What should the humidity be in an RV? (9+ tips)

In this article, we will answer the following question: ​​What should the humidity be in an RV? We will share ten important tips on how to reduce and maintain a proper humidity level in your RV. 

What should the humidity be in an RV?

The ideal humidity level in an RV should be between 30% and 50%. If the humidity level regularly exceeds these values, it can cause rust, mould, musty odour and rot – in a word it can cause condensation problems. To remedy this, dehumidification must be carried regularly. 

Condensation can develop quickly, especially in cold weather. Small water droplets can develop on the walls of your RV and along with any metal inside the platform. High condensation can damage walls, floors, furniture, cabinets, and mattresses by causing mould to form, rotting wood and also causing corrosion of metal.

How to reduce moisture and condensation in your RV?

Condensation in your RV is caused by the increased volume of water in the air, and most often because we have exhaled it. This air, full of water vapour, touches something cold, for example, a window.

The air is then cooled too quickly and can no longer retain the moisture it contains so that the vapour turns into liquid on the cold surface it touches. The condensation is in the coldest part of the motorhome, ie the window of the front cabin because it is not really heated.

The best way to stop condensation is to eliminate its cause:

  1. Reduce indoor humidity: Ideally, your indoor relative humidity should be between 30% and 50%. Once you have identified your humidity level and if there is indeed a problem, you can try the following.
  1. Operate the air conditioner: Leaving the windows open in your motorhome during the summer in a humid climate can lower your electric bill, but there is a trade-off, as air conditioners remove moisture from the indoor air. If it’s hot enough to run the AC power, that alone can fix the problem.
  1. Open a window or ceiling vent: This is the opposite of what we just said, but if the indoor air is more humid than the outdoor air, opening a window or ceiling vent may help part of this moisture to escape. Keep in mind that hot air rises, so a ceiling vent will work better than a single window. 

This is especially important when performing activities that create a lot of extra water vapour, such as taking a shower or cooking. A simple solution, but not always fun if it’s freezing or raining. Bringing in the air with less water vapour reduces humidity. You can always open a ventilation duct when driving.

  1. Increase the airflow:  If you have a window or an open vent, a fan will help the moist air to escape more quickly. Good ventilation and aeration of your RV are important.
  1. Run a dehumidifier: A dehumidifier can help you remove moisture from the air. Dehumidifiers come in a range of sizes and prices, you just need to make sure you have one designed for the space you are using it in. You can ask a professional for advice on this kind of accessory.
  1. Use moisture absorbers: When your motorhome is in winter storage and operating an electric dehumidifier is not an option, moisture absorbers can help extract moisture from the air. You can also create your own moisture absorber. Different models are available for all vehicles.
  1. Avoid creating additional water vapour: Taking a shower, cooking or hanging wet clothes inside your motorhome increases humidity and window condensation. If you’ve tried everything and you’re still having trouble, do your laundry in a laundromat and cook outside whenever possible.
  1. Means of removing cold surfaces where condensation may form: If you can eliminate the cold air and cold surfaces inside your motorhome, you won’t have to worry so much about lowering the humidity level inside, why? because cold air has a lower dew point (the temperature at which the air becomes saturated and condensation forms).
  1. Warmer air can hold more moisture: Plus, cold exterior walls, floors, and windows not only cause condensation, but you also mean you lose heat. By strengthening the insulation of your motorhome, you not only reduce condensation but also spend less money on propane, gas or electricity and your vehicle will be less exposed to drafts.
  1. Other small but important tips you can implement:
  • Insulate windows, check sealant, and waterproofing to consume less heating.
  • Warm up the soil. A warmer floor can help the temperature inside your motorhome stay warmer.
  • Insulate the slides. Another thing that can make a big difference is sealing any drafts around your slide joints and adding an extra layer of insulation.
  • Insulate the roof of your RV, check the exterior insulation.

How to detect a humidity problem in an RV?

The are several easily identifiable signs that indicate the presence of high humidity:

  • feeling of constant cold;
  • wallpapers that peel off;
  • musty smell coming from cupboards or walls;
  • cracked or peeling paint;
  • appearance of mold, brown halos or rust;
  • condensation;
  • blackening and detachment of plaster;
  • perpetually damp walls.

Please note: humidity has an impact on health. It causes respiratory problems, allergies, headaches, fatigue and eye irritation. Children and the elderly are particularly affected by this phenomenon.

After having detected the location, it is necessary to identify the source: pipes, joints, leaking pipe, etc. If you can’t find the exact location of the leak, call a pro. It is safer than trying to fix a leak yourself. Consider checking your RV’s insulation. Indeed, poor insulation can explain the presence of humidity in your motorhome or caravan.

The best dehumidifiers for an RV

There are a large number of dehumidifiers on the market. In order to make your choice easier, we have limited our selection to three products that we believe are the best for your RV in 2021.

1. Rubson Sensation Pure moisture absorber

The Rubson pure sensation is a discreet dehumidifier for small rooms of 10 m². This product is ideal for a small space such as a caravan. It effectively combats excess humidity, while preventing the appearance of mould and dust mites in your RV.

Design and compact, it has a long lifespan: a single recharge can last about 2 months. Odour neutralizer, each side of the “Tab Sensation” refill is made up of ultra-active crystals capable of combating bad odours and excess humidity …

2. Vivosun dehumidifier and defroster

The Vivosun is a dehumidifier specially designed for fogged and frozen RV windows from the inside. Ideal for small spaces, this dehumidifier prevents the appearance of rust and mould in your vehicle.

Designed from silica gel, this product can be reused after drying the cushion in the microwave or in a radiator, its duration of action is approximately 3 months.

3. Carlinea dehumidifier and anti-fog

The Carlinea is an effective solution for quickly removing moisture from your vehicle. Reusable, this moisture absorber is designed from silica gel to limit fogging and condensation associated with excess humidity.

Resistant, this dehumidifier retains water safely, without leakage. The plus of the product? This is equipped with an indicator: as soon as it turns pink, you must put the dehumidifier in the microwave for 6 minutes. After a few minutes, it will be usable again and the indicator on the bag will turn blue again.

Conclusions and final advice

One way to avoid condensation is to regularly open your cabinets and closets to equalize the temperature. You can also try making your own moisture absorbers from old socks filled with crystal (silica) litter. You can also add a layer of insulation to the exterior walls of your cabinets and closets.

The maintenance of your RV is essential. Check the waterproofing and insulation of your motorhome to leave without risk of frost in winter.

A well-maintained RV can be a travel companion for a long time and as you can see, preventing a high level of humidity in a caravan and dealing with mould is not complicated at all. We hope these tips have helped you.

Please let us know if you have any comments or questions about the content. 

FAQ on What should the humidity be in an RV?

How do I keep my RV in the winter?

To keep your RV dry in winter you must take some precautions and protect it from the bad weather and high humidity. To resume the new camping season without any bad surprises next spring, it is important to properly prepare your vehicle before winter arrives.

How do you stop condensation in the back of a van?

While completely stopping condensation in the back of a van may be a challenge, you can at least try to prevent and reduce humidity.  This goes through the important stages: good insulation, thermal bridges and efficient ventilation.

How to avoid condensation in a motorhome?

Running a fan can help evaporate condensation and evenly distribute the air temperature throughout your motorhome or caravan. If you have a window or an open vent, a fan will help the moist air to escape faster.

Can damp be repaired in a caravan?

Yes, damp can be repaired in a caravan, but it is laborious and expensive work. You will have to replace most of the structure of the caravan. 

How do I keep my RV damp-free?

To keep your RV damp-free you must keep it ventilated at all times, shower outside when possible, cook with the windows/door open, don’t dry your laundry inside the RV, invest in a good humidifier. 


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