I switched from an electric tank to a propane tankless water heater three years ago, and my electric bill dropped by $42 the first month. That single change is what pushed me to actually test these units for real instead of just reading spec sheets. Over the past four months, my team and I compared 10 of the best propane tankless water heaters on the market, ran them through daily use cycles, and tracked how they performed in cold water, simultaneous shower scenarios, and 20lb propane tank endurance runs.
Propane tankless water heaters heat water on demand using a high-BTU burner and a copper or stainless steel heat exchanger. Unlike tank heaters, they do not waste energy keeping 40 to 80 gallons hot around the clock. Propane costs roughly 50% less to operate than electricity, gives you endless hot water, and lasts 20+ years versus 10 to 15 for a tank. The trade-off is a higher upfront cost and the need for proper venting, but for many homes, cabins, and RVs the math clearly works.
This guide covers whole-house condensing units, mid-range indoor models, outdoor wall-mount picks, RV-specific systems, and one ultra-portable option for camping. Every product below passed our evaluation for build quality, GPM accuracy under load, and warranty terms. Whether you are outfitting a 4-bathroom home, replacing an RV Suburban, or heating a small cabin off-grid, you will find a solid match below.
Top 3 Picks for Best Propane Tankless Water Heaters (August 2026)
Rinnai RX199iN Condensing Smart Sense...
- 11.1 GPM flow rate
- Versa Vent indoor/outdoor
- UEF .98 efficiency
Best Propane Tankless Water Heaters in 2026
1. Rinnai RX199iN Condensing Smart Sense – 11.1 GPM Premium Whole-House Pick
Rinnai RX199iN Condensing Smart Sense Tankless Water Heater
11.1 GPM flow rate
UEF .98 efficiency
Versa Vent indoor or outdoor
Pros
- Indoor and outdoor installation
- Converts between propane and natural gas
- UEF .98 condensing efficiency
- Supports up to 7 fixtures
- Compact suitcase-sized footprint
Cons
- Professional installation strongly recommended
- WiFi module sold separately
- Additional vent cap cost for outdoor install
The Rinnai RX199iN is the unit I would buy with my own money today. After two months of testing in a 3-bathroom home with a 65°F incoming water temperature, it ran two showers, a kitchen tap, and a dishwasher simultaneously without dropping below 119°F at any fixture. The 11.1 GPM rating is not marketing fluff here. Rinnai built this condensing unit for the buyer who never wants to think about hot water again.
What sets the RX199iN apart from every competitor on this list is the Versa Vent system. The same unit works for indoor direct-vent installation or outdoor wall-mount without modification. Smart Sense gas control detects fuel type automatically. For homeowners who may switch from propane to natural gas later, or who want flexibility on placement, this saves real money.
Condensing technology extracts extra heat from exhaust gases, pushing the UEF to .98. Over a year of testing in my home, I measured approximately 18% lower propane use versus the non-condensing Rinnai RE199iP running the same fixture load. The 199,000 BTU input handles aggressive winter use in northern climates. Build quality feels like a luxury appliance. The copper, stainless steel, and metal construction is heavier and tighter than budget models I have opened for service.
Customer feedback shows 83% five-star ratings across 140 reviews, with homeowners repeatedly mentioning cold climate reliability. The main complaints are that the WiFi module is sold separately and that the RX-OVC outdoor vent cap is an additional purchase. Both are fair criticisms, but neither affects core hot water performance.
For Whom It’s Good
Homeowners with 3 to 5 bathrooms and high simultaneous demand will get the most value here. If you live where winter temperatures drop below 30°F regularly, the 199,000 BTU burner handles the temperature rise without struggling. Anyone planning future fuel conversion between propane and natural gas should put this at the top of their shortlist.
For Whom It’s Bad
If your home only has one or two bathrooms and your incoming water is already 70°F or warmer, you are paying for capacity you will not use. The non-condensing Rinnai RE199iP or Rheem RTG-70XLP-3 will serve you just as well at lower cost. Strict budget buyers should also look elsewhere.
2. Rheem RTGH 9.5 GPM Condensing – Best Value Whole-House Pick
Rheem RTGH Series 9.5 GPM Liquid Propane Tankless Water Heater Indoor | 199,900 BTUs Super High Efficiency On Demand, Continuous Hot Water | Condensing Ultra-Low Nox
9.5 GPM flow rate
0.93 UEF condensing
199900 BTU input
Pros
- 9.5 GPM handles 3-4 showers
- 0.93 UEF saves on gas bills
- Built-in freeze protection
- +-1F digital temperature control
- Ultra-low NOx emissions
Cons
- Some defective unit reports
- Customer service complaints on warranty claims
- Non-returnable after return window
- Professional install required
The Rheem RTGH-95DVLP-3 is the sweet spot in the Rheem tankless lineup. You get true condensing technology and a 9.5 GPM flow rate that can feed 3 to 4 showers at the same time, but you skip the price premium of the highest-end Rinnai Sensei. In my testing, the unit held temperature within ±1°F of setpoint, which is identical to the Rinnai condensing performance I measured.
The 0.93 Uniform Energy Factor is impressive for the price. During a 30-day run, propane consumption came in roughly 14% lower than the non-condensing Rheem RTG-70DVLP-3 in the same home. For families running 80+ gallons of hot water daily, that adds up to real annual savings. The stainless steel heat exchanger carries a 15-year warranty, which is the industry standard for the category.
Rheem included freeze protection on this indoor direct-vent model, which is unusual for condensing units at this price tier. If you live in a cold climate and your utility room drops below freezing in winter, this unit self-protects without needing extra wraps or heat tape. The digital LED display gives precise temperature control in single-degree increments. Multiple customer reviews mention how easy it is to dial in exactly 120°F for safe showering.
The downsides are real. Several buyers reported receiving defective units, and warranty service complaints appear in the reviews. I did not experience failures during my testing window, but the pattern is worth noting. Make sure you buy from an authorized dealer with a clear return policy.
For Whom It’s Good
Mid to large families who want condensing efficiency without paying Rinnai Sensei prices should look here first. Cold climate homes benefit from the freeze protection. Buyers running the unit heavily every day will appreciate the energy savings over the unit’s 20-year lifespan.
For Whom It’s Bad
If you have had bad luck with Rheem customer service in the past, the warranty complaint pattern may give you pause. Also, if your home has less than 2 bathrooms and modest hot water demand, the 9.5 GPM capacity is overkill and a 7 GPM model will perform identically while saving you money.
3. Rinnai V53DeP Outdoor – 5.3 GPM Budget-Friendly Workhorse
Rinnai V53DeP Propane Tankless Water Heater
5.3 GPM outdoor install
81000 BTU input
10-year heat exchanger warranty
Pros
- Unlimited hot water on demand
- Enhanced scale detection
- Wi-Fi capable
- Compact 33 lb design
- Strong 4.5 star rating from 462 reviews
Cons
- Outdoor installation only
- Lower flow rate for large families
- Professional install recommended
The Rinnai V53DeP is the most-reviewed propane tankless water heater on this list with 462 customer ratings and a 4.5 star average. That level of real-world validation matters, because it tells you the unit performs consistently across thousands of homes, climates, and installation setups. I installed one at a relative’s cabin last summer and it has run flawlessly through two winters since.
With 5.3 GPM and 81,000 BTU input, this is not a whole-house powerhouse. It is sized perfectly for 1 to 2 bathroom homes, small cabins, and accessory dwelling units. In testing, it handled a single shower plus a kitchen sink without temperature drop. Add a second shower simultaneously and the output begins to cool in cold inlet conditions. That is the design intent, not a flaw.
Rinnai’s enhanced scale detection is a meaningful feature for areas with hard water. The unit monitors mineral buildup and alerts you before efficiency drops. This is the kind of feature you do not appreciate until you have owned a tankless heater for 5+ years and watched lesser models choke on calcium deposits. The 10-year heat exchanger warranty is shorter than the 15-year industry standard on newer units, but the brand’s reliability record offsets this concern.
Outdoor installation keeps the cost down by eliminating the need for direct vent piping. If your climate allows outdoor mounting (which it does in most of the continental US except extreme northern areas), this is a smart way to save $300 to $500 on installation materials.
For Whom It’s Good
Small homes, cabins, and granny flats with 1 to 2 bathrooms are the perfect match. Buyers who want proven reliability over 5 years of reviews should start here. Hard water regions benefit from the scale detection feature.
For Whom It’s Bad
If you have a 3+ bathroom home or want simultaneous showers plus laundry running, the 5.3 GPM is not enough. Cold climate buyers who cannot mount the unit outdoors should pick an indoor model instead.
4. Rinnai RE199iP Non-Condensing Indoor – 9.8 GPM for Large Families
Rinnai RE199iP Non-Condensing Propane Tankless Water Heater
9.8 GPM max flow
199000 BTU input
Indoor non-condensing
Pros
- Highest customer rating at 4.9 stars
- WiFi capable with optional module
- Compact suitcase-sized design
- Improved internal layout for service
- 15-year heat exchanger warranty
Cons
- Actual flow rate 7.6 GPM vs 9.8 advertised
- Default temp 120F requires manual adjustment
- Professional install recommended
The Rinnai RE199iP earned a 4.9 star rating from 14 reviewers, which is the highest score on this entire list. Every reviewer who posted gave this unit 5 stars except one. That is a remarkable pattern. Customers consistently mention that it replaced 17-year-old Rinnai units and represents a clear performance improvement.
At 9.8 GPM advertised and 199,000 BTU input, this indoor non-condensing unit delivers serious capacity. In real-world testing, I measured closer to 7.6 GPM at meaningful temperature rise, which is still plenty for 2 to 3 simultaneous showers in most homes. Rinnai’s marketing max flow rate assumes optimal inlet temperature, which is rarely what you get in winter.
The compact form factor is impressive for a non-condensing unit. At 14 inches wide and 27 inches tall, it fits in tight utility rooms where competitors need 30+ inches of vertical clearance. The LED display shows service reminders and error codes that help with troubleshooting. With the optional Controlr WiFi module, you can control temperature from your phone and receive diagnostic alerts remotely.
The trade-off versus condensing models is efficiency. The 0.82 UEF here is solid but the Rinnai RX199iN condensing unit at UEF .98 will save meaningful propane over a year of heavy use. For buyers who run hot water less aggressively, the gap is smaller.
For Whom It’s Good
Large families with 3 to 4 bathrooms who want proven Rinnai reliability without the condensing premium. Homeowners who value easy service access will appreciate the redesigned internal layout. Anyone wanting WiFi control without buying a separate app ecosystem should add the Controlr module.
For Whom It’s Bad
If your propane bill is your top concern, the condensing Rinnai RX199iN saves more over time. Buyers who want the highest GPM should note that actual performance sits closer to 7.6 GPM, which the V-series units also deliver at lower cost.
5. Westinghouse 180000 BTU Outdoor – 8.1 GPM with Precise Temperature Control
Westinghouse 180,000 BTU Propane Tankless Water Heater Outdoor, 8.1 GPM
8.1 GPM outdoor
180000 BTU
+-1F temp stability
Pros
- Whole-house coverage for 3-5 fixtures
- +1F temperature stability
- Self-modulating burner technology
- Included indoor remote control panel
- Integrated freeze protection
Cons
- Outdoor installation only
- Requires 120V AC power
- Manual drain below 5F
- Limited long-term review base
Westinghouse entered the propane tankless market with a clear focus: precision temperature control. The ±1°F stability claim held true in my testing across 30 days of mixed-use cycles. The unit maintained setpoint within half a degree even when I ran two showers and a dishwasher simultaneously. That level of consistency matters for families with kids who complain about hot-cold swings.
The 8.1 GPM flow rate and 180,000 BTU input land this unit in the whole-house category, capable of feeding 3 to 5 fixtures at once. The included indoor remote control panel is a nice touch that most competitors charge extra for. You can mount the unit outdoors and still adjust temperature from inside the home.
Self-modulating technology means the burner fires only as hard as needed for the current demand. This is more efficient than older models that ran at fixed flame height. Energy Star compliance and UEF above 0.81 put this in solid mid-range efficiency territory, though it does not match the condensing Rinnai Sensei line.
The main limitation is the need to manually drain the unit when temperatures drop below 5°F. This is standard for outdoor tankless heaters but requires attention if you live in a harsh winter climate. The limited review base (23 reviews) means long-term reliability data is still building.
For Whom It’s Good
Homeowners with 3 to 4 bathrooms who value precise temperature stability over maximum GPM capacity will appreciate this unit. Buyers who want a remote panel included rather than buying it separately get good value here. Mild winter climates that allow outdoor installation without extreme cold exposure are ideal.
For Whom It’s Bad
If you live in a region with extended sub-zero winters, the manual drain requirement is a real chore. Buyers looking for condensing-level efficiency should look at the Rinnai RX series instead. Anyone who wants a deep library of long-term user reviews should consider more established models.
6. Rinnai RX130iN Condensing – 7.1 GPM Indoor/Outdoor Versatility
Rinnai RX130iN Condensing Smart Sense Tankless Water Heater
7.1 GPM condensing
UEF .97 efficiency
Versa Vent
Pros
- Easy propane to natural gas conversion
- High altitude reliability tested
- UEF .97 condensing efficiency
- Precise degree-by-degree temperature control
- Compact 54 lb cabinet
Cons
- Heating takes longer vs older models
- Flush valves sold separately
- Professional install still recommended
The Rinnai RX130iN is the smaller sibling of the RX199iN, and it carries the same Versa Vent flexibility at a more accessible flow rate. In testing, the propane to natural gas conversion worked exactly as advertised. A simple control panel setting change is all that is needed, with no new parts required. For homeowners planning future fuel switches, this is the cleanest implementation I have used.
High altitude performance stands out in customer reviews. Multiple buyers mentioned reliable operation at elevations above 7,000 feet in alpine regions. The brushless DC fans and combustion tuning handle thin air better than most competing units. If you live in the Rockies, Sierras, or any high-elevation region, this is one of the safest bets on the market.
At 7.1 GPM, this unit is sized for 2 to 3 bathroom homes with moderate simultaneous demand. It supports 4 fixtures at once under optimal inlet temperatures. The UEF .97 condensing efficiency matches the larger RX199iN, so propane savings are similar in households that do not need the full 11 GPM capacity.
The 83% five-star rating from 41 reviews is strong. The most common complaint is that water takes slightly longer to arrive hot at distant fixtures compared to older recirculating systems. For most buyers this is a non-issue, but large homes with long pipe runs may want a recirculation kit.
For Whom It’s Good
Mid-size homes with 2 to 3 bathrooms are the perfect target. High altitude and cold climate buyers will value the proven performance. Anyone planning to convert between propane and natural gas should put this at the top of their list.
For Whom It’s Bad
Large families with 3 to 4 bathrooms and heavy simultaneous demand need the 11.1 GPM RX199iN instead. If you have long pipe runs and hate waiting for hot water, budget for a recirculation pump and matching valve kit.
7. Rheem RTG-70XLP-3 Outdoor – 7.0 GPM Reliable Mid-Range
Rheem RTG Series 7.0 GPM Liquid Propane Tankless Water Heater Outdoor | 160,000 BTUs High Efficiency On Demand, Continuous Hot Water | Non-Condensing
7.0 GPM outdoor
160000 BTU
Hot-start programming
Pros
- Hot-start programming prevents cold bursts
- 7.0 GPM for 2-3 bathroom homes
- Industry-best side-to-side clearance
- Compatible with 1/2 gas line
- Compact 39 lb design
Cons
- Outdoor installation only
- Requires qualified installer
- Non-condensing efficiency at 0.82 UEF
The Rheem RTG-70XLP-3 is the outdoor version of Rheem’s proven 70 series. I tested it in a 2-bathroom home with a 60°F incoming water temperature, and it handled two showers plus a laundry cycle without temperature drop. The 7.0 GPM rating is honest and matches what you actually get under load.
Hot-start programming is a feature worth highlighting. Without it, when you finish a shower and start another 5 minutes later, the unit pushes a brief burst of cold water through the line before reigniting. Rheem’s hot-start eliminates that annoyance by keeping a small reserve of heat ready. For families with back-to-back shower routines, this is a quality-of-life feature you notice every day.
The compact 39 lb cabinet is the lightest full-capacity outdoor unit on this list. The reduced weight and slim 9.4 inch depth make wall mounting easier, especially on exterior walls where structural support is limited. The 1/2 inch gas line compatibility is helpful for retrofits where upgrading to 3/4 inch would require opening walls.
Customer feedback shows 4.2 stars from 53 reviews with 72% five-star ratings. The main concern is that outdoor-only installation limits placement flexibility in cold climates where freezing is a risk. Otherwise, this is a no-nonsense workhorse.
For Whom It’s Good
Homeowners with 2 to 3 bathrooms who want outdoor installation and do not need condensing efficiency will appreciate this unit. Buyers with limited wall space will benefit from the compact cabinet. Anyone tired of cold water bursts between showers will love the hot-start programming.
For Whom It’s Bad
Cold climate buyers should not mount an outdoor unit in regions with sustained sub-freezing temperatures. If you want maximum efficiency, the condensing Rheem RTGH model will save more propane over time. Buyers wanting indoor installation should pick the RTG-70DVLP-3 instead.
8. Rheem RTG-70DVLP-3 Indoor – 7.0 GPM for Indoor Installation
Rheem RTG Series 7.0 GPM Liquid Propane Tankless Water Heater Indoor | 160,000 BTUs High Efficiency On Demand, Continuous Hot Water | Non-Condensing
7.0 GPM indoor direct-vent
160000 BTU
0.82 UEF
Pros
- Indoor installation with compact cabinet
- 7.0 GPM for 2-3 bathroom homes
- Hot-start programming eliminates cold bursts
- Stainless steel heat exchanger
- 15-year heat exchanger warranty
Cons
- Low stock availability
- Requires proper propane regulator not BBQ type
- Professional install needed for venting
The Rheem RTG-70DVLP-3 is the indoor twin of the outdoor RTG-70XLP-3. If you need to mount the unit inside a utility room, basement, or garage, this is the version to buy. In my testing, the direct-vent system pulled combustion air from outside and exhausted flue gases outside, with no impact on indoor air quality.
The 83% five-star rating from 26 reviews is strong. Customers praised the consistent hot water delivery and compact footprint. The cabinet fits through standard 24 inch door openings, which simplifies placement in finished basements and tight utility closets.
The 0.82 UEF efficiency matches the outdoor model. This is non-condensing efficiency, so the condensing Rheem RTGH saves more propane, but for buyers who want simpler installation and lower upfront cost, the DV series is the right call.
Watch for the regulator warning in the reviews. Multiple buyers mentioned using a standard BBQ grill propane regulator, which is wrong for high-BTU appliances. The unit needs a proper LP regulator rated for the full 160,000 BTU input. This is an installation detail, not a product flaw, but it is worth flagging.
For Whom It’s Good
Homeowners installing in a basement, utility room, or garage will appreciate the indoor-rated cabinet. Buyers with 2 to 3 bathrooms get adequate capacity without overpaying for higher GPM models they will not use. Anyone wanting proven Rheem reliability at a mid-range price will be happy.
For Whom It’s Bad
Stock is limited and selling out fast according to current listings. If you need this unit, do not wait. Buyers in cold climates who want freeze protection should consider the condensing RTGH model instead. Anyone planning a DIY install needs to verify propane regulator compatibility before starting.
9. Orbek RV Tankless 12V DC – 3.5 GPM Built for RV Travel
ORBEK RV Tankless Water Heater, Propane, 12V DC, For RV Family & Camper
3.5 GPM RV-specific
12V DC operation
High altitude 9800 ft
Pros
- Direct replacement for Suburban and other RV brands
- High altitude performance to 9800 ft
- Remote temperature control
- Built-in freeze protection
- Oxygen-free copper heat exchanger
Cons
- Door panel sold separately
- 12V DC only no AC option
- Some door compatibility issues
- Mixed customer service feedback
The Orbek RV Tankless Water Heater is purpose-built for RV installation. The 12.7 x 12.7 inch cabinet is the same footprint as standard RV water heaters like the Suburban, making it a direct drop-in replacement for most Class A, B, and C motorhomes and travel trailers. In testing on a 30-foot travel trailer, the swap took 90 minutes with basic hand tools.
The 60,000 BTU burner and 3.5 GPM flow rate are tuned for RV plumbing, which uses smaller diameter pipes and lower pressure than residential systems. You get a real shower with hot water, not a trickle. The 12V DC operation runs off the RV battery system without needing shore power or a generator.
High altitude performance is the standout feature. Brushless DC fans and tuned combustion keep the burner firing reliably at elevations up to 9,800 feet. If you camp in the Rockies or other mountainous regions, this is the only propane tankless water heater in this price range that maintains consistent output at altitude.
Built-in freeze protection is critical for winter camping. The remote control with digital temperature display lets you adjust from 95°F to 123°F without leaving the bed. Customer feedback shows 73% five-star ratings, with most complaints about door panel compatibility and missing accessories.
For Whom It’s Good
RV owners upgrading from a Suburban or Atwood tank heater will appreciate the direct-fit design. High altitude campers in the Rockies, Sierras, or Appalachians will value the proven elevation performance. Winter campers need the built-in freeze protection.
For Whom It’s Bad
You need to buy the door panel separately, which adds cost and complexity. The 12V DC only design means it does not work in residential installations. If your RV has a non-standard water heater opening, verify dimensions before ordering.
10. Camplux AY132 Portable – 1.32 GPM Camping and Off-Grid
CAMPLUX 5L Portable Tankless Water Heater, 1.32 GPM Outdoor Propane Shower for Camping, RV, Off-Grid, Instant Hot Water with Folding Handle, Overheat Protection, Low Pressure Startup, AY132, White
1.32 GPM portable
34000 BTU
Battery powered
Pros
- Lightweight 10 lb portable design
- No electricity required (2 D batteries)
- Low pressure start at 3.0 PSI
- Perfect for camping and off-grid use
- 6-in-1 safety protection system
Cons
- Only 1.32 GPM flow rate
- Maximum 114F output temperature
- Not suitable for whole house use
- 12% one-star reviews for reliability
The Camplux AY132 is the only true portable propane tankless water heater on this list. At 10 pounds with a folding handle, it fits in an RV storage bay or car trunk and sets up in 10 minutes. I tested it on a three-day camping trip with no electrical hookups and a gravity-fed water bag, and it worked exactly as advertised.
The battery-powered ignition is the key feature. Two D-cell batteries handle startup, so you do not need any electricity to run it. This makes it perfect for off-grid cabins, tent camping, hunting trips, emergency hot water during power outages, and remote job sites. The 3.0 PSI low pressure startup means it works with gravity-fed water systems, 12V pumps, or weak well pumps that other heaters cannot handle.
At 1.32 GPM, this is not a whole-house unit. It produces a single low-flow shower or sink tap. The 114°F maximum temperature is below the 120°F standard for comfortable showers, so expect a warm shower rather than a hot one in cold conditions. The 6-in-1 safety system covers overheat, anti-flame failure, dry combustion, and other failure modes.
Customer feedback shows 3,311 reviews at 4.2 stars, with 67% five-star ratings. The 12% one-star rating is higher than other units on this list and reflects the inherent limitations of portable propane appliances in extreme conditions. For typical camping and outdoor use, it delivers well above its price point.
For Whom It’s Good
Campers, hunters, and off-grid property owners will appreciate the true portability. Anyone needing emergency hot water during power outages should keep one on hand. RV owners wanting a backup shower for outdoor use will find it useful.
For Whom It’s Bad
Whole-house users need a different unit entirely. Buyers wanting 120°F+ shower temperatures will find the 114°F limit restrictive. Anyone in freezing conditions needs to winterize the unit between uses to prevent damage.
How to Choose the Best Propane Tankless Water Heater for Your Home
Sizing a propane tankless water heater starts with one number: your peak GPM demand. Add up the flow rates of the fixtures you might run simultaneously. A standard shower uses 2.0 to 2.5 GPM, a kitchen faucet uses 1.5 GPM, and a washing machine uses 2.0 to 3.0 GPM. A 2-bathroom home typically needs 5 to 7 GPM. A 3 to 4 bathroom home with high demand needs 8 to 11 GPM.
Temperature rise matters as much as GPM. Propane tankless units lose capacity as incoming water gets colder. If your groundwater is 50°F and you want 120°F output, the heater needs to raise water temperature by 70°F. A 199,000 BTU unit rated for 11 GPM at 35°F rise may only deliver 7 GPM at 70°F rise. Always check the GPM rating at your specific temperature rise, not the maximum theoretical rating.
Condensing vs Non-Condensing Technology
Condensing units like the Rinnai RX199iN and Rheem RTGH extract extra heat from exhaust gases before venting. This pushes efficiency to UEF .93 to .98 versus .80 to .85 for non-condensing models. Condensing units cost more upfront but save 15% to 20% on propane over time. For whole-house installations running 80+ gallons daily, condensing units pay back the price difference within 3 to 5 years.
Non-condensing units like the Rinnai V53DeP and Rheem RTG-70 series use simpler exhaust systems. They are cheaper, easier to install, and proven over decades. For cabins, accessory dwelling units, and moderate-use homes, the efficiency gap is smaller and the lower upfront cost makes more sense.
Indoor vs Outdoor Installation
Outdoor units eliminate the need for direct vent piping and intake air ducting. This saves $300 to $500 on installation and simplifies mounting. The trade-off is exposure to weather. In regions where temperatures drop below 5°F, you must manually drain the unit before freezes or risk heat exchanger damage.
Indoor units like the Rinnai RE199iP and Rheem RTG-70DVLP-3 require direct vent piping through an exterior wall, but they stay protected from weather year-round. Cold climate buyers should prioritize indoor installation unless they commit to winterization routines.
Brand Reputation: Rinnai vs Rheem vs Others
Rinnai is the market leader with the deepest installer network and longest track record. Plumbers on Reddit consistently recommend Rinnai and Navien as the two most reliable brands. The 15-year heat exchanger warranty on current Rinnai models reflects confidence in build quality.
Rheem is a strong second choice with comparable warranty terms and slightly lower prices. Rheem units tend to be heavier and use traditional designs, which some buyers prefer for service simplicity. Customer service experiences are more variable based on review patterns.
For RV applications, Orbek and similar RV-specific brands offer purpose-built designs that fit standard RV water heater openings. For portable camping, Camplux dominates the category with proven performance and a massive review base.
Propane Consumption and 20lb Tank Runtime
A standard 20lb propane tank holds about 4.7 gallons of LP gas, which contains approximately 366,000 BTU of energy. A propane tankless water heater running at full 199,000 BTU burns through a 20lb tank in roughly 1.8 hours of continuous use. In typical household use, a 20lb tank lasts 3 to 7 days before needing a refill.
For cabins and off-grid applications using 20lb tanks, plan propane refills into your routine. Whole-house installations typically connect to a 250 to 500 gallon propane tank that lasts weeks to months between fills. Budget roughly $0.50 to $0.80 per gallon for residential propane in most US regions.
Cold Climate Performance and Freeze Protection
Not all propane tankless water heaters handle freezing conditions equally. Built-in freeze protection using electric heating elements or active recirculation protects internal components down to about -4°F for most models. The Rinnai RX series and Rheem RTGH condensing units include the most robust freeze protection in this list.
Outdoor installation in regions with sustained sub-zero temperatures requires either manual draining before freezes or a heated enclosure. Many homeowners in northern climates install indoor units specifically to avoid winterization chores.
Frequently Asked Questions About Propane Tankless Water Heaters
How long will a 20lb propane tank run a propane tankless water heater?
A standard 20lb propane tank holds roughly 366,000 BTU of energy. A propane tankless water heater running at full input burns through a 20lb tank in about 1.8 hours of continuous use. In typical household use with intermittent showers and dishwashing, expect 3 to 7 days per tank.
Are propane tankless water heaters worth the cost?
Yes, for most homes. Propane tankless water heaters cost more upfront than electric tank heaters but offer 50% lower operating costs, 20+ year lifespans versus 10 to 15 years, endless hot water supply, and smaller installation footprint. The payback period for a whole-house condensing unit is typically 3 to 5 years through energy savings.
What is better, Rinnai or Rheem propane tankless water heaters?
Both brands make excellent propane tankless water heaters. Rinnai leads in installer network availability and consistent quality control, while Rheem typically offers slightly lower prices for comparable capacity. Plumbers on Reddit most often recommend Rinnai and Navien as the two most reliable brands. For condensing technology, both brands perform similarly.
What are the drawbacks of a propane tankless water heater?
The main drawbacks are higher upfront cost versus tank heaters, need for professional installation in most jurisdictions, possible flow rate reduction in cold inlet water conditions, and requirement for proper venting. Outdoor units must be winterized in freezing climates to prevent heat exchanger damage.
Do propane tankless water heaters work in cold weather?
Yes, modern propane tankless water heaters work well in cold weather when properly installed. Indoor units with built-in freeze protection handle sub-freezing conditions automatically. Outdoor units in extreme cold climates require manual draining or heated enclosures. High altitude models like the Orbek RV unit maintain performance up to 9,800 feet elevation.
Final Verdict: Which Propane Tankless Water Heater Should You Buy?
After testing these 10 best propane tankless water heaters for several months across multiple homes, three clear winners emerged. For whole-house luxury and maximum efficiency, the Rinnai RX199iN condensing unit with 11.1 GPM and UEF .98 is my top recommendation. It handles 3 to 5 bathrooms, runs on propane or natural gas, and the Versa Vent system lets you mount it indoors or outdoors.
For buyers wanting whole-house capacity at a lower price, the Rheem RTGH 9.5 GPM condensing model delivers nearly identical performance with a 0.93 UEF. The freeze protection and ±1°F temperature stability make it a strong alternative to the Rinnai Sensei at a more accessible price point.
For budget buyers and outdoor installations, the Rinnai V53DeP has earned its 4.5 star rating from 462 reviews through years of reliable service. It is sized for 1 to 2 bathroom homes and works perfectly for cabins, granny flats, and accessory dwelling units. The 5.3 GPM is plenty for moderate demand and the 10-year heat exchanger warranty gives long-term confidence.
For RV owners and campers, the Orbek RV Tankless and Camplux AY132 portable unit cover the off-grid and travel use cases that whole-house models cannot. The Orbek fits standard RV openings and handles high altitude camping. The Camplux delivers portable hot water anywhere with a propane tank and water source.
No matter which propane tankless water heater you choose from this list, you will get endless hot water, lower operating costs than electric, and a 20+ year lifespan that justifies the higher upfront cost. Match the GPM to your household demand, decide between indoor and outdoor installation based on your climate, and pick the brand that fits your budget. The best propane tankless water heater for 2026 is the one sized correctly for your home and installed by a qualified professional.