how to stop condensation on your windows overnight

We all love the comfort of dwelling in vans. Well, I do, but I have been called crazy a few times in my life.

I guess if you call liking to save a bit of money while cutting down on unnecessary crazy, then yeah, let’s strap me down and throw me in the loony bin.

The minimalist, nomadic lifestyle that van living affords us can be a fulfilling journey – and with good reason too. But that’s not the focus of this write-up.

It’s true, most good things in life are laced with their drawbacks, and we won’t pretend that van dwelling doesn’t bring about its own headaches sometimes. In this write-up, we’ll be focusing on the problem of humidity in vans, and how to stop condensation on windows overnight.

One thing we didn’t look into too much was condensation build-up. 99% of the van builds I saw included a roof fan, so I figured this, coupled with some open windows, should be enough for me.

This just isn’t true for everyone.

If you live in a high humidity region, you’re gonna encounter moisture build up in your van, despite taking the necessary precautions of an exhaust fan and a cracked window. You’re gonna have to do ALL of these things to the 10th degree. It will make all the difference.

What Causes Humidity and Condensation in Vans?

One primary reason for this is the enclosed nature of vans. The need to keep creepy crawlers out of your space often means that we keep the interior of the van sealed. But this also means that the humidity that the body, cooking (and so on) generates has no way to escape. Welcome, humidity. Moisture buildup can lead to mold, rust and an overall sticky and uncomfortable experience, and that besides the risk of significant health issues.

So how can we reduce condensation?

Exhaust Fans

These are conventionally situated on the roof, and for this reason are also called roof fans. They help with humidity control by sucking out the hot air and creating airflow through the van. These fans operate on the principle and expectation that hot air rising towards the roof contains more vapor. So sucking this out reduces the humidity within. Easy.

We personally chose the Maxxair 5100K, which we got locally at an RV store for a comparable online price. No waiting, instant pricematch. 

Opening windows

Sometimes, a quick and easy solution is needed – one that doesn’t involve getting huge appliances – and what better one than to leave the windows open so as to release the humid air.

My mistake was assuming two cracked windows and a single exhaust fan would suffice in Houston’s summer humidity. The more windows open, the better. You can have a dozen fans circulating air, but with no fresh air circulating in, by morning, you’re asking to wake up to an uncomfortable, cold sweat.


These are amazing devices which help considerably in the fight against moisture buildup within your van. They are a van-owners friend and work by catching the water vapor present in the air and converting them into water, which collects into a container for efficient disposal. A downside to dehumidifiers is their overreliance on electrical power, which could be limiting in a practical sense.

Damp rid

These are what you call moisture trappers. As the name says, it rids your van of dampness. Moisture trappers are made of carefully-formulated crystals, which absorb excess moisture from any air sample they’re exposed to. They are also said to work well against mustiness and smells, making them an excellent companion to the van dweller.

Increasing temperature

Whether you’re fighting humidity with dry heat (for example by burning a wood stove) or you’re rather using propane heaters, the goal remains the same – to raise the temperature within the van and reduce the humidity therein.

Obviously, this does not make sense in the summer weather, but condensation definitely occurs in colder months, so using dry heat serves two purposes.

But other heating options include electric heaters, butane heaters and diesel heaters. Each have their own advantages and disadvantages, but overall, the goal is to raise the temperature, yet remain safe.

Covering pots and pans while cooking

This might seem inconsequential and possibly funny, but this simple habit really does go a long way in reducing humidity in your van. Did you know that cooking during winter (especially) adds so much moisture into the air? If you must cook, make sure the lids are closed, and that other measures of humidity control are in place.