Pull back the windscreen cover on a cold morning and find the glass dripping wet? You are certainly not the only one.
A campervan is a small space, and we put quite a lot of moisture into it. We breathe all night, boil kettles, cook food, hang damp coats up and occasionally come back from a walk looking as though we have fallen in a river. When that warm, moist air reaches a cold window or metal surface, the water condenses out of it.
So the answer is not one magic product. You need to reduce the moisture you can avoid, let damp air escape and stop the coldest surfaces getting quite so cold where practical.
Then, if you still get wet windows in the morning, get that water out of the van rather than moving it around with a cloth.
Why does a campervan get so much condensation?
Cold glass is usually where you notice the problem first, because it is one of the coldest surfaces in the van. The windscreen can be particularly bad because there is a large area of glass at the front of the vehicle.
But the glass is really just showing you what is happening. If the air inside contains plenty of moisture and a surface is cold enough, condensation can form there.
That is why completely sealing the campervan up on a cold night is usually the wrong approach. It may feel warmer for a while, but all the moisture you produce is still trapped inside.
Is it normal condensation or have you got a damp problem?
If two people have slept in the van on a cold night and the windscreen is wet in the morning, that is ordinary condensation.
If the campervan has been standing empty for days and you repeatedly return to wet windows, musty smells or damp furnishings, I would investigate further. There may be water getting in through a seal, rooflight, door, window, plumbing system or somewhere less obvious.
A moisture absorber might hide some of the symptoms, but it will not repair a leak.
Ventilation is the first thing to get right
You do not need a gale blowing through the van. You need somewhere for damp air to leave and somewhere else for replacement air to enter.
That might simply mean leaving a rooflight on its ventilation setting and cracking another window slightly. If you have a powered roof fan, it can actively pull moist air out while fresh air enters elsewhere.
Our campervan roof fans and ventilation guide explains that airflow in more detail.
It can feel strange deliberately opening a vent when it is cold outside, but a little controlled ventilation is usually far nicer than waking up to water running down the windows.
Cooking puts a lot of moisture into the van
Boiling pasta, making tea and simmering a pan all release water vapour. Cooking with an unflued gas hob adds more moisture from the combustion itself as well.
Use the roof vent or extractor while cooking and leave it running or open for a little while afterwards. If the weather is reasonable, opening a window on the other side of the van will help create a through-flow.
Our cooking in a campervan guide covers the main cooking options in more detail.
Wet clothing is much the same story. If possible, dry wet coats, towels and boots outside the living space rather than hanging everything inside and then wondering where all the water came from.
Does heating stop condensation?
Heating can help because warmer surfaces are less likely to collect condensation, but the type of heater matters.
A properly flued diesel or gas heater sends its combustion gases outside, so it can warm the van without adding that combustion moisture to the living space. A portable unflued bottled-gas heater does the opposite: burning LPG releases water vapour straight into the van, which can make a condensation problem worse.
Even with a flued heater, heat does not make the moisture from breathing, cooking and wet clothing disappear. Heating works best alongside sensible ventilation so damp air can actually leave.
For cold-weather touring, see our using your campervan or motorhome in winter guide as well.
External thermal screens can make a big difference
The cab is often the worst condensation area because the windscreen and side glass get very cold.
An external thermal screen puts the insulation on the cold side of the glass, helping the inside surface of the windscreen stay warmer. That is why external screens can reduce condensation far more effectively than simply putting a reflective blind on the inside after the glass has already become cold.
They also help retain heat in winter. The catch is that fit matters, so I would buy one made for the exact van cab rather than trying to recommend one universal screen for everything from a Transit to a Boxer.
If the windows are wet, remove the water from the van
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Even with good ventilation, you may still get some condensation on a cold morning.
A squeegee and an absorbent cloth work, but remember what happens to the cloth afterwards. If you wring it out and leave it hanging inside the campervan, much of that water can simply evaporate back into the same air you were trying to dry.
A small cordless window vac is useful because it collects the water in a tank. Empty it outside and the moisture has genuinely left the van.
A current example is the Kärcher WV 1 Cordless Window Vac. It is not a cure for condensation; it is simply a quick way of dealing with the water that still forms.
What about a dehumidifier?
A mains dehumidifier can be useful for storage, but choose it for the temperature where the van is actually kept. Compressor dehumidifiers become less effective as the air gets cold; for an unheated van that regularly drops below about 10°C, a desiccant dehumidifier is generally the more suitable type. It will usually use more electricity, but it continues extracting moisture at temperatures where many compressor units struggle.
If you use an active dehumidifier for storage, the idea is to let it control the air inside the van rather than leaving windows and roof vents wide open so that it spends its time trying to dry the outside air as well. Background ventilation and powered dehumidification are two different storage approaches, not things that automatically work better together.
A mains unit is much less attractive as an off-grid touring solution because of the electrical demand and the space it takes up. I would also be cautious about expecting tiny USB or low-power “mini dehumidifiers” to solve heavy overnight condensation in an occupied campervan. Two sleeping adults can add moisture far faster than a very small unit can remove it.
For storage without electric hook-up, a passive moisture absorber can still be useful for background humidity and musty smells.
The UniBond AERO 360° Moisture Absorber uses a replaceable moisture-absorbing tablet and needs no electricity. I would see it as a storage aid rather than the answer to two people sleeping and cooking in the van.
Condensation while the campervan is in storage
An empty stored van is a different problem from a van with people sleeping in it.
Start by removing obvious moisture sources. Do not leave damp towels, bedding or clothing inside. Make sure the water system is properly prepared for winter and give air a chance to circulate around cushions and cupboards rather than packing everything tightly together.
Our preparing your campervan for winter guide covers the broader winter-storage jobs.
If the van has mains power available and you want active humidity control, choose a dehumidifier suited to the storage temperature and keep the van reasonably closed while it is running. If you are not actively dehumidifying, background ventilation and a passive absorber are simpler options.
But if an unused van is repeatedly becoming very wet, find out where that moisture is coming from. No dehumidifier should be used to disguise a leaking rooflight or failed window seal.
A simple overnight routine
You can make a big difference without turning campervanning into a science experiment:
- keep some ventilation open while sleeping;
- use extraction or a roof vent while cooking;
- avoid drying very wet clothing inside if you have another option;
- use an external cab screen in cold weather if one suits your van;
- wipe or vacuum away morning condensation and take that water outside;
- give the van a good airing when the weather allows.
That is really the whole principle: make less moisture where you can, let the rest escape, and remove any water that still condenses.
Can you stop campervan condensation completely?
Probably not in every set of conditions, and chasing a completely dry windscreen after a cold night can be the wrong target anyway.
A little condensation on very cold glass does not mean the van has failed. The aim is to stop moisture building up day after day, soaking furnishings or collecting unseen in places where you do not want it.
Get the ventilation right first. Keep the cab glass warmer with a good external screen when it is very cold. Remove any water that does form. And if the van is wet when nobody has been using it, investigate the reason rather than accepting it as normal.