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The Unseen Threat: How to Prevent Condensation Under Your RV Bed

One of the first unexpected issues we discovered in our first autumn RVing experience was condensation. The math is simple: warm interior air plus a cold wall or window equals condensed water vapor droplets. The first place you’ll find this is on your windows, which are easily toweled up. Then, you’ll notice it on the walls furthest from the heat sources. Again, not too hard to notice and deal with. Then, however, you eventually find the condensation under the RV bed.

This moisture can lead to mold and mildew growth when it lurks beneath your mattress for too long. It can also pose potential health risks and put a damper on your RVing experience. Today, we’re investigating the causes of RV condensation, and some simple hacks on how to prevent it from becoming a problem under your bed.

Let’s get started!

mold from condensation under rv bed
We found mildew and the start of water damage from condensation under our truck camper RV bed.

Why Do RV Campers Have Issues With Condensation?

Condensation occurs when water vapor contacts a surface cooler than the dew point of the surrounding air. It’s the moisture that forms on surfaces when humid air meets a colder surface, like a window pane or the underside of an RV bed.

Moisture buildup happens in cooler weather because we typically have our RV windows closed. Water vapor from showers, cooking, cleaning, and breathing has nowhere to go. RVs are compact spaces, which makes it easy for moisture to build up quickly. If there isn’t enough ventilation, the limited airflow can exacerbate moisture-related problems. Many RVs also face varying climates as they travel, which can lead to temperature and humidity fluctuations that contribute to condensation.

Furthermore, RV furnaces burn propane, which releases a significant amount of condensate. Heat pumps and electric heaters typically won’t give you as many condensation problems, but you’ll still have some.

Finally, RVs are not as well-insulated as traditional homes. This provides more opportunities for warm, humid air to contact cold surfaces and create condensation. With thinner walls and less insulation than sticks-and-bricks homes, they are less effective at maintaining a consistent temperature and humidity level.

Commonly Missed RV and Vehicle Maintenance Items | Preventing Catastrophic Failure and Breakdowns

What Causes Condensation Under RV Beds? 

Several factors contribute to condensation forming under an RV bed, and understanding these causes is the first step in preventing the issue. The first significant factor is temperature fluctuations, especially when the RV mattress is up against an exterior wall or floor. The difference in temperature between the interior and exterior of the RV can result in condensation.

For example, we had condensation issues under our truck camper’s bed because the bed essentially rests on the floor of the cabover area of the RV. There is little insulation between the exterior fiberglass and the underside of the mattress.

Furthermore, inadequate ventilation under your RV bed can worsen the condensation problem. Limited airflow prevents moisture from escaping, allowing it to accumulate under your mattress and on your walls and windows.

RV mattress by window
Condensation can form under your RV bed mattress and get moldy, especially when they are up against external walls.

How Do I Stop Moisture Under My RV Bed? 

Preventing moisture buildup under your RV mattress is essential for your comfort and health. It all starts with managing temperature and ventilation in this high-risk area. Here are some practical strategies we use to help eliminate RV condensation under our bed. 

Lift Mattress When Not In Use

One simple but effective way to combat condensation is to lift your RV mattress when you aren’t using it. This allows air to circulate underneath, preventing moisture accumulation. This should be your immediate response if you discover moisture build-up under your bed. It also allows warm air to heat the

Keep Your RV Dry

Moisture control starts with keeping your RV as dry as possible. This includes using vents when cooking or showering to reduce humidity levels and utilizing moisture-absorbing products like silica gel packs or desiccant bags in the bedroom area

If you can, running a high-powered dehumidifier is an effective way to reduce the moisture content in your RV. Other options include running the air conditioner or alternating between the air conditioner and heat to remove humidity.

Pro Tip: Keep your RV dry by using one of these 6 Best RV Dehumidifiers and Why You Need One.

rv dehumidifiers
An RV dehumidifier can help keep your RV dry and prevent mold from forming.

Insulate Under And Behind Your Bed

Improving insulation around your RV bed can go a long way in preventing condensation. You can add insulation panels or foam boards to the areas under and behind the bed to create a barrier between the warm interior and the cold exterior. This helps minimize the temperature differential that leads to condensation.

Use a Ventilating Mattress Underlay

Investing in a ventilating mattress underlay can be highly effective, and it will probably end up being your long-term solution to moisture issues under your bed. You can purchase a premade mattress underlay for this purpose or make one yourself. You would lay your mattress on top of a material that would allow air to flow under it. 

Popular premade underlays include the Hypervent Aire-Flow Mattress Underlay and the SavvyRest Natural Bed Rug. However, if you’re looking for a cheaper, DIY solution, you can always use a product like these interlocking rubber tile mats. The tiles provide a convenient way to lift your mattress off its cold subfloor and allow warm air to travel under it. They’re also roughly $30 for 12 square feet. 

Jaderlu 12 Pack Modular Interlocking Cushion 11.6"...
  • [What's Inside]: Each package contains 12 tiled mats measuring...
  • [Easy To Install]: Made of durable, flexible materials, these...
  • [Easy To Clean]: The mesh design and sufficient thickness make...
We laid down some strips of foam under our truck camper mattress to help with condensation.

How Do You Get Mold Out of a Camper Mattress? 

If you’ve discovered mold or mildew due to condensation under your RV bed, you must address the issue immediately to prevent health problems and further damage. Start by opening windows and ventilating the area. Then, put the mattress outside to prevent spreading mold spores in your RV. After putting on protective clothing like a mask and gloves, brush off any loose mold with a stiff brush. Mold can cause severe respiratory problems and other health issues, so you’ll want to avoid inhaling mold spores or touching them with your bare hands.

Next, clean the mattress with a mold remover solution. One effective mixture includes one-half rubbing alcohol and one-half water. Mix the solution and use a spray bottle to coat the affected areas generously. Then let the solution sit, preferably in direct sunlight, for 10 to 15 minutes to kill the mold. Once you’ve let it sit, scrub any remaining mold with a damp rag. Repeat the alcohol mixture if there are stubborn moldy spots. Once the mattress looks clean, let it sit in the sun until it’s completely dry. 

If you have an extremely moldy mattress or are suffering from persistent health problems, consider replacing the mattress. Your health is the priority, and sometimes the mattress is not worth saving. If other parts of your RV are covered in mold, do not try to live in it. Immediately find other living accommodations until you can effectively remediate it. Mold is not something to mess with. 

Pro Tip: Do you suspect mold in your RV walls? Here’s what you need to know.

How To Prevent Mold Under Your RV Mattress | Coir Bed Mat | Froli System Alternative

Stop RV Mattress Condensation in its Tracks 

Condensation under your RV mattress may be an unseen threat, but it doesn’t have to be an insurmountable one. By taking preventive measures and jumping into action the minute you detect moisture or mold, you can ensure that you and your family have a comfortable and healthy RVing experience.

It’s crucial to understand the causes of condensation, especially in an RV. Our beloved homes-on-wheels are much more prone to moisture issues than sticks-and-bricks houses, and we need to take care of them accordingly. Remember, a well-maintained RV is the key to enjoying your adventures on the open road to the fullest!

Have you ever dealt with condensation under your RV bed? Tell us your experience in the comments below. 

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About Cait Morton

Co-Founder, Logistics Queen, Business & Content Manager, and Animal Lover

An Upper Peninsula of Michigan native (aka a Yooper), Caitlin is the organization, big-picture, and content strategy queen of our operation. She keeps everything orderly and on track.

With a background in Business Management, she supports and helps channel Tom’s technical prowess into the helpful content our readers and viewers expect. That’s not to say you won’t find her turning wrenches and talking shop – RV life is a team effort. She keeps the business and the blog moving forward with a variety of topics and resources for our audience.

Believe it or not, she is rather camera shy, though she co-hosts the Mortons’ personal videos and The RVers TV show.

Caitlin’s passion lies in outdoor recreation and with animals. Some of her favorite things to do are hiking, biking, and getting out on the water via kayak, SUP, or boat.

She also loves the RV life due to the fact that you can bring your pets along. Sharing information about safely recreating outdoors with your whole family – pets included! – is very important to her. Because of this, Caitlin spearheaded the launch of HypePets in 2023.

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Shasta Price

Sunday 5th of November 2023

This is a great read. We deal with this and I needed some helpful advice. This did the trick. Thanks


Sunday 29th of October 2023

Great advise! Thanks for bringing this to our attention. I'm researching for going full time in a motorhome in about a year.