The RV lifestyle is hard to beat—what could be better than cruising around the country in a decked-out mobile home while exploring remote wilderness regions of unfathomable beauty? But life on the road isn’t always luxurious: no matter how you spin it, you’re still camping. Yet for those with the means to invest, there are ways to make the RVing experience more comfortable, lighter weight, and energy-efficient. And one of the most comforting things to have on a road trip is an unlimited supply of piping hot water.
That’s where the RV tankless water heater comes in, a high-tech device with the power to produce gallon after gallon of steamy hot water instantaneously. Also known as an on-demand water heater or instant water heater, these miraculous machines give you a nice hot shower anywhere you want, for as long as you want.
Today we’re going to examine the best RV tankless water heaters on the market and provide vital background info in our in-depth RV Tankless Water Heater Buyer’s Guide.

Features to Consider
Before we get stuck into our top ten list, there are several things you need to consider. The best RV tankless water heater for you ultimately depends on your budget, heating requirements, and existing RV setup. Take the following considerations into account before hitting the ‘buy now’ button.
Size
There’s no point buying a tankless water heater that doesn’t fit in your RV—the only thing you’ll achieve is wasting your hard-earned cash. And even though tankless systems tend to be quite small, your preferred model won’t necessarily fit where you need it.
Break out your measuring tape to determine the maximum possible dimensions your brand new system could be. And if you’re not sure where you’re supposed to install it, then you best get the help of a professional first.
Type
RV tankless water heaters come in three different types: gas, electric, or a combination of the two.
Electric models are cheaper to run as you can power them via solar and batteries (if you’ve got an advanced setup) or by plugging them into the shore power.
Gas models (either propane or LPG) are better for boondocks as they don’t suck up limited electrical power when used off-grid.
Combo heaters offer the best of both worlds but are a bit more expensive to buy and install—in some cases, you won’t be able to install them at all.
Furthermore, some of the models we recommend are portable, which means you can quickly assemble them wherever you wish. Fixed water heaters, on the other hand, are more expensive and need to be permanently installed inside the RV, although these perform much better than portable units.
Finally, some tankless water heaters are point-of-use (POU), which means they’re only capable of heating one specific faucet at a time.
Flow Rate
The flow rate refers to how much hot water you can pump out of the machine, which is measured in an easy-to-understand unit called Gallons Per Minute (GPM). There’s no point buying a tankless heater with a GPM that greatly exceeds your real-world requirements, as you’d be paying a premium for something you don’t need.
Consequently, you should work out how many gallons per minute of hot water you and your whole traveling crew might use. For starters, most showers run between 1.5 and 3 gallons per minute. However, if someone else wants to do the dishes at the same time, you’d need to add another 1.5 GPM to heat the sink faucet as well. Keep in mind that you’re not only limited by the flow rate, but by the water storage capacity of the RV itself.
British Thermal Units
British Thermal Units (BTUs) refer to the speed at which the tankless water system works and how hot the water will get.
If you do most of your RVing in colder climates where having access to piping hot water is a must, then aim high. Conversely, summertime RVers or those who roam around our warmer southern states might get away with something less powerful.
As a ballpark figure, RV tankless water heaters typically range between 30,000 and 50,000 BTUs. Although some portable models are rated higher, their lower flow rates equate to inferior performance overall.
Price
Price is always an important consideration when upgrading your RV as parts and installation are never particularly cheap. And with RV tankless water heaters ranging from $150 to $1,500, the difference between the premium and economy models is an order of magnitude. If you live in your RV full-time, then it makes sense to fork out for a top-shelf model; on the other hand, if you’re a weekend warrior, it’s probably okay to get a cheap, less powerful unit.
Note that electric heaters are more expensive upfront but cost less to run (you’ll be using them off your solar/battery system or the pre-paid shore power at the RV park). Gas heaters are cheaper to buy, but you’ll have to keep topping up your propane tanks, which requires money and effort.

Top 10 Best RV Tankless Water Heaters 2020

1. Best Overall RV Tankless Water Heater: Girard 2GWHAM

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Why we like it: This high-performance propane unit is specially built for RV use and will pump out plenty of piping hot water in a jiffy.
Editor’s Rating:

Quick Facts:
Heater Type: Propane / fixed / non-POU
Flow Rate: Minimum of 2.5 GPM
BTU: 42,000
Weight: 21.2 pounds
Dimensions: 14.5 x 17.8 x 14.6 inches
Despite plenty of fierce competition, among our favorites is the Girard GSWH-2, one of the best RV tankless water heaters available today. Unlike some of the other options we’ll cover, this model has been specially designed for RV use, so you can expect the 42,000 BTU heater to work consistently with minimal fuss.
Part of the magic is the onboard microchip that automatically detects large volumes of cold water and analyzes the flow rate to give the happy camper a hot shower every time. Another nifty high-tech feature is the wall-mounted digital control that lets you pre-program any temperature you like between 95°F to 124°F—perfect for parents with little kids in tow.
A big plus for those living in the colder northern states is the heater comes winterized,  automatically preventing the heat exchange from freezing up and self-destructing. If you’ve spent any time RVing in subzero temperatures, you’ll know how important that can be. Plus, because the ignition works on your 12V system, it’s brilliant for using off-grid so you won’t have to seek out an RV park every time you want a good soak.
It may cost a bit more than some of its competitors, but the investment is well worth it for serious RVers, especially those living in their rigs full time. Be aware, however, that the manufacturer insists on a professional installation, which you’ll need to factor into your budget. If you’re especially handy with the tools and have the help of a licensed gas fitter, you may be able to get it installed DIY, but given how dangerous a gas leak can be, you’re probably better off with their recommendation of a professional.

Pros

Computer chip controlled temperature adjustments
Wall-mounted display screen
Pre-programmable temperature settings
Long hot showers aplenty
Winterized

Cons

More expensive than other units
Requires professional installation

2. Best Electric RV Tankless Water Heater: Stiebel Eltron DHC

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Why we like it: Stiebel Eltron heaters work wonderfully well and come in a wide array of models to suit differing power capacities.
Editor’s Rating:

Quick Facts:
Heater Type: Electric / fixed / POU
Flow Rate: 0.79 GPM
Weight: 6.6 pounds
Dimensions: 19 x 7.9 x 14.25 inches
Stiebel Eltron has been producing superb single-point-of-use water heaters from their Berlin factory since the 1920s, so you can rest assured they’ve got it worked out—nothing but high-quality German engineering here. Their DHC model is perfect for intrepid nomads living out of their RV.
With a wattage rating between 7200 and 9600W, the unit is far too power-hungry to use off-grid, so you’ll need to be prepared to shower in the RV park. But if you’re the kind of RVer who spends most of the time connected to the mains, it’s a simple and easy solution for everlasting long showers. Unlike propane, you’ll never have to refill the tank, making it a no-fuss solution for anyone living in an RV park long-term. And at under $200 a pop, going electric is the cheapest way to getting consistent hot water when you need it.
Do note, of course, that these units are single-point-of-use only, which means you’ll only be able to connect it to one faucet (you’ll have to clean the dishes with cold water or buy a separate sink-only system like the Ecosmart POU).
The hydraulically controlled unit runs quietly, and its resettable safety limit switch stops it from failing prematurely or dry firing, thus enhancing the longevity of the machine. Temperature control is easy via the user-friendly dial, although you’ll need to run it at low water pressure for a scalding hot shower.

Pros

Runs wonderfully of the mains power
No need to refill propane bottles
Quiet and reliable
Safety limit switch prevents dry firing
Cost-effective water heating solution

Cons

POU
Only works well on low water pressure

3. Best Budget RV Tankless Water Heater: Marey GA10LP Tankless Water Heater

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Why we like it: This compact and cost-effective propane-powered unit spurts out a steady 3 gallons of steamy hot water per minute.
Editor’s Rating:

Quick Facts:
Heater Type: Propane / fixed / non-POU
Fixed or Portable: Fixed
Flow Rate: 3.1 GPM
Weight: 21 pounds
Dimensions: 6.9 x 13.6 x 23.6 inches
Budget-minded RVers can find it challenging to get a reliable tankless water heater within their price range. Spend too little, and you’ll likely end up with a lemon that barely gets the job done, too much, and you won’t have any money left over for those other essential upgrades you’ve got your eye on.
That’s what we love about the Marey GA10LP—despite its low price point, the unit manages to pump out enough hot water for a comfortable shower or to wash that mountain of dirty dishes.
Although it isn’t specially designed for RV use, the beefy system works well in your mobile home, and the fact it’s super slim is a massive bonus for the owners of smaller RVs with minimal space. The flow rate is quite impressive when you consider the tiny dimensions of the unit. Case in point: its 3.1 GPM is enough to heat multiple points of use at the same time, so you can throw on a load of laundry while a travel partner hops in the shower.
The ignition system runs on 2 D-cell batteries. Although you’ll need to buy them yourself, you won’t have to worry about having enough juice in your house batteries to get the unit started up.
Temperature control takes a bit of fiddling to get right, which is hardly surprising for a unit at this price point. The biggest downside, however, is you’ll need to pump through a lot of cold water before it’s warm enough to shower. If you’re plugged into the RV park water supply, then that’s no big deal. But if you’re boondocking off the grid, you’ll quickly start to miss those precious wasted gallons.
On the bright side, in the rare event of a breakdown, Marey has got your back with their 5-year warranty.

Pros

Cost-effective solution
Powerful enough for multiple usage points
Small and compact to install in a tight space
Impressive 3.1 GPM flow rate
5-year warranty

Cons

Can be tricky to adjust to the right temperature
Takes a while to heat up, leading to wasted water
Need to purchase pilot light batteries separately

4. Best Premium RV Tankless Water Heater: PrecisionTemp RV-550 – Wall Vented

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Why we like it: Endless hot showers make this chunky unit well worth the hefty price tag for full-time RVers.
Editor’s Rating:

Quick Facts:
Heater Type: Combo / fixed / non-POU
Flow Rate: Minimum 0.5 GPM / optimal operation 1.0 GPM
BTU: 55,000
Weight: 32 pounds
Dimensions: 13.5 inches x 13.5 inches x 14.25 inches
Full-time RVers who frequent cold environs are constantly on the lookout for ways to obtain the holy grail of luxury mobile living: a long, steamy shower when it’s freezing out. And even though this pricey system from PrecisionTemp comes in at well over a grand, that’s money well spent for travelers tired of taking those frustratingly short navy showers.
Pumping out a whopping 55,000 BTUs, the RV-550 is among the best performing RV heaters on the market. Expect endless streams of piping hot water to finally become the norm—you can even run two hot showers at the same time with that kind of output.
As you’d expect at this price range, the system comes with all the technological bells and whistles to make temperature control a breeze. The in-built VariFlame system automatically adjusts the gas output based on the water flow, so you won’t have to keep fiddling with the faucet to find the ideal temperature. It’s ultra-energy-efficient, too, which means fewer tiresome trips to the gas refiller to top up your propane tank. Northerners will be happy to hear the system can quickly and easily be winterized.
Although installation isn’t something the layman would want to tackle, there are plenty of helpful YouTube videos and online tutorials to guide a skilled handyman through the process. Just be sure to get a gas fitter to certify the setup once you’re done. And if you have any trouble further down the track, PrecisionTemp has a well-earned rep for delivering quality customer service over the phone.

Pros

Endless hot showers
Consistent water temperature
Reliable, high-quality design
Capable of running two showers at once
Excellent customer service

Cons

High price

5. Best Portable Tankless RV Water Heater: Eccotemp L10

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Why we like it: The Eccotemp L10 outperforms the other portable tankless water heaters on the market.
Editor’s Rating:

Quick Facts:
Heater Type: Propane / portable / POU
Flow Rate: 2.6 GPM
BTU: 74,500
Weight: 27 pounds
Dimensions: 5.37 x 1.97 x 88.78 inches
Portable water heaters are a blessing for folks with small RVs who just don’t have the room to install a fixed shower in their rig. The L10 from Eccotemp is the best of the bunch, providing a nice warm shower sans the time-consuming, permanent setup.
The user-friendly unit maxes out at 74,500 BTU to heat 50-degree water to 140F—but don’t expect the same consistency as a fully installed tankless heater like the PrecisionTemp RV-550 – Wall Vented.
Almost all users opt to set the unit up outside their RV, and the L10 goes from unpacked to ready to roll in a matter of minutes. Hang it up, connect it to your 20lb propane tank, connect the water outlet and inlet, and you’re ready to enjoy instant hot water in the wilderness. Granted, it’s a bit more involved to set up than a fixed heater, but getting things rolling is about as easy as it can be with a portable heater.
Two D cell batteries power the ignition switch, and the system runs wonderfully with a 12V pump. Should you forget to turn the unit off, an automatic 20-minute shut off function ensures you don’t waste your precious propane. The system is not exceptionally efficient, so expect to burn through gas at a quick rate.
Some of the connectors and adapters are prone to breaking, although these can be cheaply replaced at your local hardware store. Remember to drain the unit entirely before the outside temperature hits freezing, otherwise you can permanently break the heating element and have to pony up for a new one.

Pros

Cost-effective
Easier to assemble than most portables
Lightweight and compact
High-powered heating

Cons

Inconsistent water temperature
Uses a lot of propane
Some parts prone to breaking

6. Camplux Outdoor Portable Propane Tankless Water Heater

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Why we like it: It’s a fantastic alternative to the Eccotemp L10 for RVers after a portable outdoor water heater.
Editor’s Rating:

Quick Facts:
Heater Type: Propane / portable / POU
Flow Rate: 1.32
Weight: 14 pounds
Dimensions: 11.42 x 4.33 x 14.8 inches
As you’ve probably gathered from the name, Camplux builds a range of high-quality equipment to make the camping life that little bit more luxurious—and that encompasses those living or traveling in an RV. The petite yet powerful portable water heater is light enough to carry around with you and pumps out a respectable 1.32 GPM of lovely 114F degree water.
Granted, it’s not going to compete with a dedicated hot water system. Still, the cost-effective solution is simple to set up and among the best performing portable options out there. And unlike other portable heaters, the Camplux has a shut-off protection system for when oxygen levels drop too low, thus winning it top marks for safety. Do remember, though, that this and other portable systems are strictly for outdoor use only (CO2 output isn’t something to mess around with).
We love the easy operation of this model. Simply set your preferred temperature and turn on the tap to get the desired water flow—the automated system will do the rest, so there’s no need to turn on the pilot light. Be careful not to adjust the gas dial too far past the mid-point, however, as that seems to set the water temperature to a scalding, burn-your-skin level of heat (we’re not quite sure who’d want a shower like that).
Assembly is easy and doesn’t require any advanced technical knowledge. Do pay attention to the instructions, though, as you need to do everything in the correct order to get the heater functioning properly.

Pros

Lightweight and portable
Low oxygen level safety shut off
Easy to assemble and use
Cost-effective solution

Cons

Anything past the mid-way point is way too hot
Can’t compete with fixed systems

7. Best Infrared RV Tankless Water Heater: Sio Green IR288

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Why we like it: State of the art infrared technology saves you stacks of cash on replacement and maintenance costs.
Editor’s Rating:

Quick Facts:
Heater Type: Infrared electric / fixed / non-POU
Flow Rate: 0.5 to 4.5 GPM
Weight: 10.21 pounds
Dimensions: 13.5 inches x8.5 inches x3 inches
One of the big drawbacks to electric heaters is that their metallic coil heating elements are prone to corrosion and will eventually need replacement. No matter how well you look after your system, limescale and calcium deposits will accumulate and eventually ruin the heating coil. On top of that, the fact that fixing the heater isn’t particularly user-friendly means forking out for a professional repairman on top of the replacement part can cost you.
But that’s where infrared technology comes in, which creates heat without water ever coming into contact with a metallic coil. This way, you won’t have to replace the element, saving serious coin on maintenance costs. Of course, all this newfangled technology results in a higher upfront investment than your standard electric heater. But if you plan to use it for many years to come, the system will work out cheaper in the long run, and you’ll enjoy lovely hot showers every time.
This high-performance model maxes out at 9,000 W, which is way too much to use off-grid. If you’re looking for an infrared tankless water heater you can use with a solar system or generator, consider the more modest [amazon url=”https://www.amazon.com/dp/B07RC454N5″]3,400 W[/amazon] or [amazon url=”https://www.amazon.com/dp/B07SFY6SCV”]6,000 W[/amazon] model instead.
Temperature control is a little challenging as the unit can only be set in Celsius. Nonetheless, after a few confusing calculations, you’ll quickly get the hang of the different units.

Pros

Doesn’t use a heating coil which reduces maintenance costs
Delivers reliable hot water without the need for propane
Comes in a range of wattages

Cons

Isn’t suitable for off-grid use (although lower-powered models are available)
Temperature control is in Celsius

8. EZ 101 Tankless Water Heater

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Why we like it: EZ does a decent, ultra-light outdoor shower for when there’s no electricity available.
Editor’s Rating:

Quick Facts:
Heater Type: LPG / portable / POU
Flow Rate: 1.58 GPM
BTU: 42,500
Weight: 14 pounds
Dimensions: 7 x 17.5 x 11.8
RV enthusiasts who don’t want to rely on their 120V or 12V system to spark up the water heater might consider the 101 from EZ, which uses 2 D cell batteries to ignite the propane. That way, if there’s a blackout or if cloudy weather renders your solar panels ineffective, you’ve still got the chance to enjoy a nice hot shower to finish off the day.
Having said that, the first thing you need to consider about this model is that, like other portable heaters, it’s rated for outdoor use only. Hanging the 101 up inside your RV could be dangerous if the gas tank leaks when you’re sleeping. That’s a very strong reason why the manufacturer specifically says “not for indoor use.”
Still, if you’re happy to set the system up in the great outdoors, then it’s a pretty nifty portable product. Although the Eccotemp L10 performs better, the 101 is lighter, therefore easier to lug around. If you want something you can transfer between the barnyard, the RV, and the workshop with ease, the EZ 101 is the best option for you.

Pros

No electricity required
Lightweight and portable
Suitable for moving between RV and other areas

Cons

Less effective than other portable water heaters
Cannot safely be used inside

9. Best RV Tankless Water Heater For The Sink: Ecosmart POU

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Why we like it: A super cheap POU solution for when showering isn’t the aim of the game.
Editor’s Rating:

Quick Facts:
Heater Type: Electric
Flow Rate: 0.5 GPM
Weight: 4 pounds
Dimensions: 3 x 11 x 6 inches
You’ve probably noticed in our reviews that we use the coveted hot shower as the benchmark to determine whether a hot water system delivers the goods. But what if you’re not interested in hot showers at all? What if all you need is something to heat the sink water enough to scrub those stubborn ketchup stains off your endless pile of dirty dishes?
If that’s you, then grabbing the low-powered Ecosmart POU will save you a ton of cash. The meager 0.5 GPM flow rate means the unit isn’t powerful enough to deliver a full-flow shower, but it’s easily sufficient for the sink. Its low amperage draw and wattage rating saves money upfront and drains your RV house batteries way less than a more powerful system (off-grid camping won’t be a problem with this bad boy). The compact unit even has a handy digital display so you can set the temperature.
If you’ve already got a POU system installed in the shower, then setting this cost-effective and straightforward model up in the sink is all you need.

Pros

Cheap to buy
Draws very little electricity
Perfect for the kitchen sink

Cons

Can’t heat a shower up

10. Eccotemp i12-LP

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Why we like it: The i12-LP is a respectable alternative for folks after a portable Eccotemp system.
Editor’s Rating:

Quick Facts:
Heater Type: Propane / fixed / POU
Flow Rate: 4 GPM
Weight: 14.08 pounds
Dimensions: 11.42 x 4.33 x 14.8 inches
Eccotemp produces some of the finest portable tankless water heaters on the market, earning a reputation for excellence among the outdoorsy camping crowd. Although their fixed hot water systems aren’t quite as highly lauded, this i12-LP model does a respectable job at creating quick hot water without chewing through too much propane.
Another nifty plus is its high-tech LED display, which looks sleek and state-of-the-art while hanging in your ensuite wall. Automatic temperature controls ensure the water never gets too hot, and a child-lock system stops the little ones from messing with the settings.
The system plugs into a 110V system, so you’ll need to run it off an inverter if you hope to enjoy hot water off-grid. Installation can be a bit of a hassle, so it’s best to get a professional involved. The good news is the system is cheaper than most other fixed tankless heaters, which leaves you more room in the budget for installation.
The bottom line? If you’re after a low-budget fixed propane system, then the i12-LP is well worth considering. But if you’ve got a bit of extra cash, you can’t go past the propane-powered perfection of the Girard 2GWHAM.

Pros

Handy LED display
Automatic temperature control
Child-proof lock
Requires professional installation
Cost-effective

Cons

Doesn’t perform as well as other fixed systems

Shopping for an RV Tankless Water Heater
RV tankless water heaters are a significant investment, and the last thing you want to do is blow your hard-earned dosh on a model that doesn’t suit your needs.
We’ve put together this in-depth buyer’s guide to provide you with essential background information on the world of RV tankless water heaters. Read on to learn everything you need to know to find the perfect product for you.
What Is An RV Tankless Water Heater?
Let’s start with the basics, shall we? An RV tankless water heater is exactly as it sounds: a water heater that doesn’t use a tank and is compatible with—or specially created for—an RV.
Some folks refer to these as on-demand water heaters or instant water heaters: same thing, different name.
RV Tankless Water Heaters Versus Tank-Based Water Heaters
Tankless water heaters use either a gas or electrical heating element (or both simultaneously) to heat water the moment it passes through the system. As a result, you get a steady stream of piping hot water coming out of your shower, faucet, or washing machine without having to wait around for the whole tank to heat up.
Compare this to a tank-based water heater, which heats a whole tank full of water before delivering it to your faucet. These older and less desirable systems take several minutes to warm enough water, and the hot water tank tends to cool down with intermittent use. As a result, although they may be cheaper, tank-based systems fail to provide a consistent supply of hot water when you need it and use much more energy.
RV Tankless Water Heater Types: Electric, Gas, or Combo?
RV tankless water systems run on gas (LPG or propane), electricity, or a combination of the two.
Electric RV Tankless Water Heaters
Electric tankless water heaters are a viable option as they’re eco-friendly and cost-effective to run. The heaters work on the 120V system of your RV, so if you’re planning to use your water heater off-grid, you’ll need to ensure your converter is capable of handling the required wattage. You’ll need an expensive solar and battery set up to reap the benefits of an electric tankless water heater off the grid, but the expense is well worth the reward for van-lifers and full-time RVers. If you’ve installed a full electric system, it’s worth it to take a look at electric trailer jacks as well.
Once it’s set up, you won’t pay a cent because you’ll be using the energy from your alternator or your solar panels as you drive. And when you’re plugged into the shore power at the RV park, you won’t have to pay either because electricity is already included in your nightly rate.
With gas-powered models, on the other hand, you’ll continuously have to pay to refill the tank, which is also a bit of a hassle depending on how remote you are when the cylinder runs out.
The downside is cost. Although electric tankless water heaters can be cheap to purchase and install, you’ll need a large-capacity battery bank, solar panels, and inverter set up should you wish to run it off the grid.
Gas-Powered RV Tankless Water Heaters
Gas-powered RV tankless water heaters use either propane or LPG to heat the element rather than electricity. As you know, both these energy sources are highly efficient, which is why gas-powered water heaters can offer a superior number of BTUs than electric models. Put simply, gas-powered tankless water heaters work harder and perform better. And as a nifty little bonus, the system type is simple and cost-effective to use off the grid.
On the downside—there’s always a downside—gas is a finite resource that can’t be harnessed from the sun or your engine while you drive. You’ll have to fill your propane/LPG tanks manually, which costs money and can be a non-option when there’s no major town within a hundred-mile drive. Worse still, you could run out of gas the moment you hop in the shower or turn on your stove. In that case, you would have to do without until you can find someone to refill your tank.
Note that gas-powered heaters require stainless steel flues to the exterior and need regular maintenance from a licensed gas-fitter to ensure everything is in working order. LPG and propane are deadly if not properly managed, so you need to take the proper installation seriously.
Combo RV Tankless Water Heaters
What if I told you that you could incorporate the best of both energy sources into the one high-tech design? Well, you can, and they’re colloquially known as combo RV tankless water heaters. These systems are the ultimate RV solution as they can draw on both your gas and electricity supply to give you a wonderfully warm shower whether you’re on or off the grid.
In normal circumstances, they use both resources simultaneously to heat water as it passes through the system. But should your batteries start running low, or your propane tank begins to dwindle, it switches over to the more abundant energy source so you can keep enjoying hot water for many days to come. Consequently, they’re the hot water system of choice for the intrepid RVer who loves boondocking in remote and wild locales.
As you’d expect, these cost substantially more than the two aforementioned systems because they incorporate two separate heating technologies into the one design.
RV Tankless Water Heater Types
Now that you understand the difference between gas and electric water heaters, it’s time to consider whether a portable or fixed unit is best for your needs.
Fixed RV Tankless Water Heaters
Fixed RV tankless water heaters are permanently installed in your rig. A fixed system will require a series of vents or flues to ensure gas flows safely into the outside air and dissipates in the atmosphere. Installing these vents, should you not already have them, can be a challenging and expensive task that may involve taking an angle grinder to the wall of your RV.
The big benefit of the fixed system is it outperforms portable water heaters by several orders of magnitude. And because you’ve got the appropriate ventilation flues in place, they’re safe to use inside the rig.
Portable RV Tankless Water Heaters
Portable water heaters aren’t explicitly designed for RV use, although they can indeed be used by folks traveling in a mobile home. The system attaches directly to a propane tank, so it doesn’t require installation and can be lugged around for use anywhere in the great outdoors.
As portable systems aren’t vented to the outside, it’s perilous to use these inside the RV. As a result, you’ll have to carry the system outside to use it safely in the open air every time you need to shower. Most people purchase a separate [amazon url=”https://www.amazon.com/dp/B078WFWRPX”]tent ensuite[/amazon] to ward off prying eyes.
Portable tankless water heaters are way cheaper than fixed systems but are much less convenient to use.
Condensing Versus Non-Condensing Tankless Water Heaters
Regardless of the type of tankless water heater you’ve got in your RV, it can also be either condensing or non-condensing.
Condensing heaters are more efficient because they recycle the heat from the exhaust to warm your water, thus requiring less energy. Non-condensing heaters don’t do this and are less efficient as a result, although they’re more reliable for their simplistic design.
Infrared Water Heaters
Some electricity-based tankless heaters like the Sio Green use infrared technology to heat up water without the heating element actually coming into contact with the water. These heaters are energy efficient and can go for years without requiring replacement parts, although they suffer from the same off-grid drawbacks as other electric water heaters.
Point of Use (POU) RV Tankless Water Heaters
Some RV tankless water heaters are ‘point of use’ (POU), which means they only heat one specific faucet and can’t be used for multiple water sources. All portable water heaters, for example, are POU as they’re specially designed to heat the water flowing through the attached showerhead.
Fixed systems usually aren’t POU, therefore, they can heat water to multiple faucets at once.
If you just need hot water in your sink, then look for a low powered POU unit like the Ecosmart POU as you’ll save money upfront and burn through less propane.
The Benefits of Using an RV Tankless Water Heater
Now that you’ve got the basics of what a tankless water heater is, it’s time to delve into the details of why these systems are superior to the tanked-based variety.
Efficiency
Tankless water heaters are far more efficient than tank-based systems for one simple reason: they only heat the water you need when you need it. Tank-based systems will warm up gallons of water even if you only want a tiny squirt to do your dishes, resulting in a substantial sum of unnecessary energy expenditure. And when you’re living off-grid and need to conserve all the energy you can, that just doesn’t cut it.
Speed and Consistency
Rather than waiting around for the whole tank to warm, tankless water heaters heat the liquid as it passes through the system via a pump, thus allowing hot water to arrive at the faucet in an instant. When you’re cold and want to jump into a soothing hot shower straight away, it’s a godsend to have a tankless water heater ready to roll in your rig.
Another great plus with the tankless design is consistency. As these systems heat the water as it passes through the element, you’ll get to enjoy a lovely long shower session without those annoying cold spurts jutting in halfway.
Temperature Control
Some of the more upmarket tankless water heaters such as the Girard 2GWHAM come with digital control panels that allow you to predetermine the perfect temperature, so no more fiddling around with the shower knob.
Small and Lightweight
By their very nature, tank-based water heaters are bigger and heavier than tankless systems—you have to make room for the hot water tank, after all. Given space is a sought-after necessity in every home on wheels, it’s always a big bonus to buy the smallest components you can. In many setups, you might not have room to install a tank-based water heater at all, making tankless your only option.
Tankless heaters are not only smaller, they’re also lighter. As you know, the less weight you’re hauling on your RV, the less fuel you’ll burn through. Optimizing your miles per gallon is a significant consideration of every budget-conscious RVer, and going with a lighter hot water system will save you money in the long run.
Eco-Friendly
With a tank-based water system, you’ll stand around waiting for the water to heat up as gallons of the good stuff flow wastefully down the drain. With a tankless hot water system, however, you can jump straight into the shower within moments of turning it on and enjoy piping hot water in an instant. No more wasting water while you wait for it to become hot enough to wash in.
Water is a precious resource in the real world. But for the RVer with a finite freshwater tank below the chassis, it’s more than just precious—it’s indispensable.
Endless Hot Water
To be fair, if you’re boondocking, you still only have as much hot water as your freshwater tank permits. However, if you’re hooked up to a water/electric supply at an RV park, you could shower for hours in steamy hot water just like you do at home. And for RVers who’ve recently come back from an especially grueling hike through a dusty backcountry trail, an extended shower session is just what the doctor ordered.
With the tank-based system, on the other hand, you can only shower for as long as the hot water tank lasts, typically less than 10 minutes.
Long-Lasting Design
While traditional tank-based water systems can generally last somewhere between five and ten years, the newer and durable tankless water heaters are good to go for a decade or more with proper maintenance and care. In fact, some manufacturers claim a useable life of up to two decades.
The Drawbacks of Using an RV Tankless Water Heater
So if tankless water heaters are such a wondrous thing to have in an RV, why isn’t everyone using them? Who in their right mind would settle for the inferior tank-based system?
There’s one major caveat to a tankless water system: cost. Tankless systems have more advanced heating elements and parts, meaning they’re more expensive to purchase outright. Furthermore, these systems sometimes require expensive flues and vents to the exterior of the vehicle, which is pricey to install if you don’t have already a flue place.
But for RVers who are willing to splash out on optimizing their mobile home, the tankless water system is a sound investment.
FAQ
Any more questions? There’s a good chance we’ve answered them below.
Can I Convert from a Tank-Based RV Water Heater to a Tankless One?
It’s certainly possible, but the complexity of the operation will depend on what system you’ve currently got versus the system you want. As you’d expect, it’s much easier to go from tank to tankless by using the same power source, either electricity or gas. Switching between the two requires a significant overhaul that will set you back stacks of cash.
Don’t try installing a gas-powered water heater (or anything else for that matter) yourself unless you’re a licensed gas-fitter, or you can get one to look over your work. Doing so may well be illegal in your state, and one wrong move could result in a deadly gas leak.
Can I Install an RV Tankless Water Heater Under the Sink?
Most of the time, yes: although it’s common to install water heaters under the sink, that doesn’t necessarily mean it’ll always be possible. Download and read up on the instruction manual of the unit you want to buy to see if it’s possible. Alternatively, seek advice from a professional installer.
Does Every Tankless Water Heater Require an Electrical Connection?
No, but most do. Many gas-powered tankless water heaters require an electrical connection to power the pilot light. Some, however, use a battery for this process, thus removing the need to be hooked up to a shore-powered electrical system. The most common batteries for pilot lights are 2x D cell batteries, which are widely available around the country and easy to replace.
Do I Have To Clean an RV Tankless Water System?
All hot water systems—regardless of whether they’ve got a tank or not—need to be cleaned regularly to ensure the water passing through remains potable. Generally speaking, every 6-12 months is an acceptable timeframe, although it’s wise to check the instruction manual for specifics. The manual will also tell you how to clean and maintain the system.
The Best Tankless Water Heaters: The Final Verdict
Enjoying a long hot shower is a blessing when you’re living in an RV, so it makes sense to invest in the best possible water heater you can afford. Tankless heaters provide piping hot water in an instant and never run out halfway through the deed.
We’ve covered the top 10 RV tankless water systems available on the market, with various options to suit different budgets and usage requirements. Take a gander through our list to pinpoint the ideal hot water solution for you.
Once you’ve found the perfect option, you’ll wonder how you ever got by without consistent, energy-efficient hot water. More

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