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Best RV tankless water heater

Last Updated: 01.12.22


What are the best RV tankless water heaters?


If you’re an avid outdoorsman and you’re used to traveling around in your RV then you probably are in need for something to heat up your water for showering on chilly days. So if you are looking for the best RV water heater, you’ll find that this short paragraph is sufficient in providing results. After we gathered information and we’ve looked through reviews, we came to the conclusion that the gas Flex 10011 is the best RV tankless water heater because it needs little water pressure to start, 2 PSI would suffice, unlike other water heaters that require at least 30 PSI. It is capable of delivering hot water instantly as you open the hot water tap, thus allowing you to save energy and water. Its beautiful design will prove to be a nice addition to your RV, making it a place that feels closer to home. In case this product is unavailable, we suggest that you look into the Eccotemp L10.



Comparison Table


The Good
The Bad



A short buying guide


We know that it is a time-consuming job to wander across the internet to find the right product. It is easy to get lost among the complicated features and characteristics, but if you’d like to find the best tankless hot water heater for RV for sale, then we invite you to give our informative guide a chance. We’ve also come up with some suggestions so that you’ll be able to find what you need in no time.



When you decide on purchasing a tankless water heater, you don’t need to concern yourself with the matter of capacity because it doesn’t come with a storage facility for water intake. Instead, you should look at how it allows the water to flow. When it comes to households, you’ll need something that is capable of generating enough heat.

For example, if your washing machine and your shower are working at the same time and your heater isn’t powerful enough it will result in lukewarm water. Instead of buying two items, which will be more expensive, look into a more powerful one.

For RVs, you should consider why you’ll need it for. Showering and dishes shouldn’t require much so you might not have to dig too deep into your pockets.




Here the choice is somewhat simpler. You can buy either gas-powered heaters or electric ones. The advantage of the water heaters that work on gas is that they are faster and more efficient. They run on either propane or kerosene, and they require venting, so take this into consideration.

You can find some products that can be installed directly outside to prevent you from having to figure out how to ensure enough ventilation. For increased efficiency, you can look for electronic ignition products as they don’t require fuel to maintain a flame.




Unlike models that store water, with this type of product you won’t have to concern yourself with its capacity, as we already said. The only concern should be if it is capable of heating up enough water in order to serve multiple tasks.

Look for the BTU (British Thermal Unit) input and the efficiency ratings because they determine its flow rate which is expressed in GPM (gallons per minute). So, the higher the BTU’s rating, the higher the water’s flow rate. If you tend to take your RV in cold places, then know that it might take longer for the water heater to do its job since the water is colder there.



Our top picks



gasFlex 10011 


Unlike other models which require up to 30 PSI of water pressure in order to start up due to outdated technology, this product works with only 2 PSI. If you are looking for a tankless water heater which is ideally made to fit into RVs, campers, rural cabins or small apartments as well as all kinds of boats and mobile homes, then you might want to take a good look at this product.

It is capable of saving water and energy thanks to its capacity of instantly delivering hot water after you’ve activated the tap. Since it is a vent-free appliance this model won’t require that you install costly flues or ductwork and that’s because it comes with state of the art oxygen depletion safety.

This unit is outfitted with a magnetic water flow sensor which will allow it to work even at low water pressure and this means that it’s ideal for use during RV trips.


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Eccotemp L10


If you are looking for a portable tankless water heater that is tiny enough to let you enjoy different outdoor activities while providing good performance, then we suggest the L10. It is able to fit almost anywhere, from RVs to an artist’s studio and can even be used to wash animals at your farm.

You won’t have to worry about getting a specialist in order to install it because you’ll see that the process at attaching it to your RV and making it work isn’t as troublesome as you’d think. It is able to provide 2.6 GPM of water flow making it ideal for small-scale application, meaning that it is great for your RV.

Another perk you might love is that this product is affordable, yet it is capable of providing hot water when you want it. Its rain cap is made from stainless steel in order to protect its interior heating parts, so don’t worry that it will rust.


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Eccotemp L5


Main advantage


The portability of this item is perhaps the most relevant feature there is to discuss under this topic, very similar to the L10 alternative that we’ve also reviewed somewhere else on the website, another product from Eccotemp.

In fact, most of the features are roughly the same, so it’s safe to say that this device uses a developed technology to allow its users to install it anywhere, and not to depend on outside factors as much.

It’s lightweight and easy to carry, you do not need much help to install it wherever you need to, and most importantly, this device does not require electrical power, since it runs on a 20 lb. propane tank and two D cell batteries.


Main disadvantage


This design does not feature an internal pump, so in order for it to work correctly, it needs to be provided with a minimum of 20 PSI and 1 GPM. Otherwise, if you want to use it without a pump, you might need to try to lift it high enough off the ground for it to have enough pressure to spray.

The exception to this issue would be the case when you draw your water from a pressurized source, perhaps inside the city. So if you’re planning to use this heater at home, you need not worry about this aspect, but if you plan to take it outdoors and use it for camping, please do consider this factor.

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Top 3 features explained



As we’ve stated before, the technology that this model uses manages to allow the customers to benefit from its portability and adaptability. This way, the heater does not require electrical power, since it works on two D cell batteries, which make it a good choice for camping or outdoor activities.

It runs on a standard 20 lb. liquid propane tank that provides electronic ignition.


Automatic shut-off is activated any time the unit is tilted at 45 degrees in any direction or whenever someone has been using it for more than 20 minutes continuously, in order to avoid mild malfunctions or certain accidents.

In order to protect this device and to ensure its durability for long-term use, you need to perform a maintenance routine before you prepare it for extended storage. You only need to make sure all the water inside has been drained and the heater is empty, in order to protect its coils.



This model’s design features are radically different from the L10 alternative that was issued by the same brand. It comes with two knobs for easy adjustments and a handle to help the customer change the position of this device and install it wherever they need to.

It is rated at 1.5 GPM according to the hot water output that it can provide, a bit less than its counterpart. However, it can achieve a range of temperatures between 50 and 140F, which is again very similar to the L10.

Also, a nice design feature that some users might enjoy is that it automatically turns on when it senses water flowing through. It will run continuously for 20 minutes and then shut off due to safety reasons.


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