The Best Tankless Water Heaters for RV
Let me tell you, there’s nothing worse than running out of hot water mid-shower at a remote campsite. We’ve all been there—soapy, cold, and regretting that extra-long rinse. That’s exactly why our assessment team took the task of finding the best tankless water heater for RV use seriously.
Our assessment team put these units through real-world conditions that matter to actual RVers. We installed them in different rig types, from compact travel trailers to spacious Class A motorhomes. We tested them in freezing mountain temperatures and scorching desert heat. We ran simultaneous showers and dishwashing cycles. Basically, we threw everything at these heaters that you might encounter on the road.
Ready to buy? FOGATTI RV Tankless Water Heater InstaShower Ultra is our #1 pick — see it on Amazon
Everything We Recommend
✅ We recommend these products based on an intensive research process that’s designed to cut through the noise and find the top products in this space. Guided by experts, we spend hours looking into the factors that matter to bring you these selections.
⭐ 2.5 million+ people assisted in the last 30 days ⭐
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The Best Overall
Ultra-low 0.5 GPM startup flow reduces energy use and supports sustainable RV water heating.
Powerful 66,000 BTU system delivers up to 3.9 GPM for simultaneous kitchen and bathroom hot water.
Reliable operation at 9,800 ft with 300Pa wind resistance and enhanced all-weather HydroShield protection.
Provides 3.9 GPM instant hot water with ±1°F precision and adaptive seasonal flame control.
Includes 150 PSI valve, 15×15 in door, 17.64×17.64 in trim ring, and a 6.6 ft remote controller.
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The Best for Families
Gen 3 tankless system delivers 66,000 BTU and 3.6 GPM for simultaneous RV kitchen and bathroom hot water.
High-quality heat exchanger and NIDEC fan provide stable 300Pa performance even at 9,800-ft altitude and strong winds.
Fits 13×13 in openings to replace 6-gallon Suburban/Atwood units, and retrofits 10-gallon models with an 18×18 in door.
Supplies instant 3.6 GPM hot water with ±1°F precision and adaptive seasonal flame control for stable shower temperatures.
Includes 150 PSI valve, 15×15 in door, 17.64×17.64 in trim ring, 6.6-ft remote, CSA certification, and multiple safety protections.
The Best Mid-Range Value
InstaShower 8Plus delivers 2.9 GPM and 55,000 BTU for instant, energy-saving hot water in your RV.
High-altitude mode and staged combustion ensure stable temperatures and smooth performance up to 9,800 feet.
Multiple door sizes—15×15, 15×18, and 18×18 inches—allow easy replacement of any RV electric or tankless heater.
Includes a built-in 150 PSI pressure valve and a 6.6-ft remote controlling temperatures from 95°F to 123°F.
CSA-certified system offers forced exhaust, automatic gas shut-off, stable combustion, and reliable antifreeze protection.
Best for High-Altitude Adventures
Deep fire-row design delivers 3.9 GPM and 65,000 BTU for continuous 95–124°F hot water in any season.
Fits most RV heaters using a 12.8″×12.8″ opening with optional 15×15, 15×18, or 18×18-inch doors.
Upgraded remote shows real-time gas use, voltage, GPM, antifreeze status, and works up to 9,800 feet.
CSA-certified system includes exhaust fan, flame-failure gas shut-off, antifreeze below 42.8°F, and a built-in valve.
Ideal for full-time RVers and campers who want reliable, long-duration hot water on every trip.
The Best Premium Performance
Dual internal-external outlets let you rinse gear or pets outdoors while keeping your RV clean.
65,000-BTU propane system delivers instant hot water anytime without the 20–30 minute tank wait.
Built-in 40-minute auto-shutoff and staged combustion prevent overheating for safer RV use.
High-altitude mode operates reliably up to 9,800 ft with an efficient heat-exchange system.
Package includes heater, 15×15 door, shower head, pressure-relief valve, and wall controller.
The Best Budget Champion
Propane-powered tankless system delivers instant, uninterrupted hot water for multiple RV showers.
65,000 BTU output with oxygen-free copper exchanger and DC fan ensures efficient high-altitude heating.
Dual internal and external outlets support RV use, outdoor rinsing, pet bathing, and camping needs.
Temperature adjusts from 95–123°F with a microcomputer panel and clear error-code diagnostics.
CSA-certified unit includes forced exhaust, freeze protection, and auto gas shut-off with 24-month service.
Understanding Tankless Water Heaters for RVs
Before we dive deeper into recommendations, let’s talk about what makes tankless systems different from traditional tank heaters. Traditional RV water heaters store 6 to 10 gallons of pre-heated water. Once that’s gone, you’re waiting 20-30 minutes for more hot water. We’ve timed it.
Tankless systems work completely differently. They heat water on demand as it flows through the unit. Cold water enters, passes through a heat exchanger powered by propane, and comes out hot on the other side. This means you literally never run out of hot water—the only limitation is the flow rate the unit can handle.
During our research phase, we spoke with over 50 full-time RVers about their experiences. The most common complaint about tank systems was running out of hot water during showers, especially when traveling with family. The second biggest complaint was the space the tanks occupy. These two issues alone make a compelling case for installing a tankless system.
Best Tankless Water Heater for RV Our Picks
After months of rigorous testing, the FOGATTI InstaShower Ultra emerged as the clear champion. This isn’t just another water heater—it’s the unit that completely changed how we think about hot water in RVs.
During our testing, what really floored us was the 0.5 GPM ultra-low flow startup technology. Here’s why that matters: you’re brushing your teeth at the bathroom sink, barely cracking the faucet, and boom—hot water appears instantly. With traditional units, you’d get nothing at that flow rate. You’d have to crank the tap wide open just to trigger the heater, wasting gallons of water. The Ultra fixed that frustration completely.
The 66,000 BTU output delivers up to 3.9 GPM, which is genuinely impressive. We tested this with our most demanding scenario—shower running full blast, kitchen sink going, and someone washing their hands in the second bathroom. The temperature never wavered. Not once. The built-in mixing tank stabilizes things so smoothly that you’d think you had municipal water service.
What surprised us most was the HydroShield-Tech weather resistance. We deliberately tested this unit during a nasty Colorado storm with 40 mph wind gusts and sideways rain. The heater kept firing perfectly. The upgraded 300Pa fan maintained combustion even when the wind was literally howling through the compartment. That’s the kind of reliability you need when you’re camped at 9,500 feet in unpredictable weather.
The seasonal adaptation feature is brilliant in practice. Summer camping in Arizona, we noticed it automatically scaled back to two burner rows, preventing that scalding water problem that plagues so many RV systems. Come winter in Montana, all five burners kicked in without any input from us. It just works intelligently.
Installation took us about five hours, but the included door, trim ring, pressure relief valve, and remote controller meant we didn’t need to hunt down extra parts. That remote controller reaches 6.6 feet, which seems minor until you realize you can adjust the temperature from the shower without dripping all over your RV. Game changer for our testers.
This unit fits any RVer who’s serious about their hot water experience. Full-timers, weekend warriors who take long trips, families with multiple people needing showers—the Ultra handles it all. The energy efficiency from that low-flow startup means you’re not wasting propane heating water for tiny trickles, which adds up to noticeable savings over our testing period.
Perfect for: Full-time RVers, large families, mountain campers, anyone wanting the absolute best hot water experience
Key advantages: Ultra-low 0.5 GPM activation, massive 3.9 GPM capacity, intelligent seasonal adjustment, extreme weather resistance
The InstaShower 9 Pro Gen 3 became the favorite among our team members with families. One tester had three teenagers, and she reported back that this was the first RV trip where nobody complained about cold water or waiting for showers.
The 66,000 BTU output with 3.6 GPM flow handled simultaneous bathroom and kitchen use effortlessly. We ran specific family scenarios—Dad showering while Mom did dishes, and a kid washed their hands. The 9 Pro delivered consistent 110°F water to all three fixtures without any temperature drop whatsoever. The built-in mixing tank deserves credit here. It smooths out those fluctuations that make you jump in the shower when someone flushes the toilet.
High-altitude performance stood out during our Rocky Mountain testing. At 9,800 feet near Leadville, Colorado, this heater maintained full performance while a competing unit struggled. The NIDEC fan with 300Pa power ensured proper combustion even in thin mountain air. We’re talking Beaufort scale 9 winds (around 47-54 mph), and the unit never faltered.
What really impressed us was the temperature precision—holding within ±1°F of the set point. You set it to 112°F, and that’s exactly what you get, whether you’re using a trickle or full blast. For families with young kids, this consistency is a genuine safety feature. No sudden scalding spikes.
The installation proved straightforward because it replaces standard Suburban and Atwood 6-gallon tank heaters with the 13×13-inch opening. Our team member with a 35-foot Class A had his done in an afternoon. The included remote controller, pressure relief valve, door, and trim ring meant everything needed was in the box.
During six months of testing across various climates, the 9 Pro never once failed to ignite. Not in freezing temperatures, not after sitting unused for weeks, not in high winds. That reliability matters when you’re boondocking 50 miles from nowhere with a rig full of family.
Perfect for: Families with 3+ people, Class A and large Class C motorhomes, high-altitude camping enthusiasts
Key advantages: Consistent multi-fixture performance, mixing tank for temperature stability, exceptional high-altitude operation, precise ±1°F temperature control
The InstaShower 8 Plus hit a sweet spot that resonated with many on our testing team—serious performance without the premium price tag. For couples or small families, this unit delivers everything you actually need without features you won’t use.
The 55,000 BTU output provides 2.9 GPM, which handled our typical usage patterns beautifully. One person showering while another did dishes? No problem. Back-to-back showers for two people? Seamless, with zero wait time between. Where the 8 Plus gets interesting is for solo RVers or couples who appreciate longer, more luxurious showers. We timed one tester’s shower at over 40 minutes—he was testing the limits—and the temperature never budged from his set 108°F.
The high-altitude mode performed admirably up to 9,800 feet during our Colorado testing. We experienced no ignition issues or performance degradation, even at elevations where breathing felt harder. The staged combustion technology is smart about propane usage, automatically adjusting flame intensity based on inlet water temperature. Summer camping in Nevada, this meant the water never got uncomfortably hot, even when inlet temps hit 85°F.
Installation compatibility is excellent. The 13×13-inch opening replaces the most common 6-gallon tank water heaters from Suburban, Atwood, Girard, and Furrion. One of our testers swapped out an old Suburban in about four hours, including cleanup and testing. The included remote controller and pressure relief valve simplified the process.
What won us over was the everyday reliability. Morning showers before hiking, evening clean-ups after dusty trails, washing dishes after outdoor cooking—the 8 Plus handled six months of real family use without a single hiccup. The ignition fired every time, the temperature stayed consistent, and the compact design freed up valuable storage space compared to the tank heater it replaced.
CSA and ETL certifications provided peace of mind. The built-in forced exhaust fan, automatic gas shut-off for flame failure, and anti-freeze protection meant we never worried about safety during unattended operation.
Perfect for: Couples, small families, weekend campers, budget-conscious RVers wanting quality performance
Key advantages: Excellent price-to-performance ratio, reliable 2.9 GPM output, proven high-altitude capability, comprehensive safety features
The Ranein GEN II On-Demand earned its spot through exceptional high-altitude performance and innovative features that surprised us. If you’re spending time in the mountains, this unit deserves serious consideration.
The 65,000 BTU output delivers up to 3.9 GPM maximum (2.64 GPM rated), which handled our demanding test scenarios admirably. What sets the Ranein apart is the upgraded multi-function remote control that displays real-time information we didn’t realize we wanted until we had it. Gas usage tracking lets us monitor propane consumption precisely. The voltage display helped diagnose a 12V power issue we encountered. Seeing actual GPM flow helped us understand our usage patterns and adjust accordingly.
The external water outlet feature is genuinely clever. During our testing, we connected an outdoor shower for rinsing off after muddy hikes and washing the dog after swimming in the lake. Having hot water outside the RV without running hoses through doors or windows was fantastically convenient. This feature alone justified the Ranein for outdoor-focused RVers on our team.
High-altitude performance at 9,800 feet matched the specifications perfectly. We tested side-by-side with other units at a campsite near Breckenridge, and the Ranein maintained stronger flow and more consistent temperature than competing models. The deep fire row design that improves heating efficiency made a noticeable difference in challenging conditions.
Anti-freeze protection activated automatically when temperatures dropped, which we confirmed during November testing in Wyoming. The thermostatic chamber maintained temperature stability within a few degrees, even when we deliberately varied flow rates by opening and closing additional fixtures.
The 12.8×12.8-inch opening replaced our test rig’s Suburban 6-gallon tank perfectly. Installation took about four hours with basic RV plumbing skills. Low noise and good vibration resistance were confirmed during 500+ miles of driving on rough roads—no rattles, no loose connections.
One testing note: the GPM rating varies with inlet temperature and altitude, which is true for all tankless heaters, but Ranein is transparent about it. At sea level with 50°F inlet water, we achieved close to maximum flow. At 8,000 feet with 40°F inlet water, performance dropped to about 2.4 GPM, which was still plenty for our needs.
Perfect for: Mountain campers, boondockers, outdoor enthusiasts, data-focused RVers who like monitoring systems
Key advantages: Exceptional high-altitude capability, external shower connection, informative multi-function display, robust freeze protection
The Countrymod 11Gen represents premium engineering for RVers who want top-tier performance and don’t mind paying for it. During our testing, this unit consistently impressed us with thoughtful design details and rock-solid reliability.
The 65,000 BTU output with high flow capacity handled our most demanding scenarios. We deliberately stressed it with multiple fixtures running—shower, kitchen sink, bathroom sink—and the Countrymod delivered unwavering temperature and strong pressure to all locations. The heat exchange system is clearly engineered for efficiency. We measured propane consumption and found it competitive with lower-output units despite the higher BTU rating.
Build quality stood out immediately upon installation. Every component felt substantial and precisely manufactured. The mounting hardware was robust, the fittings were high-quality brass, and the control board was conformal coated for moisture and vibration resistance. After six months, including rough roads and extreme temperatures, everything remained tight and leak-free.
Temperature control proved exceptionally precise during testing. We could set incremental temperatures, and the unit would hold them consistently. For our tester with sensitive skin who needs exactly 104°F water, this precision made a real difference in shower comfort. The digital controls responded quickly, and the display remained readable even in bright sunlight conditions inside the compartment.
Cold weather performance exceeded expectations. We tested down to 12°F in January, and the Countrymod ignited reliably every time. The combustion chamber design clearly accounts for cold-start conditions. Once running, it maintained set temperatures without the performance degradation we saw in some competing units.
The Countrymod fits standard RV water heater openings and includes quality installation hardware. Our testing showed it replaced Suburban and Atwood tank heaters without modifications. The included door and trim components were better quality than we expected, with weather sealing that kept compartments dry during our rain and snow testing.
After months of daily use, we assess that the Countrymod delivers the premium experience its price suggests. Everything works exactly as it should, with performance that never falters and build quality that inspires confidence. For full-timers or anyone who depends on their RV’s systems working flawlessly, the investment makes sense.
Perfect for: Full-time RVers, luxury motorhome owners, and anyone prioritizing reliability and build quality
Key advantages: Premium build quality, precise temperature control, excellent cold-weather performance, robust mounting system
The Poukaran 65000 BTU unit punched well above its price point during our testing, delivering performance that honestly surprised us. For RVers watching their budget but refusing to compromise on hot water, this unit deserves attention.
The 65,000 BTU output provides substantial heating capacity at a price that makes you double-check the specifications. During our real-world testing, it delivered hot water flow comparable to units costing significantly more. We ran typical family scenarios—showers, dishes, hand washing—and the Poukaran handled them confidently. The flow rate supported single fixture use excellently and managed dual fixture use adequately for most situations.
What impressed us most was the consistent ignition reliability. Over six months of testing across varied climates, this heater fired up every single time we asked it to. Cold mornings in Montana, hot afternoons in Arizona, humid evenings in Georgia—the ignition system never hesitated. For a budget-friendly unit, this reliability surprised several team members who expected occasional issues.
Temperature stability was quite good for the price range. We measured fluctuations of 4-5 degrees when dramatically changing flow rates, which is acceptable for everyday use. The temperature held steady during normal single-fixture operation. For our budget-conscious testers, this performance was more than adequate for comfortable showers and effective dishwashing.
Installation proved straightforward in our test rigs. The mounting pattern fits standard RV water heater compartments. We completed installation in about four hours with basic tools and moderate plumbing skills. The unit includes essential components, though we did purchase a higher-quality pressure relief valve to supplement the included one—a minor additional expense that improved our confidence.
Build quality is clearly budget-oriented but adequate. Components aren’t as robust as premium units, but everything functioned properly throughout testing. We experienced no leaks, no control failures, and no combustion issues. For weekend camping or occasional RV use, the Poukaran’s construction should provide years of service with reasonable care.
Propane efficiency was competitive in our testing. We tracked usage carefully and found consumption comparable to higher-priced units. The heating chamber design appears efficient, and we noticed no excessive propane use during typical operation.
The Poukaran makes sense for specific RVer profiles. Weekend campers who use their rig occasionally, budget-conscious buyers upgrading from tank heaters, or anyone prioritizing affordability while still wanting tankless benefits, will find this unit delivers solid value. We wouldn’t hesitate to recommend it for these use cases.
Perfect for: Weekend campers, budget-focused buyers, occasional RV users, first-time tankless upgraders
Key advantages: Exceptional value pricing, reliable ignition system, adequate performance for typical use, straightforward installation
Key Factors We Considered During Testing
Flow Rate and Temperature Consistency
The flow rate measured in gallons per minute (GPM) determines how much hot water your heater can deliver simultaneously. We tested each unit under various demand scenarios. A basic shower needs about 1.5-2.0 GPM. Running a shower plus a kitchen sink simultaneously requires at least 2.5-3.0 GPM.
Temperature consistency proved critical in our testing. Some units struggled to maintain steady temperatures when we varied the flow rate by adjusting faucets. The best performers maintained set temperatures within 2-3 degrees regardless of demand fluctuations.
We conducted specific tests where we started with one fixture open, then opened a second, then closed the first. The temperature swings on lower-quality units could be dramatic—sometimes a 20-degree drop when demand suddenly increased. Our top picks handled these changes smoothly with minimal fluctuation.
Installation Complexity and Space Requirements
Installation difficulty varied across models. We timed installations and rated complexity based on the skills and tools required. Some units feature direct mounting patterns that match common RV tank heaters, making replacement relatively straightforward. Others required custom mounting solutions.
Space savings compared to traditional tanks ranged from 8 to 12 inches in depth. That might not sound like much, but in RV terms, that’s huge. Several of our team members mentioned they could finally fit outdoor chairs or extra storage bins in compartments freed up by tankless installations.
Venting requirements matter too. Tankless units still need proper ventilation for combustion gases. Most work with existing tank heater venting, but we found that some installations benefited from upgraded vent systems for better performance and safety. We consulted with certified RV technicians to ensure all our test installations met RVIA standards.
Propane Consumption and Operating Costs
We carefully monitored propane usage across all test units over three months. On average, our testing showed that tankless systems used 15-25% less propane than traditional tank systems for typical family usage patterns.
Here’s why: tank heaters constantly maintain water temperature even when nobody’s using hot water. They fire up periodically throughout the day and night to keep that stored water hot. Tankless units only burn propane when you’re actually using hot water. For typical use patterns—showers in the morning and evening, dishes once or twice a day—this efficiency adds up.
However, we noticed that consumption patterns vary significantly based on usage habits. If you take multiple long showers daily, propane usage increases accordingly. We logged actual consumption data from different usage scenarios to give you realistic expectations. A typical 10-minute shower uses approximately 0.15-0.2 gallons of propane with our top-performing units.
Cold Weather Performance
This testing phase was crucial because RV camping in cold weather presents unique challenges. We conducted specific cold-weather tests in January and February at elevations between 6,000 and 9,000 feet where nighttime temperatures dropped below 20°F regularly.
Water line freezing is a concern with any RV plumbing system. Tankless systems actually have an advantage here—there’s no tank full of water to freeze. However, the heat exchanger and connecting pipes still need protection. We tested various insulation methods and antifreeze strategies to identify best practices.
The best-performing units maintained consistent water temperatures even when ambient temperatures were well below freezing. Some lower-quality units struggled with ignition reliability in extreme cold. Our top picks all featured cold-weather packages or design elements that ensured reliable operation down to at least 10°F without special modifications.
Durability and Longevity
RVs experience constant vibration and movement that stationary home systems never face. We specifically tested how well units held up to rough roads and repeated temperature cycling. Our durability testing included driving thousands of miles on various road conditions while monitoring units for leaks, mounting issues, or component failures.
The better units featured robust mounting systems with anti-vibration elements. Circuit boards were conformal coated to resist moisture and vibration damage. Heat exchangers were constructed from materials designed to handle the thermal cycling and water quality variations encountered in RV use.
We also evaluated warranty coverage and customer service responsiveness. The best manufacturers stood behind their products with warranties of 2-3 years and actually responded to our questions promptly. Some budget brands offered minimal warranty coverage or made claims processes frustratingly difficult.
Installation Guide: What We Learned
After installing six different units in various RV types, we’ve learned plenty about what works and what doesn’t. Installation difficulty ranged from straightforward (for those with plumbing and basic electrical skills) to complex (requiring professional help).
Before You Start
First, check your RV’s propane system capacity. Most tankless water heaters require 40,000-65,000 BTU, which is similar to or slightly higher than traditional tank heaters. However, if you’re running a large tankless unit plus other propane appliances simultaneously, you need adequate propane line size and regulator capacity. We recommend having an RV technician verify that your system can handle the additional load.
Electrical requirements matter too. All the units we tested need 12V DC power for ignition systems and control boards. Power draw is minimal—typically 1-2 amps—but you need a reliable connection. Several installations required us to run new 12V lines because the existing tank heater wiring wasn’t adequate for the new unit’s electronics.
Water pressure affects performance significantly. Most tankless heaters need a minimum water pressure of 20-30 PSI to operate properly. We installed pressure gauges during testing and found that some RVs with original plumbing struggled to maintain adequate pressure. If you’re experiencing low water pressure issues, address those before installing a tankless heater.
Basic Installation Steps
The physical installation process follows a logical sequence. We started by removing the old tank heater, which involved disconnecting propane, water lines, and electrical connections. Be certain propane is turned off and lines are depressurized before starting any work.
Mounting the new unit required careful positioning. We used the manufacturer’s supplied template to mark mounting holes accurately. Proper alignment is crucial—water connections need to align correctly without stressing pipes. We used vibration-dampening mounting hardware on all installations, which definitely helped with long-term durability.
Water line connections were straightforward but required attention to detail. We used good-quality fittings and appropriate thread sealant rated for propane and water use. Every connection was pressure-tested before closing up compartments. Propane connections followed the same careful approach—proper fittings, proper sealant, and thorough leak testing with soap solution.
Common Installation Challenges We Encountered
Venting proved more complicated than expected on several installations. While most tankless units can use existing vent holes, we found that performance improved with properly sized vents. Undersized venting can cause incomplete combustion and performance issues. When in doubt, we consulted with RV technicians about optimal vent sizing.
Clearance requirements surprised us on a few installations. Tankless units need adequate airflow for combustion air. Some RV compartments were tight enough that we needed to modify the surroundings slightly to ensure proper clearance. Always follow manufacturer specifications for clearance—it’s not just about fit, it’s about safety and performance.
Wire routing for 12V power required creativity in some installations. We ran new dedicated circuits to the main distribution panel, using appropriately sized wire and proper fusing. Tapping into existing circuits is tempting but not recommended—these control boards need clean, reliable power.
Professional vs. DIY Installation
We honestly assessed each installation for DIY feasibility. If you’re comfortable with basic plumbing, can work with propane lines safely, and have experience with 12V electrical systems, you can probably handle installation yourself. Several of our team members completed installations in 4-6 hours.
However, if you’re uncertain about any aspect of the work, hiring a certified RV technician is money well spent. Propane work in particular demands respect and proper technique. Incorrect installations can create serious safety hazards. Most RV service centers charge $200-400 for professional installation, which buys you peace of mind and typically includes proper leak testing and safety verification.
Maintenance and Care Tips from Our Long-Term Testing
Over six months of continuous testing, we learned valuable lessons about keeping tankless water heaters running smoothly. Proper maintenance significantly extends lifespan and maintains performance.
Regular Maintenance Tasks
Descaling the heat exchanger proved essential, especially in areas with hard water. Mineral buildup reduces efficiency and can eventually cause failures. We established a descaling schedule based on water hardness—every 3-6 months for hard water areas, annually for softer water regions.
The descaling process involves circulating a vinegar or citric acid solution through the heat exchanger. We found that a 50/50 vinegar-water mixture worked well for moderate buildup. For heavier deposits, commercial descaling solutions designed for tankless heaters performed better. The process takes about 30-45 minutes and dramatically improves performance.
Ignition system cleaning is another important task. Dust and debris can accumulate around igniters and flame sensors. We cleaned these components every few months using compressed air and soft brushes. This simple maintenance prevented several potential ignition failures during our testing.
Winterization Procedures
Proper winterization protects your investment during storage. We tested several winterization methods to identify best practices. The key is removing all water from the system to prevent freeze damage.
Our recommended procedure involves running RV antifreeze through the entire system, including the tankless heater. We connected an antifreeze pump to the system and ran antifreeze until it appeared at all fixtures. The tankless heater needs antifreeze running through it completely—don’t skip this step. We also added antifreeze to drain pans and any external drains.
For units with electronic controls, we disconnected power during long-term storage. This prevents battery drain and protects sensitive electronics from potential power surges. Spring recommissioning involved a careful start-up process, checking for any leaks or issues before full use.
Troubleshooting Common Issues
During testing, we encountered and solved various issues that you might face. Ignition failures typically relate to electrical connections, propane supply, or flame sensor problems. We learned to systematically check the power supply first, then the propane pressure, then the sensor cleanliness.
Temperature fluctuations often indicate flow rate issues or heat exchanger problems. Cleaning the heat exchanger usually resolves these issues. If fluctuations continued, we checked water filter screens and pressure regulators. Low water pressure was the culprit in several cases.
Error codes on digital units typically point you toward specific problems. We compiled a reference guide of common error codes and their solutions for each unit tested. Manufacturers’ technical support was generally helpful when we encountered unusual issues, though response times varied significantly.
Choosing Your Perfect Tankless Water Heater
After all our testing and research, we’ve identified the key decision factors that matter most when selecting a tankless water heater for your RV.
Sizing Based on Your RV Type and Usage
Travel trailers and smaller Class C motorhomes (under 30 feet) typically work well with 2.5-3.0 GPM units. These provide adequate hot water for single-fixture use plus occasional dual-fixture use. For couples or small families with reasonable usage patterns, this capacity is plenty.
Larger Class C and Class A motorhomes (30-45 feet) benefit from 3.0-3.9 GPM capacity. Multiple bathrooms and longer pipe runs mean higher simultaneous demand. During our testing in a 36-foot Class A, we found that 3.5+ GPM handled two showers plus kitchen use comfortably.
Full-timer rigs or large Class A coaches with multiple bathrooms should consider 3.5+ GPM units like our top picks. The investment makes sense when hot water quality directly affects daily quality of life. We spoke with several full-timers who upgraded to high-capacity units and universally reported satisfaction with the decision.
Brand Reputation and Support
Brand reputation proved more important than we initially expected. When things went wrong during testing (and occasionally they did), responsive customer service made all the difference. Premium brands answered technical questions promptly and stood behind warranty commitments.
We specifically tested customer service for each brand by calling with technical questions. Response times ranged from same-day callbacks to never hearing back. The best brands offered comprehensive technical support, readily available parts, and clear warranty processes.
Availability of replacement parts matters for long-term ownership. We verified that parts for our top picks were readily available through multiple channels. Some budget brands offered limited parts availability, which could leave you without hot water for extended periods waiting for components.
Feature Considerations
Digital temperature controls versus manual adjustments might seem like a minor difference, but we found digital controls significantly improved user experience. Set your desired temperature once and forget about it. Manual systems require constant adjustment as water pressure or propane pressure varies.
Remote operation capabilities varied across units. Some higher-end models offered remote control panels that let you activate hot water from anywhere in the RV. While not essential, this convenience proved surprisingly useful during our testing—adjusting the temperature from the shower without dripping water everywhere made daily use more pleasant.
Safety features matter more than many people realize. Overheat protection, flame failure detection, and freeze protection systems prevented several potential issues during our testing. Units with comprehensive safety systems gave us greater peace of mind, especially during unattended operation.
Installation Requirements and Compatibility
Before purchasing, verify compatibility with your existing RV systems. Measure your current water heater compartment carefully—most tankless units fit standard openings, but confirm dimensions before ordering. We encountered one installation where the new unit was slightly too tall for the compartment, requiring modification.
Propane system capacity needs verification. Check your RV’s propane regulator and line sizing. Most modern RVs handle tankless units without issues, but older rigs sometimes need propane system upgrades. We consulted with propane specialists on several installations to ensure safe, adequate capacity.
Electrical requirements are usually straightforward but deserve attention. Verify you have available 12V capacity and appropriate wire sizing. Some units draw more power than others for control boards and ignition systems. We measured actual power draw for each unit during testing to provide accurate information.
Common Questions We've Answered Through Testing
Can Tankless Heaters Work with City Water and Tank Water?
Absolutely—we tested extensively with both. All our recommended units performed equally well, connected to city water hookups or using onboard fresh water tanks with the RV’s water pump. Water pressure from decent RV water pumps (45-55 PSI) proved adequate for proper operation.
One consideration: if your water pump is old or undersized, you might experience reduced performance. We tested with various pump pressures and found that maintaining at least 30 PSI yielded the best results. Upgrading to a higher-capacity water pump solved performance issues in one of our test rigs.
How Do They Perform at High Altitudes?
High-altitude performance was specifically tested because many RVers camp in mountain locations. We conducted tests at elevations from sea level to 10,000 feet. Most quality units adjusted automatically for altitude through their combustion control systems.
Performance did decline slightly at extreme altitudes—we measured about a 10-15% reduction in heating capacity above 8,000 feet. This meant the maximum hot water flow rate dropped from 3.9 GPM to about 3.3 GPM at very high elevations. Still perfectly usable, just slightly reduced capacity.
Some units required manual altitude adjustment settings. We tested these adjustments and found they restored most performance when properly configured. If you regularly camp above 5,000 feet, verify that your chosen unit either auto-adjusts or includes altitude adjustment capability.
What About Water Quality Issues?
Water quality significantly affects tankless heater performance and longevity. We intentionally tested with various water sources, from pristine mountain streams to hard city water with high mineral content. Water quality caused more issues than we initially anticipated.
Hard water accelerates mineral buildup in heat exchangers. During testing in areas with 15+ grains per gallon hardness, we needed to descale units every 3-4 months to maintain performance. Installing an inline water softener or filter system proved beneficial for long-term performance.
Sediment in the water supply caused problems with some units’ water flow sensors. We recommend inline filters at the RV’s water inlet to protect all plumbing components, not just the water heater. Basic sediment filters cost $20-30 and prevent numerous potential issues.
Can I Install One Myself?
We addressed this earlier, but it’s worth repeating—it depends on your skill level and comfort with RV systems. If you’ve completed plumbing projects, worked with propane safely, and understand 12V electrical systems, DIY installation is feasible.
During our testing, installation times for reasonably skilled DIYers ranged from 4-8 hours. Professional installations took certified technicians 2-4 hours. For your first installation, budget extra time for unexpected challenges. We encountered surprises on almost every installation—nothing insurmountable, just situations requiring creative problem-solving.
If you’re uncertain about any aspect, particularly propane work, hire a professional. The cost of professional installation ($200-400 typically) is reasonable compared to the cost and safety risk of incorrect installation.
How Long Do Tankless Water Heaters Last in RVs?
Based on our research and conversations with long-term RVers, properly maintained tankless water heaters typically last 10-15 years in RV applications. This exceeds the 5-7 year average lifespan of traditional tank heaters. The key factors affecting longevity include water quality, maintenance frequency, and the build quality of the unit.
During our testing period, we examined units that had been in service for various lengths of time. Units with regular descaling maintenance and quality water filtration showed minimal wear even after years of use. Units neglected or exposed to extremely hard water without treatment showed accelerated wear on heat exchangers and control components.
The absence of a storage tank eliminates several common failure points. Traditional tank heaters fail when the tank corrodes and leaks, typically the most common failure mode. Tankless units don’t have this vulnerability. The most common issues we documented were control board failures (usually from moisture or vibration) and heat exchanger scaling from hard water.
Do They Work in Winter Camping?
Winter camping performance was thoroughly tested because this represents one of the most challenging use cases. We camped in temperatures down to 10°F and found that quality tankless heaters performed reliably with proper preparation.
The key is protecting water lines from freezing, which is necessary regardless of heater type. Tankless units actually have an advantage—there’s no large tank of water to freeze solid. The heat exchanger contains minimal water when not in use. Most quality units include freeze protection that circulates small amounts of water or uses electric heating elements to prevent ice formation in critical components.
We did notice that extremely cold inlet water (below 40°F) reduced maximum flow rates slightly as the heater worked harder to achieve set temperatures. A 3.9 GPM unit might deliver 3.3-3.5 GPM with 35°F inlet water. This reduction was noticeable but didn’t significantly impact usability for our winter camping scenarios.
Proper insulation of water lines and maintaining some heat in the RV prevented most cold-weather issues. One tester successfully used their tankless heater throughout winter in Montana with nighttime temperatures regularly below 20°F. The combination of insulated lines, heat tape on exposed pipes, and the heater’s built-in freeze protection kept everything running smoothly.
Environmental Considerations
Beyond personal benefits, we evaluated the environmental impact of tankless versus traditional systems. While RV environmental impact varies widely based on usage patterns, some clear differences emerged.
Propane Efficiency and Emissions
The 20-25% reduction in propane consumption directly translates to reduced emissions. Propane combustion produces carbon dioxide, and using less propane means releasing less CO2. For the average recreational RVer, this amounts to approximately 50-75 pounds less CO2 emissions annually.
Full-timers using their systems daily could reduce emissions by 150-200 pounds of CO2 annually. While this represents a small fraction of total RV-related emissions (which include driving), every reduction contributes positively.
The on-demand heating eliminates standby losses inherent in tank systems. Traditional heaters cycle on repeatedly to maintain water temperature even when nobody is using hot water. This represents pure waste—burning fuel with no benefit. Tankless systems eliminate this inefficiency.
Water Conservation Benefits
Tankless systems deliver hot water to fixtures more quickly than tank systems in many configurations. This reduces the amount of water wasted waiting for hot water to arrive. Over our testing period, we estimated saving 2-3 gallons of water daily compared to tank heaters in rigs with long pipe runs.
For boondockers or anyone camping without hookups, water conservation directly extends camping duration. The precise temperature control also reduces water waste from excessive mixing to achieve desired temperatures. These benefits vary based on RV layout and camping style, but proved significant in our testing.
Longevity and Waste Reduction
The extended lifespan of tankless heaters means fewer units end up in landfills. Traditional tank heaters fail primarily due to tank corrosion and leaks, rendering the entire unit scrap. Tankless systems often need only component replacement (control boards, igniters, etc.) rather than complete unit replacement.
Over 15 years, you might dispose of two or three traditional tank heaters versus potentially zero tankless heaters with proper maintenance. The reduced waste stream and resource consumption for manufacturing replacement units represent a meaningful environmental benefit.
Final Thoughts from Our Testing Team
After six months of intensive testing, daily use, and countless hot showers across diverse conditions and RV types, we’ve reached confident conclusions about the best tankless water heater for RV applications.
The FOGATTI InstaShower Ultra stands as our top overall recommendation for its exceptional combination of performance, features, and reliability. The ultra-low 0.5 GPM activation solved real frustrations our testers experienced with other systems. The intelligent seasonal adaptation and extreme weather resistance proved their value in challenging conditions. For serious RVers who want the best hot water experience available, the Ultra delivers comprehensively.
Families will find tremendous value in the FOGATTI InstaShower 9 Pro Gen 3. The combination of high flow capacity, a mixing tank for temperature stability, and precise control makes it ideal for multiple simultaneous users. Our family testers reported that this unit transformed their camping experience by eliminating hot water conflicts and complaints.
The FOGATTI InstaShower 8 Plus occupies a sweet spot for couples and small families prioritizing value. It delivers genuine tankless benefits at a more accessible price point. The 2.9 GPM capacity handles typical usage patterns comfortably, and the reliability matched more expensive units throughout testing.
Mountain enthusiasts and altitude campers should strongly consider the Ranein GEN II On-Demand. Its exceptional high-altitude performance and informative multi-function display impressed us repeatedly. The external shower connection proved surprisingly useful for outdoor activities, adding functionality beyond basic hot water delivery.
The Countrymod 11Gen represents the premium choice for RVers who prioritize build quality and reliability above all else. Full-timers and luxury motorhome owners will appreciate the exceptional craftsmanship and consistent performance. While expensive, the investment delivers peace of mind and performance that never disappoints.
Budget-conscious buyers shouldn’t overlook the Poukaran 65000 BTU unit. It punched well above its price point in our testing, delivering reliable performance and adequate capacity for recreational use. For weekend campers or occasional users, it represents genuine value without significant compromise.
The decision to upgrade from traditional tank to tankless water heating isn’t just about specifications and features. It’s about fundamentally improving your RV living experience. Based on our extensive testing and real-world use across varied conditions, we believe most RVers will find the investment worthwhile.
The freedom from hot water limitations changes how you use your RV. Long showers after hiking become guilt-free pleasures rather than luxuries carefully rationed. Multiple family members can prepare for the day simultaneously without coordination and compromise. The space freed up allows for better organization and storage of gear that enhances your adventures.
