Do You Really Need An RV Dehumidifier?

Do You Really Need An RV Dehumidifier?

Regardless of where you live or store your RV, at some point, you’ll need to manage the humidity in your RV.  Managing moisture inside your RV is critical to your rig’s longevity and your enjoyment of this valuable asset.

Obviously, humidity is higher in some regions of the country than others, but regardless of where you’re located, it is a ubiquitous problem for all RVers because we all exhale.  Through a process called “insensible water loss” the average person loses about 23 fluid ounces of water through their skin and breath daily.

If there are two people and two dogs inside an RV for 24 hours, there will be approximately 60 fluid ounces of extra water in the air just from them. That is in addition to any humidity that may result from condensation on metal and glass surfaces or that enters the RV through the doors and windows.

If you’re cooped up in your RV for a week with little outside ventilation, the amount of airborne moisture circulating throughout your coach could be several gallons of water.  And that is a problem!  It will gather on hard surfaces, penetrate soft surfaces, get into the insulation, and under the wall treatments.  Water in the air will cause poorly ventilated areas to mold, and none of these conditions are desirable.  It’s not good for humans, pets, or the rig.

Areas with high humidity

If you are RVing in an area with high humidity, this problem is only compounded by the relative humidity in the ambient air. We’re originally from the Pacific NW where the weather is notoriously wet. But we had no idea what real humidity was until we traveled to Florida at the end of October 2019. 

Not only was the temperature an unbearable 95 degrees, the humidity was so high we were drenched just walking across the parking lot and literally could not catch our breath because of the oppressive humidity. We needed to transfer our RV gear from the older RV to the one we had just purchased, and this simple physical activity was nearly impossible due to the combination of heat and humidity. 

The air and surfaces inside the coach were damp the whole time we were in that climate. Once we got back on the West Coast, the coach began to dry out, but only because the humidity outside was low and we were able to open the windows for ventilation. 

Now we’re back in the Pacific NW, and it’s too cold and wet to open the windows and the humidity from insensible water loss has been building up in the rig for days. Now we need to take active measures to manage the humidity in the RV. Fortunately, we travel with an electric RV dehumidifier to help us combat the accumulation of moisture. 

What problems are caused by humidity?

How important can this be you may ask? If you only take your rig out on the weekends and it’s in storage the rest of the time, is managing humidity in your RV really that important?  Yes! 

One of our friends was very careful to close up his rig and cover it with an RV tarp when it was not in use.  In the spring when he got ready to de-winterize it, he noticed some damage in the headliner even though there was no way that the roof was leaking. 

On further inspection, he discovered that the entire surface under the headliner had been damaged by dry rot and all that damage was the result of humidity.  He was forced to sell that rig and in his next RV, he was diligent to manage the build-up of moisture.

How do you control humidity in an RV?

There are many ways to control humidity.  Even if your rig is in storage, you will still need to manage the humidity inside of the rig.

Dry air inside an RV is ideal. Wet air inside an RV is a problem waiting to manifest itself in mold, decay, and destruction. The most efficient method to reduce water in the air is to use an RV dehumidifier. 

What is the best RV dehumidifier?

There are many different types of RV dehumidifiers, from dry pellets that are used inside a special housing, called Dri-Z-Air or DampRid which are manufactured and sold for the RV industry, to dozens of electric dehumidifiers. Other options include the Air-Dryr and the Eva Dry, as reviewed in the video below by Youtuber Forrest Stevens.

We have tried the dry pellets but they only remove limited amounts of water. The pellets need to be replaced frequently, and the pellet’s absorption of moisture creates unpleasant toxic wastewater.

We have also tried three different electronic dehumidifiers.  The first one was huge, heavy, and noisy.  It could extract quarts of water daily, but it was always in the way because it was so large. 

The second dehumidifier was actually two separate countertop-style appliances. Those were very small, quiet, and completely useless in terms of the volume of air from which water needed to be extracted.  These small countertop units might have been fine in a closet or small bathroom but in our 33-foot Class A motorhome, they were no match for the build-up of moisture. 

The third RV dehumidifier (pictured at the top of this article) is actually very efficient. It is relatively compact and compared to the first one, it is also relatively quiet. It will extract quarts of water in an eight-hour period and it can be easily repositioned from one end of the RV to the other.

Even with this device operating all day, we are barely able to keep up with the accumulation of water in the air when the outside conditions are wet. We’re in Oregon, in the winter, and unfortunately, it’s always wet. Whenever it stops raining, we can open a window to ventilate the rig, but it’s the Oregon Coast, and it’s always raining.

Make sure you also have a quality hygrometer like this one to monitor the humidity levels in your RV, whether you’re on the road or when your RV is sitting in storage for the winter.  For more tips, check out this article from Do It Yourself RV on How To Reduce Condensation In Your RV.

Peggy Dent

I am an author and writer, my partner is a web designer. We are full time RVers traveling around the US and Canada. We’ve been RVing for over 20 years and we’ve traveled more than 130,000 miles in an RV.