How To Keep Moisture Out Of RV In Winter (causes, fixes & preventions)

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Why It Is Bad To Have Too Much Moisture In RVs

A few of our winter RV camping tips relate to the important topic of condensation. Motorhomes and travel trailers are small spaces that can be prone to experiencing condensation problems. Wet surfaces are unpleasant, but even worse, they can lead to serious problems in your rig and in your body.

Visual Clues

RV windows can be double or single-pane windows. It’s easy to clean and dry the inside and outside of single-pane glass windows but they don’t provide as much insulation. Even though double pane windows offer better insulation, they can’t be cleaned or dried between the two window panes if the seal breaks causing moisture between the glass.

Your windows, are the window to your issues. Whatever type of windows you have, use them to guide you to your hidden problems.

Hidden Problems

If ignored, water droplets can cause moisture damage in RV walls, floors and roofs.

Mildew and mold growth can cause significant health problems for you and your loved ones as well as eat away at wooden and metal structures in your rig by causing rot and rust.

Water damage can be hard to detect in enclosed spaces so it is important to check every part of your RV including your closets, cushions, curtains and mattress on a regular basis. Make sure everything is clean and dry.

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What Is Relative Humidity Level & Why Does It Matter?

If warmer air can hold more water, why not just turn up the heat in your rig? The answer: relative humidity.

What Is Relative Humidity?

The relative humidity level is expressed as a percentage. It is the amount of water vapor that is present in air … compared to … the amount needed to saturate the air at a given temperature.

A lower percentage indicates the air has a lot more capacity to hold more water before water droplets begin to form on surfaces. A higher percentage indicates the air is holding more water and getting closer to its maximum level.

As the relative humidity level rises, you will eventually get to the point of 100 percent relative humidity at which water vapor condenses into visible moisture on surfaces.

When Warm Moist Air Inside Your Rig Collides With Cold RV Windows

The temperature difference between the inside air temperature and the outdoor air temperature matters. Even though warm air has the ability to hold more water vapour, it has issues when it meets up with cold surfaces. As soon as the warm air in your RV meets the cold temperature of the window, the air is cooled, reducing its water-holding capacity. Now, the relative humidity percentage just changed. As the air gets colder next to the window (that is being cooled by the cold outside air temperature) it can’t hold as much water vapor so condensation will begin to form on the inside of the window.

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Storing RVs vs Using Them In The Winter

When you are using your RV, you are adding moisture into the air. The majority of that moisture comes from cooking, showering and by your normal body respiration process of breathing. While an RV is in winter storage, it can have moisture problems too. We’ll discuss both cases.

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How To Prevent Condensation From Forming When Using Your RV In Cold Weather

The best way to keep condensation out of your rig is to decrease the amount of moisture you are putting into it. The trick is to limit your moisture-producing activities as much as possible.

9 Most Effective Ways To Minimize High Humidity In Your RV

1. Use the public restroom facilities at the campground for showering. No more fogged mirrors and walls in your RV bathroom.
2. Spend time outside. You know how your breath can fog up a mirror? Your body’s normal breathing process produces moisture. So, the more time you spend outside, the less moisture you are producing inside. Make sure you are dressed in proper winter camping clothes to stay warm while you’re out there.
3. Cook outside. When you are cooking using pots and pans on your stove, in your oven, or even using an instant pot or slow cooker, you are releasing steam inside your camper as you cook. Many of my winter camping recipes are designed to be cooked over a campfire using Dutch ovens. That gets you, your food and the moisture out of your rig.
4. Keep wet clothes out of your camper. Fully dry clothes after washing them in a public laundry facility. Leave wet items outside. We like to use the heat of a campfire to dry our wet socks, shoes and clothing before bringing it inside our RV for storage.
5. Use the propane furnace installed on your rig. There are many ways to heat a camper without electricity. Propane heat requires combustion. A byproduct of combustion is moisture. So how does an RV furnace produce dry heat? Your RV’s heater system is located outside of your rig. There are tubes located outside of your living compartment, the furnace heats the tubes. Air from inside your RV is forced over the heated tubes to get warmed, it is then routed back into your living compartment. All of the moisture-producing combustion is happening outside your RV. This is the reason we recommend a Diesel Air Heater when we are asked how to heat a tent without electricity.
6. Use an electric small space heater. If it’s so cold outside that your propane furnace can’t keep up, use an electric heater that produces dry heat to supplement it. Electric heaters take a lot of energy so it’s not always practical to use them. If you have to use a propane heater to augment the furnace and the combustion is happening inside your camper, just know that it is adding moisture into the air as it operates so limit its use as much as possible.
7. Insulate your floor and RV slide-outs. Installing extra insulation is a great way to keep cold air out in the first place.
8. Circulate the internal air. It’s a good idea to keep the interior air circulating to eliminate cold spots by maintaining a uniform temperature throughout your coach. Just like cold windows form condensation, other cold parts of your RV will do the same. Don’t forget to open closet and cabinet doors for circulation too. Trapped moisture in dark places can build up without being noticed.
9. Camp in dry climates rather than locations with humid air. Mother Nature can work with you or against you. Keeping your rig dry is easier in places where the weather patterns are naturally dry. Winter camping in Arizona makes it easier to keep your RV interior dry compared to winter camping in Florida.

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How To Remove/Reduce RV Condensation That Has Formed On Interiors

The best thing is to prevent condensation from forming, but the good news is that if it has formed, it is possible to drastically reduce it, even on a humid day. Or, even eliminate it completely with these tips.

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How To Keep An RV Dry While In Storage

If you don’t use your camper full time, you’ll need to do a little work before storing it for the winter to make sure it is completely dry. Here’s a quick checklist for you to dehumidify your RV and keep mold out of it while it’s in storage.

1. Drain the water system. After the system is water-free, it’s also a good idea to add RV antifreeze to protect the plumbing system from freezing.
2. Remove all wet items. Remember to remove all damp towels, empty the sinks and wipe up any spills.
3. Clean and fully dry the refrigerator and freezer.
4. Open cabinets, drawers and refrigerator/freezer doors for ventilation.
5. Store the RV inside or use a waterproof breathable cover. A little water can do a lot of damage. If you can’t store your RV inside, it’s best to use an RV cover to protect it from the elements over the winter, especially in cold, wet climates.
6. Place Damprid inside the open areas as well as inside closets and cabinets.
7. Check for leaks. Avoid inadvertent moisture in your rig by performing regular maintenance and inspections that check your pipes, drain, water lines, water tanks, water system and plumbing system are operating properly and not leaking prior to storage.

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FREE Printable Trip Planner

You may need to do a little extra planning for your winter camping trips.