Motorhome condensation happens when warm, moist air inside your van meets cold windows or walls, turning into water droplets. It’s common but can lead to mould, damp, and structural damage if ignored. You can prevent it by improving ventilation, using thermal screens, and reducing indoor moisture.
Motorhome Condensation: Why It Happens, What Damage It Does, and How to Stop It
Condensation is nothing new to any of us. We’ve all wiped it from windows at home, or drawn stick men and smiley faces in it. However, in a motorhome it can quickly become a serious nuisance.
Left unchecked, it can even cause structural damage. When conditions are right, many first-time owners wake up feeling a little damp and are amazed to discover just how much moisture collects overnight; sometimes gallons of the stuff. Then, the first thing they do is put the kettle on… and add to it.
I’ve always been a paranoid about damp since I saw photos of what condensation did to a Hymer motorhome. For years, the owner allowed condensation to run unchecked down the inside of the windscreen and door windows into the engine bay and door frames. The subsequent rust and rot put the van beyond repair!
If you had a hole in the roof that lets 6 pints of water in every night. You would probably get it fixed quickly. When you are living in your motorhome, condensation can dump just as much water in your van.
Let’s look at what causes it, why it’s more than a nuisance, and how you can keep your van dry and comfortable all year round.
What Actually Causes Condensation in a Motorhome?
Condensation forms when warm, moist air meets a cold surface. Inside a motorhome, that means steam from cooking, showering, or even breathing hits cold windows or walls and turns back into water droplets.
We’ve been amazed at how much condensation can be caused overnight, with just the breathing of two humans and German Shepherd Dog!
Motorhomes are cosy but sealed spaces; great for keeping heat in, terrible for letting moisture out. The more warmth you create inside, the more that moisture wants somewhere to go, and if it can’t escape, it settles on your glass, walls, and cupboards.
Typical causes of condensation include:
- Cooking without ventilation — boiling the kettle or pasta with the windows closed.
- Sleeping with everything shut tight — two people breathing all night can create up to a litre of water.
- Drying clothes inside — quick, easy, and a fast track to a rainforest interior.
- Cold weather and poor insulation — chilly surfaces encourage condensation to form.
What Problems Does Condensation Cause in a Motorhome?
A bit of misted glass might seem harmless, but long-term condensation can lead to serious issues — and expensive repairs.
Here’s what can go wrong:
- Mould and mildew: Those dark patches in corners or behind cushions are a sign of trapped moisture. Mould spores love warm, damp air.
- Musty smells and soggy fabrics: Soft furnishings soak up moisture and never quite dry out again.
- Hidden damp and wood rot: Persistent moisture can creep into wall panels, window frames, or the floor, causing rot or delamination.
- Condensation streaks: Constant dripping down the inside of windows can stain or damage seals over time.
Think of condensation as a slow, invisible leak; ignore it for long enough, and it’ll cause the same kind of damage.
How Do You Stop Condensation in a Motorhome?
You can’t completely eliminate condensation, but you can control it. The trick is keeping your motorhome ventilated and warm enough that moisture has somewhere to escape.
1. Ventilate Every Day
Open a roof vent or window whenever possible. Even a small gap helps warm, moist air escape. Modern roof lights have a ‘just cracked’ setting that allows airflow without losing too much heat.
2. Use External Window Screens
Cab windows are condensation magnets in cold weather. External thermal covers create a barrier that keeps the glass warmer and drier overnight. Good external windscreen covers are the most effective defence you have against condensation. People try internal covers but almost all agree they are nowhere near as effective as external screens.
3. Avoid Drying Clothes Indoors
Tempting, but disastrous. Wet clothes release litres of moisture. Use the campsite laundry or, if you must, dry them in the bathroom with the vent open and the door closed.
4. Cook with Lids On and Windows Open
A simple but effective trick. Lids trap steam, and a bit of ventilation clears the rest. If you’ve got an extractor fan, use it. Better still, cook outside whenever you can.
5. Try a Dehumidifier or Moisture Traps
If you’re on hook-up, a small electric dehumidifier is brilliant overnight. Off-grid? Use moisture traps or refillable silica gel tubs instead. Just remember to empty or replace them regularly.
6. Insulate Cold Spots
If you notice condensation on certain walls or metal window frames, add insulation or reflective mats. Warmer surfaces attract less moisture.
We once had a motorhome with an over-cab bed, and for some reason, the front left corner was always a particularly cold spot. Warm, moist air from cooking and showering would drift up into the Luton and condense on that chilly corner, leaving the bedding damp.
At the time, we didn’t use that bed area, and only discovered the problem when we caught the unmistakable smell of mould growing under the mattress! Cracking open the cab bed’s skylight and closing the cab curtains while cooking or showering stopped the condensation straight away.
7. Take extra care when showering
Showering in your van is one of the biggest condensation culprits. A single hot shower can release a surprising amount of moisture into the air, and if it’s allowed to spread through the living area, it’ll soon find the coldest surfaces to cling to. If you’ve got an extractor fan, make sure it’s running before, during, and after your shower. Try to keep all the steam contained in the bathroom by keeping the door shut. Once you’re done, ventilate thoroughly, open a window or roof vent to let the damp air escape before it has a chance to settle elsewhere.
8. Wipe Down Every Morning
Even with good prevention, you’ll still get a bit of moisture. Keep a microfibre cloth handy to wipe windows and skylights. It only takes a minute but prevents long-term damp.
Condensations runs downhill, it can then make it’s its way into walls and floors. In times of high condensation. We are proactive and place kitchen tissue or a rolled tea towel at the bottom of windows to catch running condensation before we can get to it.
In our van, every morning you’ll hear the whir of the Kärcher window vac’ as it ensures all the windows and glass is nice and dry.
Final Thoughts
Condensation might be unavoidable, but it’s easily managed with a few smart habits. Keep air moving, reduce moisture at the source, and stay on top of cleaning and drying. Do that, and your motorhome will stay fresh, dry, mould and damage free,
Links to Condensation Discussions on the Forums
This is a topic that is often discussed on our forums, have a read, you are bound to pick up a few Funster tips and tricks to keep condensation away.