Don’t use a Dehumidifier in Your Motorhome before you READ THIS!

Wondering if it’s ok to use a dehumidifier in your motorhome, caravan or campervan? Worried about damp, mould, fire, cost or practicalities? After years of experience, here’s everything you need to know about using a dehumidifier when you’re not using the van.

*We work hard to make this the best motorhome travel blog and road trip website possible, full of helpful content for you. The website is supported by our readers, so if you buy through links on this site we may earn a commission- at no extra cost to you. All opinions remain our own.

If you find this post useful, you can also treat us to a coffee – we promise to enjoy it while creating more useful content like this- we might even indulge in a biscuit (or two!)

Using a dehumidifier in a motorhome or camper

Look on any forum or group, and you’ll see a discussion about the practicalities of using a dehumidifier in a camper, motorhome, RV or boat to remove moisture from the air.

Some people swear by them, others say they’re a waste of money. So which is it? If you’re going to leave your motorhome unused for a period of time (usually over winter), should you be using a dehumidifier?

Why Moisture is a Problem in Motorhomes

Motorhomes are AWFUL for moisture build up. The confined space and range of uses (kitchens, bathrooms, living areas, and sleeping) create the perfect environment for moisture to accumulate.

Just being in one for a day causes something like a litre of moisture to go into the air. Add to that wet coats, pets, limited ventilation and lots of hot drinks, and you can see how it quickly builds up- especially in Autumn and Winter.

Left unchecked, all this moisture can lead to a host of issues that affect both your comfort and the longevity of your motorhome, including:

• Condensation Buildup: Persistent condensation can lead to water pooling on surfaces like window ledges, which may seep into the structure of the motorhome (especially bad if you have any wood in the base structure.)
• Mould and Mildew: High humidity levels create an ideal breeding ground for mould and mildew, which can not only damage your motorhome’s interior but also pose health risks, particularly for those with allergies or respiratory conditions.
• Damp Smells: A musty odour is often one of the first signs of moisture problems, caused by damp fabrics, carpets, or hidden mould growth.
• Damage to Fixtures and Fittings: Over time, moisture can warp wooden fittings, corrode metal fixtures, and damage upholstery or insulation.
• Permanent Damage: Excess moisture can significantly reduce the lifespan of your van’s interior and lead to costly repairs. For full-time vanlifers or those touring in cooler seasons, addressing moisture is crucial to ensure a dry, healthy living environment.

How to monitor the humidity levels in your camper

If you are unsure of the humidity level in your van and don’t have an inbuilt monitoring system, you could add one of these humidity monitors to your motorhome or campervan:

If you’re leaving the van in storage for winter and aren’t there all the time, you’ll probably prefer something like the last one, which has an app and alerts for monitoring the vehicle when you’re not there.

The Problems with Dehumidifiers

So, we know we don’t want a lot of moisture in the vehicle. Surely a dehumidifier is the perfect solution- yes?

Well… maybe. But it’s not that straight forward.

Dehumidifiers work by removing moisture (humidity) from the air, stopping that moist air leading to problems like mould and condensation in your motorhome.

They work to remove any excess moisture until it’s in an optimal range (usually 40-60% humidity).

The trouble is, most motorhomes and campers aren’t fully sealed. They have (deliberately) air holes to allow gas to escape. There are also often tiny gaps around door frames and window frames (deliberately or caused by many miles of driving over bumpy roads!)

All of which means- the dehumidifier is rarely satisfied. As more (damp) air enters the van, it keeps working and working… and working.

This can lead to problems such as large electrical drain, burnout and, in the most extreme cases, fire.

But that doesn’t mean they’re not worthwhile. In fact, there are some I highly recommend. Read on…

Fulltime Vanlife vs Storage

Many people who live full-time in their motorhome or camper have no need of a powered dehumidifer, as they are constantly in the vehicle to give ventilation and heating. For that reason, if you’re in your van a lot throughout the year, I recommend something like these Moisture Absorbers – a friend of mine who lives full-time in her van swears by these.

HOWEVER… if you’re winterising your motorhome (putting it away for the winter), you need to do one of these three things:

Dehumidifiers Vs Heaters Vs Ventilation

As mentioned above, there are a couple of other ways to deal with the winter damp and cold. Heating and Ventilation.

A dehumidifier actively removes moisture from the air, tackling condensation and reducing the risk of dampness and mould. However, it doesn’t address the root cause of moisture. It might warm the air slightly, but not enough for cold air to become warm.

Heating raises the temperature inside the motorhome, which can help reduce condensation by warming cold surfaces, but on its own, it doesn’t remove humidity from the air.

Ventilation allows moist air to escape and fresh air to circulate, preventing humidity from building up in the first place. While ventilation is essential for reducing overall moisture levels, it can be less effective in cold or rainy weather when keeping windows or vents open isn’t practical.

The best option is to combine these methods. which is just one of the reasons you should check on your vehicle regularly and maintain it when you’re not using it.

How Do Motorhome Dehumidifiers Work?

For the purpose of motorhome, caravans and campers – there are two types of dehumidifiers that we’ll look at:

• Compressor Dehumidifiers
• Desiccant Dehumidifiers (I’ve also added in portable dehumidifiers, as they work the same way for our purposes)

Compressor Dehumidifiers

Compressor or Refrigerant dehumidifiers work by drawing in moist air using a fan. This air then comes into contact with cooled coils, the water in the air condenses and drops down into a water reservoir, while the (now dry) air passes through the warm coils and heats back up, before being released back into the surrounding environment.

Because these use cooling and heating methods, these dehumidifiers usually require mains power to work. They also require you to empty the water tank regularly or they stop working.

I’ve used a compressor dehumidifer for years in my bathroom and it’s brilliant (especially for bathrooms without windows). It’s also great for motorhomes which are kept somewhere with a mains power source and can be monitored (like on a driveway)

• How They Work: These use a compressor and refrigerant to cool a coil, causing moisture in the air to condense.
• Best For: Warm or moderately cool environments.
• Advantages: Energy-efficient and powerful in higher temperatures.
• Drawbacks: Less effective in colder conditions, as they rely on warm air to function efficiently. Need mains power. Need to be emptied regularly. Shouldn’t be left on for hours unattended.

Desiccant Dehumidifiers & Portable Dehumidifiers

Desiccant models work using water-absorbing material to collect moisture. They usually consist of absorbent materials like gels, silica beads, or salts. Humid air is drawn over the material and as the air cools moisture is collected.

Once the absorbent material is full you will need to either replace or recharge the pouches or replace the entire dehumidifier device.

Because these dehumidifiers use a material already in place, they often don’t need any power source at all. These are perfect for motorhomes or caravans which are in storage over winter. The powered versions are better in larger spaces, but are often noisy.

• How They Work: These use a chemical desiccant to absorb moisture from the air.
• Best For: Cold climates, off-grid or winter motorhoming, small spaces like wardrobes
• Advantages: Operates efficiently in low temperatures, quieter than compressors. Most don’t require power
• Drawbacks: Powered versions use more energy compared to compressor models. Need changing regularly to be effective. Not good for large spaces.

Which Dehumidifier to choose?

So, which type is best if you’re not using your vehicle throughout winter? Here are some questions to help you choose:

• Do you store your vehicle at home or very near by so you can check it daily/ regularly?
• Do you have 230v power while your van is in storage or on the driveway?
• Will you be able to get to the van to empty a full container?

If the answers to these are all yes, then I recommend a compressor dehumidifier alternated with a heater like an oil-filled radiator. Leave the heater on, and once or twice a week, run the dehumidifier.

If the answers to one or all are no, go for several non-powered dessicant dehumidifiers. Ideally, visit the vehicle at least once a week to put the heating on, air it out and prevent large levels of moisture building up. (The humidity monitor can really help with your peace of mind.)

Final Thoughts

A dehumidifier can be a valuable tool in managing moisture in your camper. However, it’s not a standalone solution. Combining a dehumidifier with proper ventilation and heating ensures the best results for keeping moisture under control.

If you’re still unsure, start by monitoring your motorhome’s humidity levels with a hygrometer and assessing the moisture issues you face. With a little trial and error, you’ll find the perfect balance to keep your motorhome dry and cosy on every adventure. Let us know in the comments how you manage moisture in your motorhome—your tips could help others!

Last update on 2024-11-20 / Affiliate links / Images from Amazon Product Advertising API

Sharing is caring!