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Which 12V RV Dehumidifiers should you buy, and why you need one

…So you have condensation in your RV.

Excess moisture left unchecked can eventually lead to the growth of mold, and potentially lead to health concerns in your living space.

If you’re planning to spend your winter in a motorhome, or stay in a place with high humidity levels >30%) (like the coast) A 12v dehumidifier for your RV is the best way to remove excess moisture.

condensation in rv

Why does My RV get humid in the winter?

In the winter, the air outside is colder and drier than the warm, moist environment inside an RV. This is due to the basic principle of physics where warm air can hold more moisture than cold air.

This warm, wet air from inside the RV is known as water vapor. It turn into water droplets when it touches cold surfaces like windows. This leads to condensation and higher humidity levels.

This happen more severely in a small enclosed space such as RVs with poor ventilation. Daily activities such as cooking, showering, and just breathing adds to the moisture in the air. Often times, Moisture absorbers just don’t cut it. This is where a Small RV dehumidifier can make all the difference to remove excess moisture to keep RV clean and your living environment comfortable.

What To Look For When Buying a Dehumidifier for an RV

What Size do I chose?

The best size of dehumidifier for your RV depends on two things:

      1. The size of your RV (Interior sq ft )

      1. Outside temperature and humidity. This varies greatly by region and season.

    Typically you wont need a large dehumidifier in an RV, as RVs are usually smaller than a traditional home. However, larger spaces like a 43-foot toy hauler requires a greater size dehumidification. While a compact cab over camper will require a small dehumidifier.

    To find the most suitable RV dehumidifier the inside of the RV must be measured and matched with a dehumidifier that is rated for that sq ft. Start by measuring the cabin space and calculating sq ft. Then find a unit that has an effective range for that sq ft.

    Will you be using this for the entire living space? or only a closet, bathroom, or bedroom? If so a 100-200 sq ft unit should work great for moisture removal in most spaces.

    Humidity & Temperature

    Ask yourself this… Will you be in Albuquerque or Albany? What time of year will it be? The moisture and humidity levels will vary greatly depending on these answers.

    If you know where you will be traveling you can check the weather forecast to determine your needs. Even if you are planning six months in advance you will be able to look up temperature and humidity for a given area of the country.


    The majority of dehumidifiers regardless of their size have a fan. Fans generally make a calming white noise. If having something that is quiet is a priority, then buy one that has NO compressor.

    Only certain designs are completely silent. These are generally car dehumidifiers that use a crystallized silica gel to absorb excess moisture removal. My warning about these is that they only work great in places that have low relative humidity.

    Water Tank Capacity

    Small dehumidifiers typically have a water tank capacity of 10-36 oz, with an average of about 20 oz. This is quite the contrast from a large dehumidifier that hold up to 350 oz.

    The unfortunate tradeoff of using a mini dehumidifier is that the water tank capacity is much smaller and fills much quicker.

    Find a dehumidifier with automatic shut off mode. Most modern brands have an auto shut off mode which turns the machine off to avoid overflow. This is an important feature to keep in mind.

    Dehumidifiers with a Drain Hose

    Installing a drain hose on your dehumidifier will eliminate the need to empty the water by hand whenever it becomes full. This will also ensure that the dehumidifier will continue to run despite the use of an auto off feature, which in this case you actually want to bypass. Another reason im such a fan of Eva-dry is because they sell drain tubes for most their models.

    The Benefits of 12 Volt Dehumidifiers

    If you’re looking a way to get rid of excess moisture in air, then a 12V dehumidifier is a great choice. They’re energy-efficient, compact, and can work effectively in RVs without eating up too much space.

    12 volt dehumidifiers run off a normal 12 volt making them more friendly to smaller RVs and car campers. These mini dehumidifiers are known for their portability and fit well in a small space.

    There are several options that operate both on 12v or traditional 120v. This is my to go feature because offers the most versatility.

    Boondockers who operate solely on solar panels and marine batteries will have to consider electrical use more carefully.

    If you are seeing a lot of “Eva-dry” models, that is because Eva is leading the market for 12 volt dehumidifiers. They are a solid company with an excellent reputation.

    12v Dehumidifier FAQ

    What size dehumidifier do I need for my RV?

    For smaller RVs and pop-up camping, you may go for a non-electric dehumidifier but as you gain bigger spaces of over 100ft you may be looking for mini dehumidifiers that can remove moisture in a 100 to 150 sq. ft area. Start by measuring your living space.

    What kind of dehumidifier do I need for an RV?

    I recommend a portable dehumidifier based on the size of your RV. Based on your power requirements you can use a 12v or traditional 110/120v plug in.

    Do they make cordless dehumidifiers?

    Yes, rechargeables and wireless. Ideal for a small spaces. These dehumidifiers are made with crystallized silica gel. They come cordless and do not require a rechargeable lithium battery. Best of all they continue to work during a power interruption.

    What is the best way to dehumidify an RV?

    The best way to dehumidify an rv is to use a mini dehumidifier that runs on electricity. Such as the Eva-Dry 2500. This unit operates on both 12V DC 6AMP, or a normal 110/120v outlet. Set it at 50 % humidity.

    Should I use a dehumidifier in my RV during the winter?

    Absolutely. Dehumidifiers can help minimize window and wall condensation, ultimately preventing the growth of mold and musty odors.

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