MK3

The EcoAir DC12 MK3 is a compressor boat dehumidifier, a reliable, budget-friendly option ideal for heated cabins and warm weather. This dehumidifier works in temperatures between 15°C and 35°C and has a maximum extraction of around 12 litres per day, with a 2-litre water tank and a continuous drain option. The EcoAir DC12 MK3 is quiet to run and features sleep mode, a 1-24-hour timer, and laundry mode for quick-drying clothes.

This boat dehumidifier is a practical choice that will tackle humidity in everyday boating conditions, especially when combined with ventilation and occasional heating.

Buy the EcoAir DC12 MK3

5 .Devola 12L Compressor Dehumidifier DV12L

The Devola 12L Compressor Dehumidifier DV12L is a great option for boat owners looking for a compact, efficient compressor dehumidifier that performs well and is easy to use. This boat dehumidifier can remove up to 12 litres of moisture per day and is ideal for use in small to medium cabin spaces. The unit runs very quietly, and it has an adjustable humidistat which means it will conveniently maintain your chosen humidity range without the need for constant adjustment.

With a continuous drain option, a reusable dust-proof filter, timer settings, castor wheels, sleep mode, laundry mode, and energy-efficient operation at about 5p per hour, the Devola 12L Compressor Dehumidifier DV12L is a practical, cost-effective choice.

Buy the Devola 12L Compressor Dehumidifier DV12L

6. DMD Collective 16L Compressor Dehumidifier

The DMD Collective 16L Compressor Dehumidifier is a great, affordable option if you’re looking to tackle condensation in warmer cabins or during the summer months. It can remove up to 12 litres of moisture per day under normal conditions, and up to an impressive 16 litres per day in very humid conditions. With a range of operating modes, including standard dehumidification, continuous dehumidification, and a laundry dry mode, you can tailor performance to your needs.

This boat dehumidifier has a 1.6 litre water tank with auto shut‑off and a continuous drainage option, adjustable fan speeds, quiet operation, and a compact, portable design which makes it easy to move between cabins or store when not in use.

Buy the DMD Collective 16L Compressor Dehumidifier

How to choose the right boat dehumidifier

Choosing the right boat dehumidifier can save you money, protect your boat’s interior, and keep cabins comfortable and mould‑free. Here’s what to consider when choosing the right one for your vessel. 

1. Temperature

Cold, unheated cabins are best suited to desiccant boat dehumidifiers as they work at lower temperatures than compressor options. For warmer spaces, like heated cabins, opt for a compressor dehumidifier as they’re often more energy‑efficient and remove moisture faster. However, keep in mind that their performance drops in cool conditions.

2. Capacity for the space

Dehumidifiers are rated in litres per day, and you should aim to purchase a unit that best suits the area you’ll be using it in. For example:

•    Small cabins and storage lockers – Five to eight litre desiccant or eight to 12 litre compressor
•    Medium cabins – Eight to 12 litre desiccant or 12 to 16 litre compressor
•    Large interiors – Consider higher‑capacity boat dehumidifiers or multiple units

3. Power availability

If you have access to shore power or a generator, you’ll be able to use a compressor or desiccant boat dehumidifier. If you have limited or no power, passive moisture absorbers or low‑power desiccant units might be better.

4. Continuous drain options

Emptying a water tank daily can be inconvenient, and a boat dehumidifier with a continuous drain outlet allows you to run a hose to a bilge pump or bucket, making it ideal for unattended use. Ensure the drain hose setup remains secure and dry to prevent spills.

5. Noise level

Quiet boat dehumidifier units are better for sleeping areas and compressor models are usually louder than desiccant ones, so check the decibel rating before making a purchase. Some units also come with a sleep mode which makes them run quieter and dims the display, so keep an eye out for this feature.

6. Marine appropriate features

Marine conditions are harsher than those in houses, so look for dehumidifiers with corrosion‑resistant components, washable or reusable air filters, auto‑restart after power loss, and auto‑defrost for compressors. Some units are created specifically for boats and often include anti‑corrosion coatings or are designed for damp environments.

7. Ease of maintenance

Choose a unit with removable filters that are easy to clean, an accessible water tank and tank sensor, simple controls, and clear indicators. Regular filter cleaning keeps efficiency high and mould at bay, so be sure to maintain your boat dehumidifier regularly.

8. Thermostat and humidity control

Boat dehumidifiers with a built‑in humidistat allow you to set a target humidity. This prevents over‑drying and saves energy which is especially useful if the boat is occupied.

9. Installation and placement

Place your boat dehumidifiers central to the space or close to the most humid area. Desiccant units are lighter and easier to reposition while compressor units are heavier and need more space.

10. Price vs value

Desiccant boat dehumidifiers cost more upfront but perform better in cold, damp conditions. Compressor units can be cheaper and efficient in warm environments but may struggle in winter. Be sure to consider running cost, expected lifespan, and climate when comparing prices.

Specialist boat insurance through Craftinsure

Before your next trip out on the water in your boat, you may want to consider getting specialist boat insurance.
Specialist boat insurance through Craftinsure can help provide financial protection against damage and the theft of your boat, equipment and outboard motors, as well as up to 30 days of European cover. Get a quick online quote.