How to Control Moisture in Your RV: Tips to Keep It Dry
Hi, we’re the McCartys—and we live full-time in our RV, trekking across the country in search of new adventures. If there’s one issue that still drives us crazy (besides running out of snacks mid-road trip), it’s that never-ending battle with excess moisture. Anyone who’s spent more than a few nights in an RV will know how quickly moist air can turn into a moisture buildup problem, especially during the winter months or in humid climates.
Left unchecked, humidity levels can lead to mold growth, water damage, and that dreaded musty smell. In the worst cases, you could even face structural damage—definitely something no RV owner wants to discover. We wrote this post to share the best way we’ve found to manage rv condensation, prevent moisture-related issues, and keep our living space feeling fresh and comfy year-round.
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Our Personal Moisture Struggle: 2 Dehumidifiers & One Pesky Window
We’ve been full-time RVers for a while now, and let me tell you: condensation forms in some surprising places inside of your RV. In our home on wheels, the biggest culprit is the large, slanted front window that loves to collect water vapor—it’s like a mini science experiment in cold weather. We’re talking literal beads of cold air dripping down onto the windowsill.
Because of that, we decided to run two small dehumidifiers 24/7—one in the master bedroom near that front window, and one in the main living area near the kids’ sleeping space. Even with these running nonstop, we still keep a towel wedged by the window to catch those stray droplets. Are we winning the fight? Mostly. But trust me, moisture control in an RV is an ongoing project!
Below, we’ve rounded up our favorite ways to manage moisture levels so you can keep your RV’s interior nice and dry, too. Whether you’re dealing with warm weather, cold climates, or just the day-to-day routine of everyday activities like cooking and showering, these tips go a long way to prevent condensation damage and dry rot.
Left unchecked, humidity levels can lead to mold growth, water damage, and that dreaded musty smell. In the worst cases, you could even face structural damage—definitely something no RV owner wants to discover.
1. Understand the Sources of Moisture
Good idea #1: Know where it all comes from! You might be surprised by how many everyday activities generate a lot of moisture:
Hot showers create warm air that hits cold surfaces, causing condensation forms.
Cooking on a propane stovetop or using proane heat can release moist air into the living area.
Breathing and body heat (yes, we humans produce water vapor) also adds to your RV’s humidity levels.
Wet clothes or wet items left to dry indoors can increase amount of moisture in the air.
Helpful notes: If you’re camping in humid climates or it’s cold weather season, you’ll likely notice an even higher relative humidity inside your rig, especially when the indoor temperature is warmer than the air outside. By knowing these sources, you’ll be more intentional about venting that moist air out.
Read More: The Magic of Winter RV Window Covers!
2. Ventilate Your RV (And Use Exhaust Fans!)
The most effective way to deal with moisture buildup is to let it escape. That means proper ventilation is key:
Open windows (or rv windows) whenever it’s safe and comfortable to do so, even in winter months—just a tiny crack can bring in fresh air and push humid air out.
Run the vent fan or exhaust fans in your kitchen when cooking. Not a lot of steam = less moisture buildup.
Use the bathroom vent during and after a hot shower to expel moist air before it settles on cooler surfaces.
For extra oomph, consider a small fan pointed outward (through a window) to pull moisture outside. It’s a great way to keep the moisture from lingering.
3. Choose Your Heat Sources Wisely
Propane heaters can introduce additional water vapor into your RV’s interior, so if you have the option, switch to electric heaters whenever possible. While propane is convenient for winter camping, keep an eye on your rv’s humidity if you notice a condensation problem increasing. If you must use propane, try balancing it with roof vents slightly open or a small fan that exchanges outside air to keep humid air moving out.
Read More: Double the Warmth: Maximizing Heat Sources in Your RV
4. Use Moisture Absorbers
Damp Rid and other desiccant crystals (like classic “moisture absorber” products) can be a lifesaver, especially in cabinet doors or closets where ventilation might be poor. These use moisture absorbers to draw excess moisture from the air. Here are a few good ways to place them:
Hanging bags in closets, which collect water drips at the bottom
Small containers or “tubs” in cabinets, under the sink, and near rv windows
Bathroom door area or laundry spaces prone to moisture build-up
Just remember to empty them regularly and replace the crystals as needed—moisture issues can get worse if you forget to check on them.
5. Utilize a Dehumidifier (Or Two!)
When people ask, “What’s the best way to keep your RV dry year-round?” our answer is simple: get a rv dehumidifier. They come in various sizes, from a small device (think small dehumidifier) to a larger portable dehumidifier. We personally have two running 24/7:
Front Window Dehumidifier: Positioned to catch water vapor from that tricky slanted window.
Living Space Dehumidifier: Keeps the main area and kids’ bunks from feeling damp.
For an even better handle on your humidity levels, invest in a digital hygrometer or weather station. This helps you track if you’re close to the dew point—the temperature at which condensation forms. If you notice a spike, that’s your cue to crank up the dehumidifiers or open a vent fan.
6. Keep Surfaces Dry
No matter how careful you are with ventilation, some cold surfaces—like metal window frames or window panes—will inevitably gather moist air that condenses. A good idea is to:
Wipe down windows, window frames, and rv’s interior walls in the morning (especially in cold climates).
Keep cabinet doors open if you suspect moisture problems might creep inside.
Check areas behind your rv mattress or seating cushions if they’re against an exterior wall—excess moisture can hide back there.
As we mentioned, we stash a towel near our front window to catch stray droplets. It’s the easiest way to avoid dripping water pooling up!
7. Insulate and Seal: Combat Condensation
If you’re in for a cold spell or planning on serious winter camping, you’ll need to be proactive with insulation. Condensation forms on the cooler surfaces of your RV, and “sandwiching” those surfaces with insulation can help raise their lower temperature closer to your interior’s warmer temperatures.
Shrink-Wrap Window Kits: We love these because they keep the warm air inside while still letting you see outside.
Foam Board or Reflectix: Stash it behind drawers or along basement storage bays.
Seal Cracks and Leaks: Inspect around vents, door frames, and pipes. If you see or feel cold air streaming in, close it up with weatherstripping or caulk.
This extra insulation also helps with energy efficiency, so you’ll use less heat to maintain a cozy indoor temperature.
Read More: Stay Warm and Dry: Extra Insulation Tips for your RV
8. Adjust Everyday Activities
Sometimes preventing a condensation problem is as easy as changing small habits:
Open the bathroom door after a hot shower but run the fan—this directs a lot of moisture outside rather than letting it settle on your living space surfaces.
If you have an outdoor kitchen, use it whenever possible to avoid pumping humid air into your RV.
Hang wet clothes outside or in a well-ventilated area with a small fan running.
Use lids on pots and pans when cooking to reduce moist air buildup.
These different ways of controlling everyday activities can do wonders for reducing rv condensation.
Staying vigilant is the most effective way to stop small moisture issues from becoming bigger moisture problems—like dry rot or condensation damage over time.
9. Keep an Eye on Humidity: Monitor, Monitor, Monitor
Just like checking the latest news or weather forecast, it’s wise to keep tabs on your RV’s relative humidity with a digital hygrometer or weather station. If you notice levels creeping above 50–60%, it’s time to:
Open windows for fresh air if the outside environment is drier than the inside.
Turn on the vent fan or an air conditioner (AC can help dehumidify if it’s warm weather).
Increase your moisture control efforts—run that portable dehumidifier on high, pop in extra desiccant crystals, and make sure no wet items are left hanging around.
Staying vigilant is the most effective way to stop small moisture issues from becoming bigger moisture problems—like dry rot or condensation damage over time.
10. Don’t Forget Maintenance & Storage
If you ever place your rig in an indoor storage unit or park it in one spot for a while (say you’re off visiting family for a couple of weeks), moisture-related issues can escalate fast if you ignore them. Before leaving:
Run a dehumidifier for a day or two to lower the RV’s humidity as much as possible.
Prop open cabinet doors, the bathroom door, and maybe even the fridge to keep fresh air circulating.
Make sure no wet items (like dish rags or damp clothing) are lying around.
When you return, do a quick check for musty smell or water damage. Early detection is a great way to nip issues in the bud.
Quick Recap: Your Roadmap to a Moisture-Free RV
Identify Moisture Sources: Cooking, hot showers, laundry, or simply living and breathing.
Ventilate Properly: Open windows, run exhaust fans, and use a small fan for targeted ventilation.
Choose Heat Wisely: Propane heaters add moisture; electric is often better.
Use Moisture Absorbers: Damp Rid or similar crystals in tucked-away spots.
Invest in a Dehumidifier: Our personal favorite for tackling excess moisture.
Wipe Surfaces Dry: Pay attention to rv windows, window panes, and metal frames.
Insulate & Seal: Cold surfaces + warm air = condensation forms, so reduce that temp difference.
Adjust Daily Habits: Cook outside, hang clothes carefully, and run the bathroom vent during showers.
Monitor Humidity: Use a digital hygrometer or weather station to watch humidity levels.
Stay on Top of Maintenance: Especially if you park your rig for a while or store it in cold climates.
Follow Us on Social Media!
If you found these tips helpful (and we hope you did!), come join us online for more relevant questions answered, helpful notes, and behind-the-scenes peeks at full-time RV life. We’re always sharing our latest camping spots, winter season strategies, and day-to-day shenanigans on the open road. Follow us on social media for real-time updates, Q&As, and more ways to keep your RV dry.
Final Thoughts: Stay Dry, Stay Happy
Controlling humidity levels in an RV isn’t about achieving zero moisture—there’s always going to be a bit of water vapor floating around when you’re cooking, breathing, or enjoying a hot shower. But with the right combination of proper ventilation, use moisture absorbers, and a small dehumidifier or two, you can keep moisture buildup from escalating into a full-blown condensation problem.
Trust us—we’ve been there, battling a stubborn front window that just loves to fog up every morning. Between wiping down cold surfaces and swapping out towels, we’ve learned that taking a few extra steps for moisture control makes all the difference. The result? A fresher, healthier rv’s interior, fewer moisture issues over time, and an RV that lasts longer—protecting both your comfort and your wallet from costly repairs.
So, good luck, RV owners, and safe travels from our family to yours! Remember that a tiny tweak—like running the vent fan more often or adding one more portable dehumidifier—can go a long way toward preventing condensation damage and keeping your rig cozy all year round. After all, the beauty of life on wheels is the freedom to move on to the next amazing destination, not to mop up puddles in your rv’s interior!
Happy adventuring, friends, and stay dry out there.