How To Manage Condensation and Moisture in an RV


Tucker Ballister

Favorite Trip

5 Months Solo on the Road

Home Base

Hendersonville, NC

Favorite RV

2008 Fleetwood Bounder

About Contributor

Tucker Ballister is our Content Strategist. He’s a lover of the open road and the proud owner of a 2021 Sunlite Classic travel trailer (his 3rd RV to date). Check out more of his RV adventures, gear reviews, and outdoor advice at

Moisture in an RV is never a good thing. It’ll make your RV feel cold and damp and can lead to costly repairs if left untreated. If you want a warm, dry, and healthy living space, you need to know how to manage condensation and moisture in an RV.

You don’t have to get the air dry as a bone, but make sure to take these steps to manage condensation and reduce the moisture levels inside your RV.

Ventilation Is Your Friend

Camper Van Clear Glassy Roof Vent. Air Circulation in the Motor Home.

Keeping moisture levels in your RV low is in your best interest for several reasons. It reduces mold and mildew growth and other moisture-related issues like rotting wood and rusting of your RV’s metal components. 

Too much moisture will cause a variety of issues in your RV. It can lead to replacing a moldy mattress and reconstructing damaged subfloor and wood framing. Unmanaged moisture accumulation can also lead to a rusted chassis or the need to fumigate your entire RV to remove mold and mildew growing inside the walls and insulation. 

Fortunately, these issues are avoidable and ventilation is your biggest ally in this battle. Your fans and windows allow you to circulate air more efficiently and expel moisture that accumulates when you’re cooking or showering (two of the most common sources of moisture creation in RVs). Use your vent fans to your advantage!

How To Manage Condensation on Windows

Water dripping in front of RV

Opening a window is one of the best ways to dry out your RV. Unfortunately, outside temperatures don’t always make it a comfortable choice. So let’s discuss all your options for window condensation management. 

If you do open your windows to reduce your RV’s moisture content, make sure you have screens for all your windows. That way you can open them and let a breeze blow through without allowing bugs in. 

In some cases, you’ll need to open your windows more selectively because it defeats the purpose when camping in a humid destination. Only open your windows if absolutely necessary in humid climates to keep humidity down and the interior of your rig feeling comfortable. 

If you’re winter RV camping, opening your windows isn’t really an option. Fortunately, your RV’s furnace will naturally dry things out inside. Additionally, you should consider adding an RV dehumidifier if you’re noticing a lot of condensation on your RV windows. 

How To Manage Moisture Inside RV Windows

Photo by Paul Maguire via Shutterstock

Another RV moisture issue is condensation developing inside double pane windows. While double pane windows are great for insulating your RV, moisture can get between the panes if the seal is compromised. 

There are several reasons that window seals break down. On average, window seals last 10 to 20 years, but they can degrade more quickly if there’s inadequate drainage around the window or they’re exposed to too much direct sunlight. 

When the seal is compromised, moisture accumulates and results in a foggy window. If this happens to the side windows in the cockpit, for example, it creates a significant driving hazard. To fix this issue, you’ll need to remove any valances over the window, unscrew the window and remove it, and then separate and clean the two panes of glass. 

After that, you’ll need to re-install the window and seal around it to prevent moisture from re-entering between the panes. For more details on this process, check out this article on replacing dual-pane RV windows.

DIY Defog Hack

As a temporary solution, you can use a steam iron (yes, the kind you use to iron clothes) to de-fog double pane windows. Use the lowest heat setting and move the iron over the fogged area for 5 to 10 minutes. 

Keep the iron moving to avoid prolonged contact in one spot. To be conservative, place a paper towel between the iron and the glass. Keep in mind that this is a temporary solution that will need to be done regularly depending on your environment. 

In colder conditions, it could be necessary on a daily basis. In warmer conditions where there is less temperature difference between your RV’s interior and the outside air, you should have to use this technique less frequently. 

This technique is only necessary for the side windows in your RV’s cockpit. It will enable you to de-fog those windows so you can see your side-view mirrors and drive your RV safely until you permanently fix your fogging issues. 

Please note that placing an iron on your RV windows for too long CAN result in damage. Be careful and cautious if attempting this technique and know that fully repairing or replacing your windows is a more permanent solution.

How To Manage Condensation in the Bathroom and Kitchen

Photo by Arina P Habich via Shutterstock

Whenever you’re using the bathroom or cooking in the kitchen, open your roof vents. Boiling water or taking a shower adds a lot of moisture to your RV. Turning on the fan over your cooktop or in the bathroom will move moisture out and circulate dry air back in.

If the weather is favorable, you can also cook outside. If your RV has an outdoor kitchen, utilize it. If it doesn’t, consider getting a good portable grill. Cooking outside is a great way to reduce moisture content inside and keep your rig cool and energy-efficient by cutting down your AC usage

If you don’t want to cook on a gas grill, think about cooking over a campfire. While you probably won’t do this all the time, it’s a fun way to cook a meal and an effective method for managing condensation in your kitchen. 

Another good way to keep RV moisture levels down is to take shorter or colder showers. Hot showers contribute a lot of steam to the air, but this will be less of a problem if you take cold showers.

A good bathroom ventilation fan should handle most of the moisture, but reducing the length of your showers or the temperature of the water helps considerably. It also reduces energy and water consumption, which is a smart thing to do while camping and/or boondocking

How To Manage Moisture Underneath Your RV Mattress

Photo by Virrage Images via Shutterstock

Another moisture-related issue that some RVers experience is moisture underneath their mattress. This happens when your RV mattress rests on a cold surface and the heat from your body warms it up while you’re sleeping. 

The temperature difference between the cold surface and the mattress itself causes condensation to form on the underside (or even the inside) of the mattress. In some cases, you may not notice this happening unless you lift your mattress to check. 

If left unchecked, it leads to mold growth that will eventually rot the wood underneath your mattress. Sleeping on a moldy mattress every night can also have negative impacts on your health and the health of anyone else living in your RV. 

So, this is an issue that needs to be checked regularly and treated effectively. Here are three major signs that you may have mold growing underneath or inside of your mattress: 

  • Allergic Reactions: If you wake up constantly with a runny nose or swelling around your eyes but these symptoms subside within a few hours of getting out of bed, check for mold growth under your mattress. 
  • Strange Odors: Mold can grow very quickly in the right environment, but you’ll generally smell a musty odor before you actually see mold accumulation on your mattress. 
  • Visible Wet or Moldy Spots: If you find visible wet or moldy spots when you lift your mattress, it’s time to dry things out and you may need to replace your mattress altogether. 

Catching condensation under your mattress early is important, but you’ll need to know how to alleviate it once you do. So here are a few tips to manage condensation and reduce moisture build-up under your RV mattress: 

Air Out Your Mattress

Photo by sylv1rob1 via Shutterstock

One of the simplest ways to reduce mold growth is to circulate more air underneath your mattress. Begin by removing all bedding and propping the mattress up so that it can receive direct sunlight for several hours.

If you can’t move your mattress by yourself, add spacers underneath to prop up one side at a time. You can use almost anything as spacers, such as canned goods, step stools, water bottles, or anything else that will support the weight of your mattress. 

If you have a portable fan or a small RV dehumidifier, place it next to your mattress to speed up the process. The length of time you’ll need to air it out will vary, but you want the underside of the mattress as well as the wooden platform below to be 100 percent dry before you set the mattress back down. 

Rotate Your Mattress Regularly

Photo by evrymmnt via Shutterstock

Not all RV mattresses can be rotated, but this is a great way to reduce moisture accumulation if yours can be. Rotating your mattress every month or so will maximize its lifespan and make it easy for you to check for condensation on the bottom. 

If you find wet spots when you rotate your mattress, prop it on its side and place a fan or portable heater 12 to 15 inches away to dry it out. A fan can be placed closer but heaters need to be kept at a safe distance to avoid damaging your mattress or starting a fire.  

Insulate Under Your Mattress

Photo by Virrage Images via Shutterstock

To avoid regularly flipping or drying out your mattress, consider adding an insulating layer to reduce the temperature difference between the mattress and the cold wooden surface underneath. 

One of the most budget-friendly ways to do this is to place cardboard or bubble wrap insulation underneath your mattress. This is a cheap fix, but you’ll need to check it weekly to make sure it isn’t absorbing too much moisture and you’ll probably need to replace it every 1-2 months. 

As an alternative, you can insulate under your mattress using a mattress topper or a mattress underlay. Because mattress toppers are usually made of foam (which can also absorb moisture), they’ll still need to be checked and replaced every 2-3 months. 

That makes mattress underlays the most long-lasting way to prevent condensation under your RV mattress. These underlays are usually made of a hard plastic or polymer material and they create enough space under your mattress to promote regular air circulation and prevent mold growth. 


Photo by JaySi via Shutterstock

Whether you’re renting an RV, shopping for used RVs, or buying a brand new model, learning how to manage condensation and moisture in an RV is an essential part of your journey. It’ll maximize the lifespan of your rig and help you keep the interior feeling as comfortable as possible. 

If you have any major moisture-related issues in your rig, please don’t hesitate to reach out to a local Camping World specialist. Our team is here to help you resolve your issues so you can get back to enjoying the many benefits of living in an RV!

How do you manage the moisture levels in your RV? Leave a comment below!

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