Our Top Picks
- Self-modulating technology
- Easy-to-use digital thermostat
- Under 12 inches tall
- 66,000 BTU, up to 3.6 GPM
- Remote control and mixing tank
- Fits a standard 6-gallon tank opening
- Produces 1.3 gallons per minute
- 0.99 energy factor
- Whisper quiet
- Attractive blue finish
- Self-modulating technology
- Compact 17 inch height
- Off-grid camping with propane
- Large handle for hanging or moving
- Includes most required equipment
Our Review Criteria: Fit rules the RV category: a tankless heater must slide into a standard tank bay before any other spec earns consideration. We then compared flow rate and BTU output, fuel and power requirements, and how each unit handles altitude and cold inlet water. We checked manufacturers’ published figures against verified owner feedback and looked for CSA certification. We confirm every pick is currently sold and in stock and swap out any model that goes out of production.
A 6-gallon RV tank gives you a few minutes of hot water, then the next person in line showers cold. A tankless unit heats water as it flows, so everyone at the campsite gets a warm rinse, even on a busy weekend with the whole family aboard.
The catch is that RV tankless heaters vary a lot in flow rate, fuel type, and how they handle cold inlet water, and a unit that works at a full hookup site can sputter when you boondock.
This guide walks through how to choose one, the types worth considering, and our picks of the top models, judged on flow rate, temperature control, cold-weather performance, and how easily they swap into an existing rig.
How to Choose an RV Tankless Water Heater
A tankless water heater is a massive upgrade for any rig. They connect to your onboard plumbing to provide hot water on demand. Before you dive into the reviews, here is what you need to know.
Types of RV Tankless Water Heaters
You also need to decide on the form factor. Do you want a permanent install or something you can move around?
Portable
A portable tankless water heater is usually hung outside the RV or on a tree. These are popular with teardrop campers, van lifers, and tent campers who want an outdoor shower.
Pros
- Versatile: You can set it up anywhere. Many come with a showerhead attachment included.
- Easy Setup: No cutting holes in your RV wall. Just hook up a propane tank and a garden hose.
- Affordable: These are significantly cheaper than installed systems.
Cons
- Outdoor Only: Most portable units are not vented, meaning you cannot use them inside the RV safely due to carbon monoxide risks.
Installed (Whole-RV Systems)
This replaces your existing 6-gallon tank heater. It mounts permanently into the sidewall of your RV. If you want a residential experience where you just turn the knob and get hot water, this is the way to go.
Pros
- High Performance: Designed to handle the water pressure and demand of a full RV plumbing system.
- Convenience: Works exactly like a home water heater. Many come with digital wall controllers to set the precise temperature.
Cons
- Complex Installation: Requires plumbing, gas line work, and 12V electrical wiring. You might need a professional installer.
Product Reviews
We analyzed flow rates, power requirements, and durability to find the top units for your rig. Here are our five favorite RV tankless water heaters.
EcoSmart 8 KW Electric Tankless Water Heater
Best Tankless Water Heater for Eco-Friendly Camping
Spending time in your RV is about enjoying nature, so an eco-friendly electric heater makes sense. The EcoSmart 8 KW is a powerful electric option that eliminates the need for propane.
The smart self-modulation is the draw: it adjusts energy input to exactly how much hot water you are pulling, which curbs energy spikes and wasted electricity. A digital control lets you set the temperature in 1-degree steps, and the footprint is tiny at 12 by 8 inches, so it tucks into a cabinet or storage bay.
It is a residential point-of-use heater at heart, but it does the job in RVs with the electrical headroom to feed it, heating about 1.5 GPM to 105 degrees Fahrenheit. Remember it is electric and draws real amperage on a 40-amp double-pole breaker, so confirm your campsite hookups can carry the load.
What We Like
Smart Self-Modulation
This unit is brilliant at energy management. It only draws the power necessary to heat the water flowing through it. If you only turn the tap on halfway, it uses less electricity.
It also features durable copper and stainless steel components that resist corrosion, which is vital for longevity.
Digital Precision
The external digital thermostat allows for 1-degree adjustments. You can set it to the exact temperature you like for a shower without having to mix in a bunch of cold water.
Space-Saving Size
This EcoSmart model saves serious room. It is only about the size of a standard sheet of paper and less than 4 inches deep. This frees up valuable storage space compared to a bulky 6-gallon tank.
Note that this requires a 40-amp double pole breaker. You need a 50-amp RV service to run this safely alongside other appliances.
What We Don't Like
Struggles in Freezing Weather
Electric heaters rely on groundwater temperature. If the incoming water is near freezing (below 45 degrees F), the unit works much harder and the flow rate drops off. It performs best where the inlet water sits around 57 degrees F or warmer.
Warranty Has Strings Attached
The limited lifetime warranty only stands if a licensed electrician and plumber install the unit and you register it within 30 days of receipt. A DIY install voids it, so budget for a pro if that coverage matters to you.
Product Specs
| Measurements | 11.5 inches by 8 inches by 3.75 inches |
|---|---|
| Flow rate | 1.5 gallons per minute |
| Temperature range | 80 to 140 degrees Fahrenheit |
| Weight | 5.3 pounds |
| Warranty | Limited lifetime warranty |
Fogatti InstaShower 9 Pro RV Tankless Water Heater
Best Tankless Water Heater for High-Tech RV's
If your rig runs on propane and you want the most hot water for the space, the Fogatti InstaShower 9 Pro is the high-tech pick. This Gen 3 RV tankless unit puts out 66,000 BTU and up to 3.6 GPM, enough to run the shower and the galley sink at once.
A wired remote controller sets the temperature to within one degree from inside the coach, and a built-in mixing tank smooths out the swings that plague basic RV tankless units. It drops into a standard 15 by 15 inch opening, replacing a Suburban or Atwood 6 gallon tank without cutting new holes.
What We Like
Remote Temperature Control
The included remote lets you set the output to the degree without crawling into a storage bay. With plus or minus one degree accuracy, you get the same temperature whether you are rinsing dishes or taking a shower.
Built-In Mixing Tank
Older RV tankless units send a cold burst when you pause the water, the so-called cold water sandwich. The mixing tank buffers that, so a quick shut-off and restart at the showerhead stays warm.
Runs at Altitude
Fogatti rates this unit to work up to 9,800 feet, so it keeps heating on mountain trips where weaker burners stall. It is CSA certified and ships with a 150 PSI pressure relief valve already installed.
What We Don't Like
Propane and Venting Required
This is a gas unit, so it needs an LP supply and proper sidewall venting. It is not a plug-in electric heater you can run off shore power alone.
A Permanent Install
Unlike a portable heater, the InstaShower mounts into the RV wall and vents outside. Plan for a proper installation rather than a quick hookup.
Product Specs
| Measurements | 15 inches by 15 inches by 14.4 inches |
|---|---|
| Flow rate | 3.6 gallons per minute |
| Temperature range | 95 to 123 degrees Fahrenheit |
| Weight | 30.9 pounds |
| Warranty | 2 years |
Stiebel Eltron 12 Plus Tempra Tankless Water Heater
Best Tankless Water Heater for Larger RVs
If you have a large fifth wheel or Class A motorhome, you need a heavy hitter. The Stiebel Eltron Tempra 12 Plus is a sleek, high-output electric unit capable of keeping up with high demand.
This is a whole-house unit, so it has the muscle to run a shower and a sink at once. At 12 kW on 240 volts, it draws close to 50 amps, which is why Stiebel Eltron asks for at least a 100-amp main service to run it.
Depending on your groundwater temperature, it pushes 1.3 to 2.5 GPM. Its 0.99 energy factor means almost no energy is wasted. The “Plus” in the name is its advanced flow control, which slows the water automatically to hold temperature when demand spikes.
Stiebel Eltron is a German maker with decades behind it, and the unit runs whisper-quiet, a real benefit in the tight quarters of an RV.
What We Like
Advanced Flow Control
This is the standout feature. If you demand more hot water than the unit can heat, lesser heaters simply give you lukewarm water. The Tempra Plus automatically slightly reduces the flow of water to ensure the temperature stays hot. No more cold shocks.
Incredible Efficiency
With a 0.99 energy factor, it is as efficient as it gets. The auto-modulation technology scales power usage instantly, ensuring you don’t trip breakers unnecessarily.
Silent Operation
Old tank heaters can rumble and hiss. This electronic unit is completely silent. You won’t even know it is running until the steam hits your mirror.
Informative Digital Display
The front display gives you real-time info on temperature and potential savings. It also features preset memory buttons, so you can save your preferred shower temperature.
What We Don't Like
Professional Installation Recommended
This is a high-voltage, high-amperage appliance. The plumbing is standard, but the wiring is complex and needs a heavy-duty circuit. Unless you are an electrician, hire a pro to wire it into your rig and avoid a fire hazard.
Easy to Undersize in the Cold
The 12 kW model is the smallest Tempra Plus, sized for one fixture or a warm-climate single shower. Owners who run it where the inlet water is genuinely cold tend to find the flow rate drops below what they expected, so match the unit to your coldest camping inlet temperature, not the spec-sheet best case.
Product Specs
| Measurements | 14.5 inches by 16.2 inches by 4.5 inches |
|---|---|
| Flow rate | 1.3 gallon to 2.5 gallons per minute |
| Temperature range | 86 to 140 degrees Fahrenheit |
| Weight | 13.5 pounds |
| Warranty | Seven-year warranty |
Eemax EEM24018 Electric Tankless Water Heater
Best Aesthetically Pleasing Tankless Water Heater Unit
The Eemax EEM24018 stands out with its distinctive metallic blue casing. But it isn’t just about looks; this is a sturdy 240-volt heater designed to provide consistent hot water.
It uses direct heating elements to warm water quickly. Like the others, it employs self-modulating technology to keep energy bills in check.
Eemax markets this as capable of running a sink and shower simultaneously. In a residential setting with warm groundwater, that is true. In an RV setting, it serves as a reliable main source of hot water, provided you have the 240V electrical capacity to run it.
What We Like
Serviceable Design
The metallic blue casing is tough and shields the internals well, and the digital interface keeps settings simple. It is compact enough (17 by 14 inches) to fit most RV utility closets. The threaded copper heating elements are also field-replaceable, so a worn element is a swap rather than a new heater.
Self-Modulating Power
The unit reads inlet flow and temperature and adjusts the power draw on the fly. This smooths out the “sandwich effect,” the bursts of cold water common in older tankless models.
Fast Heating
At 18 kW it heats water faster than the smaller 120V units, delivering a shower closest to a sticks-and-bricks home. Just plan the electrical work: it needs two 40-amp double-pole breakers, so it only fits rigs with real 240V capacity and panel space to spare.
What We Don't Like
High Electrical Requirements
This is a 240-volt unit, and many RVs only run on 120 volts. Confirm your rig is wired for 240V appliances before you buy, or it simply will not run.
Cold Inlet Caps Simultaneous Use
It is powerful, but cold inlet water eats into its margin. When the groundwater is very cold, you may have to pick a hot shower or running the dishes, not both at the same time.
Product Specs
| Measurements | 17 inches by 14 inches by 3.75 inches |
|---|---|
| Flow rate | 2.3 gallons per minute |
| Temperature range | 80 to 140 degrees Fahrenheit |
| Weight | 14.47 pounds |
| Warranty | Five-year warranty on leaks, one year on parts |
Camplux 2.64 GPM Tankless Propane Water Heater
Best Tankless Water Heater for Off-Grid Camping
Boondocking is about freedom, and the Camplux 2.64 GPM heater is built for it. This is a portable propane unit, not a permanent install, so you can set up an outdoor shower wherever you park.
You hang it up, connect a standard propane tank and a water hose, and you have hot water in seconds. That makes it a good fit for small trailers, teardrops, or van builds with no internal shower. The integrated handle makes it easy to move, and because the ignition runs on D-cell batteries, you do not need an electrical hookup at all.
What We Like
Truly Portable
You can move this unit wherever you need it. Use it to wash the dog, rinse off muddy hiking boots, or take a shower behind a privacy tent. It weighs about 18 pounds, so it is easy to stow away when travel days arrive.
Battery Powered Ignition
No generator? No problem. The ignition runs on two D-cell batteries, which makes it a dependable choice for deep wilderness camping where electricity is scarce.
Fires on Low Water Pressure
The burner kicks in at about 3.6 PSI and runs across a 3.6 to 110 PSI range, so it can light off a modest 12V pump or even some gravity-fed setups instead of demanding full city pressure. That low-pressure startup is what makes it practical for off-grid use where you are pumping from a jug or a stream.
Complete Kit Included
Camplux includes almost everything you need to get started right out of the box:
- Showerhead with on/off switch.
- 5-foot shower hose.
- CSA-approved gas hose and regulator.
- Garden hose adapters (quick connects).
- Mounting hardware.
What We Don't Like
Outdoor Use Only
This unit is not vented. It consumes oxygen and produces carbon monoxide. You must strictly use this outdoors or in an open-air environment. Do not install this inside your sleeping quarters.
Included Hose is Basic
The included shower hose is plastic and can kink. We recommend upgrading to a longer, flexible stainless steel hose for a better experience.
Product Specs
| Measurements | 12.8 inches by 6.1 inches by 21.65 inches |
|---|---|
| Flow rate | 2.64 gallons per minute |
| Temperature range | Not specified |
| Weight | 18 pounds |
| Warranty | N/A |
| Product | Award | Measurements | Weight (lbs) | Temp. Range (F) | Flow rate (GPM) | Warranty |
|---|---|---|---|---|---|---|
| EcoSmart 8 KW | Best For Eco-Friendly Camping | 11.5″ x 8″ x 3.75″ | 5.3 | 80 – 140 | 1.5 | Limited lifetime |
| Fogatti InstaShower 9 Pro | Best For High-Tech RVers | 15″ x 15″ x 14.4″ | 30.9 | 95 – 123 | 3.6 | 2 years |
| Stiebel Eltron 12 | Best For Larger RVs | 14.5″ x 16.2″ x 4.5″ | 13.5 | 86 – 140 | 1.3 – 2.5 | 7 years |
| Eemax EEM24018 | Best Aesthetically Pleasing | 17″ x 14″ x 3.75″ | 11.25 | 80 – 140 | 2.3 | 5-year on leaks, 1 year on parts |
| Camplux 2.64 GPM | Best For Off-Grid Camping | 12.8″ x 6.1″ x 21.65″ | 18 | N/A | 2.64 | N/A |
