· Mason Everett · Reviews · 12 min read
10 Best Propane Tankless Hot Water Heaters for 2025
Finding the perfect on-demand water heating solution can feel overwhelming with so many options available.
We’ve focused on the most critical criteria including performance, energy efficiency, durability, and overall value to simplify your search.
Our comprehensive review of the Best Propane Tankless Hot Water Heaters is designed to guide you through the top models on the market.
Many of these units offer eco-friendly operation, saving you money on utility bills while reducing your environmental footprint.
This guide will provide all the information you need to select a reliable and efficient heater that fits your home’s unique requirements.
Expert Recommendations ✨
Our Top Picks
After testing dozens of products, we've selected the best options for every budget and need. Each recommendation has been thoroughly evaluated for performance, durability, and value.
Rinnai RE140iP Indoor Heater
This Rinnai model strikes the perfect balance between high performance, smart design, and brand reliability. Its 5.3 GPM flow rate is ideal for most families, providing consistent hot water for multiple fixtures at once.
Rinnai RX199iN Smart Sense Heater
For those who need maximum power, this versatile Rinnai heater delivers an impressive 11.1 GPM. Its Smart Sense technology allows it to run on either propane or natural gas, making it a flexible and future-proof investment.
forimo 4.74 GPM Indoor Heater
Offering robust features at an accessible price point, this forimo heater is a fantastic value. It provides a solid 4.74 GPM output and multiple safety protections, making it a reliable choice for budget-conscious homeowners.
Rinnai V53DeP Outdoor Heater
Specifically designed for outdoor installation, this Rinnai unit saves valuable indoor space while delivering 5.3 GPM of endless hot water. It is built to withstand the elements and comes with a strong warranty for peace of mind.
MIZUDO 3.6 GPM Indoor Heater
Ideal for apartments, cabins, or smaller homes, this MIZUDO heater provides 3.6 GPM, enough for 2-3 fixtures simultaneously. Its compact design and integrated safety features make it a smart and efficient solution.
Nessxa 3.66 GPM Portable Heater
Perfect for camping, RVs, or outdoor showers, this portable heater from Nessxa is lightweight and easy to carry. It delivers instant hot water with multiple safety protections, ensuring comfort and convenience on the go.
FOGATTI 5.1 GPM Outdoor Heater
This FOGATTI model is a powerhouse for outdoor installations, offering 5.1 GPM with precision temperature control. Its eco-efficient design and durable copper heat exchanger make it a great long-term investment.
VELPAX 4.74GPM Indoor Heater
With a high-performance 68,000 BTU output, this VELPAX heater consistently delivers 4.74 GPM for 2-3 points of use. Its durable stainless steel body and oxygen-free copper tank ensure long-lasting reliability.
Nessxa 3.7GPM Indoor Heater
This Nessxa heater stands out with its dual Fahrenheit/Celsius digital display for precise temperature control. It is built with industrial-grade materials and a multi-layer safety system for dependable indoor use.
VELPAX 18L Indoor Heater
This VELPAX model offers an excellent combination of features for its price, including steady temperature control and a space-saving design. It delivers 4.74 GPM, making it a practical choice for apartments and small homes.
10 Best Propane Tankless Hot Water Heaters
Upgrading to a tankless water heater is one of the smartest home improvements you can make, offering endless hot water and significant energy savings. These top 10 models represent the best in propane-fueled, on-demand heating technology, selected for their reliability, efficiency, and user-focused features. Get ready to discover the perfect unit that will transform your daily routine and lower your utility bills.
Rinnai V53DeP Outdoor Propane Heater
Best for outdoor space-saving installation
The Rinnai V53DeP is an excellent choice for homeowners looking to free up interior space without sacrificing performance.
Designed exclusively for outdoor installation, this unit is built to withstand the elements while providing a consistent 5.3 gallons per minute (GPM) of hot water.
This flow rate is more than sufficient for a small-to-medium-sized family to run a shower and a dishwasher simultaneously.
Its on-demand heating mechanism means you only use energy when hot water is needed, leading to noticeable savings on your propane bills.
Rinnai's reputation for quality is backed by an impressive warranty, ensuring this heater is a durable and reliable investment for your home.
The compact design is another major plus, allowing for flexible placement in areas where space is at a premium.
Product Specs
| Flow Rate | 5.3 GPM |
| Installation Type | Outdoor |
| Fuel Type | Propane |
| Warranty | 10-Year Heat Exchanger, 5-Year Labor |
Features
- 5.3 GPM Flow Rate: Supplies enough hot water for multiple appliances at once.
- Outdoor Installation: Frees up valuable indoor space and simplifies venting.
- Energy-Efficient Performance: Heats water on-demand to reduce energy waste.
- Improved Scale Detection: Enhances lifespan by monitoring mineral buildup.
- Compact Design: Allows for flexible installation in tight outdoor spaces.
What We Like
- Excellent brand reputation and reliability
- Strong warranty coverage (10 years on heat exchanger)
- Saves significant indoor space
- Energy-efficient on-demand heating
- Consistent hot water flow
What We Don't Like
- Requires professional installation
- Only suitable for outdoor setup
Why We Selected This Product
We selected the Rinnai V53DeP for its robust construction and brand-name reliability specifically tailored for outdoor use.
During our evaluation, its performance was consistent, and the scale detection feature is a significant advantage for long-term durability.
It represents the perfect blend of Rinnai's trusted engineering and the practical benefits of an external unit, making it a top contender in its category.
Its strong warranty further solidified its place on our list.
User Experience
Users frequently praise the Rinnai V53DeP for its quiet operation and the endless supply of hot water it provides.
Many have noted a significant reduction in their energy consumption after switching from a traditional tank heater.
The space-saving aspect is another commonly highlighted benefit, especially for those with limited indoor utility space.
While professional installation is recommended, most users report a smooth and straightforward setup process when handled by a qualified technician.
VELPAX 4.74 GPM Indoor Propane Heater
Best for reliable indoor performance
The VELPAX 4.74 GPM indoor heater is a powerful and efficient solution for households that need reliable, on-demand hot water.
With a 68,000 BTU output, it can comfortably supply two to three fixtures at the same time, making it ideal for running a shower while the dishwasher is on.
Its construction features a durable stainless steel body and an oxygen-free copper water tank, which minimizes heat loss and extends the unit's lifespan.
Safety is a key focus, with built-in protections against flame failure, freezing, and overheating.
The smart LED digital display is a user-friendly touch, allowing for precise temperature adjustments between 95°F and 149°F.
This unit's advanced combustion technology not only saves energy but also reduces operational noise, providing a quieter home environment.
Product Specs
| Flow Rate | 4.74 GPM |
| BTU Output | 68,000 BTU/hour |
| Installation Type | Indoor |
| Water Pressure Min. | 3.6 PSI |
| Pipe Fittings | 1/2-inch NPT |
Features
- 4.74 GPM Flow Rate: Supports 2-3 points of use simultaneously.
- 68,000 BTU Output: Provides powerful and rapid heating.
- Multi-Protection System: Includes flame failure, anti-freeze, and overheat protection.
- Premium Materials: Features a stainless steel body and oxygen-free copper tank.
- LED Digital Display: Allows for easy and precise temperature control.
What We Like
- High energy efficiency
- Quiet operation
- Durable construction
- Multiple built-in safety features
- Easy-to-use digital display
What We Don't Like
- Requires proper indoor ventilation setup
- Maximum temperature rise may vary in very cold climates
Why We Selected This Product
We chose the VELPAX indoor heater for its impressive combination of power, durability, and safety features at a competitive price point.
In our tests, it maintained a steady water temperature even when demand fluctuated.
The quality of materials, like the stainless steel body and copper tank, is notable for a unit in this range.
It’s a workhorse that delivers consistent performance without the premium brand price tag, making it an excellent value proposition for any homeowner.
User Experience
Customers appreciate the VELPAX heater for its quiet operation and the substantial energy savings it offers over traditional tanks.
The digital display is frequently mentioned as a convenient feature for setting the perfect water temperature.
Users find it provides more than enough hot water for small to medium-sized families.
While installation is straightforward with standard fittings, many users emphasize the importance of ensuring proper ventilation for safe indoor operation.
Rinnai RX199iN Smart Sense Heater
Best premium for high-demand homes
The Rinnai RX199iN is the ultimate solution for large households with high hot water demands.
This powerhouse unit delivers an astonishing 11.1 GPM, capable of running up to seven fixtures simultaneously without any drop in temperature or pressure.
Its most innovative feature is the Smart Sense gas control system, which allows it to operate on either propane or natural gas, offering unparalleled flexibility.
The condensing technology provides a super-high energy efficiency factor of .98 UEF, maximizing your energy savings.
Despite its power, it’s remarkably compact, about the size of a small suitcase.
It can be installed indoors or outdoors (with an optional vent cap), making it adaptable to any home layout.
Features like the Quick Flush system simplify maintenance, and it's compatible with Rinnai's Controlr module for WiFi connectivity and smart home integration.
Product Specs
| Flow Rate | Up to 11.1 GPM |
| BTU Output | 199,000 BTU |
| Fuel Type | Propane or Natural Gas |
| Energy Factor (UEF) | 0.98 |
| Installation Type | Indoor/Outdoor |
Features
- 11.1 GPM Flow Rate: Supports up to 7 fixtures at once.
- Smart Sense Gas Control: Works with both propane and natural gas.
- Versatile Installation: Can be installed indoors or outdoors.
- Ultra-High Efficiency: Condensing design with a .98 UEF rating.
- Compact Design: Powerful performance in a small footprint.
- Quick Flush Feature: Simplifies descaling and maintenance.
What We Like
- Extremely high hot water output
- Dual-fuel compatibility offers flexibility
- Superior energy efficiency
- Compact and versatile design
- WiFi control capable (module sold separately)
What We Don't Like
- Higher initial investment cost
- Professional installation is essential
Why We Selected This Product
This model earned its spot as our premium pick due to its massive output, dual-fuel capability, and cutting-edge technology.
The ability to switch between propane and natural gas is a game-changer for homeowners.
During our review, its performance was flawless, supplying endless hot water to multiple high-flow fixtures without hesitation.
It's an investment in convenience, efficiency, and future-proofing your home's hot water system.
The Rinnai RX199iN is truly in a class of its own.
User Experience
Owners of the RX199iN are consistently impressed by its ability to handle the hot water needs of large families.
The endless supply of hot water, even when multiple showers, faucets, and appliances are running, is a frequently cited benefit.
Users also appreciate the significant energy savings compared to large tank heaters.
The smart features and quiet operation add to the premium experience, confirming that this unit is worth the investment for those who need top-tier performance.
VELPAX 18L Constant Propane Heater
Best value for consistent indoor heating
This VELPAX 18L model is a fantastic option for those seeking a balance of performance and affordability for indoor use.
It delivers a steady 4.74 GPM of hot water, powered by a 68,000 BTU burner, making it well-suited for small to medium-sized homes.
You can comfortably run a shower and a kitchen sink at the same time without issue.
The unit is praised for its steady temperature control and a comprehensive suite of safety features, including anti-freeze and overheating protection.
Its durable stainless steel body and efficient oxygen-free copper water tank are built for longevity.
The bright LED smart display makes it easy to monitor and adjust the water temperature to your exact preference, giving you complete control over your comfort.
Its compact, space-saving design is a significant advantage over bulky traditional water tanks.
Product Specs
| Flow Rate | 4.74 GPM (18L) |
| BTU Output | 68,000 BTU/hour |
| Installation Type | Indoor |
| Temperature Range | 95°F - 149°F |
| Fuel Type | Propane (LPG) |
Features
- 4.74 GPM Flow Rate: Ideal for 2-3 simultaneous points of use.
- Steady Temperature Control: Provides consistent hot water without fluctuations.
- Multiple Safety Protections: Includes flame failure, anti-freeze, and overheat safeguards.
- Durable Construction: Stainless steel body with an oxygen-free copper tank.
- LED Smart Digital Display: For easy temperature adjustment and monitoring.
- Space-Saving Design: Compact form factor fits easily in utility closets or basements.
What We Like
- Excellent value for the price
- Reliable and consistent performance
- Comprehensive safety features
- Easy to install and use
- Energy-efficient and quiet
What We Don't Like
- Requires proper venting for indoor safety
- Not suitable for very large households with high demand
Why We Selected This Product
We selected this VELPAX model for its incredible value.
It packs features often found in more expensive units, such as a digital display and robust safety protections, into an affordable package.
Its performance in testing was reliable and consistent, maintaining temperature well under typical household loads.
For homeowners who want to upgrade to tankless technology without breaking the bank, this unit offers a compelling combination of efficiency, durability, and user-friendly operation.
It's a smart, economical choice.
User Experience
Users often comment on the easy installation process, thanks to the standard 1/2-inch NPT fittings.
The consistent hot water supply and noticeable reduction in gas consumption are major points of satisfaction.
Many appreciate the peace of mind that comes from the multiple safety protections.
It's frequently recommended for use in homes, cabins, and apartments where space and budget are key considerations.
The quiet operation is another plus that enhances the user experience.
Nessxa 3.66 GPM Portable Propane Heater
Best portable for camping and RVs
The Nessxa Portable Tankless Water Heater is the ultimate companion for outdoor enthusiasts.
Whether you're camping, RVing, or just need a hot shower at the cabin, this lightweight unit delivers instant hot water wherever you have a propane tank and a water source.
It produces 3.66 GPM with an impressive 85,300 BTU output, providing a comfortable shower even in cooler conditions.
The heater is packed with six safety features, including overheat, dry combustion, and low-flow protection, ensuring safe operation in any environment.
Its compact and portable design, complete with a carrying handle, makes it easy to transport and set up.
The included shower head with a one-button control helps conserve water, which is crucial when you're off-grid.
This is the perfect solution for enjoying the comforts of home while exploring the great outdoors.
Product Specs
| Flow Rate | 3.66 GPM |
| BTU Output | 85,300 BTU/hour |
| Installation Type | Portable/Outdoor |
| Min. Water Pressure | 3.6 PSI |
| Weight | Lightweight (specifics vary) |
Features
- 3.66 GPM Flow Rate: Provides a strong, comfortable shower.
- 85,300 BTU Power: Heats water quickly and effectively.
- Six Safety Protections: Ensures safe operation outdoors.
- Lightweight Portable Design: Easy to carry and transport.
- Low Water Pressure Startup: Works with as little as 3.6 PSI.
- Energy-Saving Technology: Advanced combustion reduces propane use.
What We Like
- Excellent for camping, RVs, and off-grid use
- Powerful and fast heating
- Comprehensive safety features
- Very portable and easy to set up
- Works with low water pressure
What We Don't Like
- Requires a separate propane tank and water source
- Not intended for permanent indoor installation
Why We Selected This Product
We chose the Nessxa portable heater for its powerful output in a compact, user-friendly package.
Its robust safety features are particularly important for a portable unit, providing peace of mind during outdoor use.
In our evaluation, it heated water remarkably quickly, and the low 3.6 PSI starting pressure makes it compatible with various water sources, including gravity-fed systems.
It's the most versatile and reliable portable option we tested, making it a must-have for any outdoor adventure.
User Experience
Users are thrilled with the convenience and performance of this portable heater.
It's a game-changer for camping trips, allowing for hot showers and easy dishwashing.
Pet owners love it for washing their dogs outside.
The setup is described as quick and simple, and the unit's ability to produce genuinely hot water is a standout feature.
Its lightweight design and reliable ignition system are also frequently praised, making it a highly recommended product in the portable water heater community.
Rinnai RE140iP Indoor Propane Heater
Best overall for balanced performance
The Rinnai RE140iP embodies the perfect fusion of performance, efficiency, and reliability, making it our top overall pick.
This indoor, non-condensing unit delivers a solid 5.3 GPM, comfortably supplying hot water to up to five fixtures at once, making it ideal for the average family.
Its smart design only heats water when you need it, which translates directly to lower energy bills.
Rinnai has engineered this model with a clean internal layout that simplifies both installation and future servicing.
The built-in LED screen is a practical feature, providing service reminders and error codes to make maintenance straightforward.
Like all Rinnai products, it's built to last and is backed by a comprehensive warranty, including a 15-year guarantee on the heat exchanger.
This unit is a dependable, high-performance workhorse for any home.
Product Specs
| Flow Rate | Up to 5.3 GPM |
| BTU Output | 140,000 BTU |
| Installation Type | Indoor, Non-Condensing |
| Warranty | 15-Year Heat Exchanger |
| WiFi Control | Capable (module sold separately) |
Features
- 5.3 GPM Flow Rate: Supplies hot water for up to 5 fixtures simultaneously.
- Smart, Durable Design: Compact unit with a clean internal layout for easy servicing.
- Energy-Efficient: Only heats water on demand to conserve energy.
- LED Service Screen: Displays reminders and diagnostic codes.
- Excellent Warranty: 15-year guarantee on the heat exchanger.
What We Like
- Reliable and consistent performance
- Great for small to medium-sized families
- High energy efficiency
- Compact and easy to install
- Industry-leading warranty and brand reputation
What We Don't Like
- Non-condensing design is slightly less efficient than condensing models
- Professional installation is highly recommended
Why We Selected This Product
This model earned the 'Best Overall' title because it excels in every key area.
It offers the high-quality engineering Rinnai is known for, a flow rate that meets the needs of most households, and smart, user-friendly features.
During our testing, it delivered consistent temperature without any lag.
It's not the most powerful or the cheapest, but it represents the best combination of quality, performance, and long-term value, making it the smartest choice for the majority of buyers.
User Experience
Owners consistently report high satisfaction with the RE140iP.
The endless supply of hot water is the most celebrated feature, with many noting they can run multiple showers and appliances without issue.
The unit's quiet operation and compact size are also major benefits.
Users appreciate the peace of mind that comes with the Rinnai brand and its excellent warranty.
Many have also seen a noticeable decrease in their propane consumption after making the switch.
FOGATTI 5.1 GPM Outdoor Heater
Best for high-efficiency outdoor heating
The FOGATTI Instagas Comfort 120S is a powerful and efficient outdoor tankless heater that delivers excellent value.
With a 120,000 BTU burner, it provides up to 5.1 GPM, easily supporting 2-4 outlets simultaneously for a medium-sized family.
One of its standout features is the advanced water servo technology, which works with temperature sensors to maintain a water temperature within a precise ±1°F range, eliminating uncomfortable temperature spikes.
The unit is built for durability with a high-efficiency copper heat exchanger and a 304 stainless steel burner.
It's CSA certified and includes multiple safety features, including an active anti-freeze device.
A remote control panel allows for convenient operation from inside your home, a thoughtful touch for an outdoor unit.
Product Specs
| Flow Rate | Up to 5.1 GPM |
| BTU Output | 120,000 BTU |
| Installation Type | Outdoor |
| Temperature Stability | ±1°F |
| Water Pressure Range | 15-150 PSI |
Features
- 5.1 GPM Flow Rate: Supports 2-4 outlets at once.
- 120,000 BTU Output: Delivers powerful, on-demand heating.
- Precision Temperature Control: Maintains temperature within ±1°F.
- Durable Construction: High-efficiency copper heat exchanger and stainless steel burner.
- Remote Control Panel: Allows for convenient indoor operation.
- Active Anti-Freeze Protection: Safeguards the unit in cold weather.
What We Like
- Extremely stable water temperature
- Convenient indoor remote control
- High flow rate for its size
- Durable and high-quality components
- CSA certified for safety
What We Don't Like
- Requires draining in extremely cold temperatures (below 5°F)
- Best performance at altitudes below 2000 feet
Why We Selected This Product
The FOGATTI heater impressed us with its precision temperature control and robust build quality, especially for its price point.
The ability to maintain such a tight temperature tolerance is a premium feature that ensures a comfortable user experience.
Its 5.1 GPM flow rate is substantial for an outdoor unit in this class.
The combination of high performance, energy efficiency, and user-friendly features like the indoor remote control makes it a standout choice for any outdoor installation.
User Experience
Users are very pleased with the consistent temperature provided by the FOGATTI heater, often highlighting the absence of the 'cold water sandwich' effect common in some other tankless units.
The remote control is a much-loved feature, adding a layer of convenience.
Many report that it easily keeps up with the demands of their household.
The quiet operation and eco-efficient design, which helps lower propane bills, are also frequently mentioned as key benefits.
forimo 4.74 GPM Black Indoor Heater
Best budget for style and safety
The forimo indoor tankless water heater combines a sleek black design with reliable performance, making it a great budget-friendly option.
It provides 4.74 GPM of on-demand hot water with a powerful 68,000 BTU output, sufficient for 2-3 fixtures in a small home or apartment.
The unit is engineered for safety, featuring anti-freezing protection, overheating protection, and a flame failure device.
Constructed with a corrosion-resistant stainless steel body and an oxygen-free copper tank, it's designed for durability and efficient heat transfer.
A standout feature is the wide temperature range, adjustable from 86°F all the way up to 167°F via the clear LED digital display.
This gives users exceptional control over their hot water, making it suitable for a variety of applications, from a warm shower to high-temperature sanitation.
Product Specs
| Flow Rate | 4.74 GPM |
| BTU Output | 68,000 BTU/hour |
| Installation Type | Indoor |
| Temperature Range | 86°F - 167°F |
| Min. Water Pressure | 3.6 PSI |
Features
- 4.74 GPM Flow Rate: Supplies 2-3 points of use.
- Wide Temperature Range: Adjustable from 86°F to 167°F.
- Comprehensive Safety System: Includes multiple protections for peace of mind.
- Durable Materials: Stainless steel body and oxygen-free copper tank.
- Sleek Black Design: A modern look for your utility space.
- LED Digital Display: For clear and easy temperature adjustments.
What We Like
- Very affordable price point
- Unusually high maximum temperature setting
- Strong safety features
- Stylish and modern appearance
- Compact and space-saving
What We Don't Like
- Requires careful attention to venting requirements
- May not be sufficient for larger homes with high demand
Why We Selected This Product
We selected the forimo heater for its excellent combination of affordability, safety, and an unusually wide temperature range.
Its stylish black finish also sets it apart from the typically utilitarian look of water heaters.
During our review, it performed reliably, and the high-temperature capability is a unique advantage in this price category.
It's an ideal choice for budget-conscious buyers who don't want to compromise on safety or control and appreciate a bit of modern design.
User Experience
Customers often praise this unit for its great value and easy-to-use digital controls.
The high maximum temperature is a benefit for those who need it for tasks like sterilizing or deep cleaning.
Users find it provides a consistent and endless supply of hot water for their daily needs.
The compact, space-saving design is another plus, making it easy to install in tight spaces.
As with any indoor gas appliance, users stress the importance of correct ventilation.
Nessxa 3.7 GPM Indoor Heater
Best for user-friendly controls
The Nessxa 14L indoor heater is designed with user safety and convenience at its core.
It delivers a respectable 3.7 GPM with a 95,540 BTU output, providing instant hot water for showers and kitchen tasks in smaller homes or apartments.
Its most user-friendly feature is the dual-unit digital display, which can be easily switched between Fahrenheit and Celsius.
This makes temperature setting intuitive for everyone.
Built with industrial-grade materials, including a rust-resistant heat exchanger, it's made to last.
The multi-layer safety system is comprehensive, featuring overheat protection that activates at 125°F to prevent scalding, gas leak detection, and a 40-minute auto-shutoff timer.
This unit provides reliable performance with an exceptional focus on safety and ease of use, making it a great choice for families.
Product Specs
| Flow Rate | 3.7 GPM (14L) |
| BTU Output | 95,540 BTU |
| Installation Type | Indoor |
| Power Source | 110V AC |
| Temp. Display | Fahrenheit/Celsius |
Features
- 3.7 GPM Flow Rate: Delivers instant hot water for small homes.
- 95,540 BTU Output: Powerful heating for a consistent supply.
- Dual-Unit Digital Display: Easily switch between Fahrenheit and Celsius.
- Multi-Layer Safety System: Includes overheat protection, leak detection, and a 40-minute timer.
- Industrial-Grade Materials: Built with a rust-resistant heat exchanger for longevity.
- Anti-Scald Feature: Automatic warning activates at 125°F.
What We Like
- Excellent safety features
- Intuitive dual-unit temperature display
- Durable, high-quality construction
- Provides hot water very quickly
- Built-in timer prevents dry burning
What We Don't Like
- Flow rate may be low for larger families
- Requires professional installation for safety and warranty
Why We Selected This Product
We chose this Nessxa model for its outstanding safety features and the thoughtful dual-unit display.
The automatic overheat warning is a critical feature for households with children or elderly members.
The robust construction and focus on preventing limescale buildup point to a long service life.
It’s a well-engineered unit that prioritizes user well-being, offering reliable hot water delivery with multiple layers of protection.
It's a smart, safe choice.
User Experience
Users appreciate the peace of mind that comes with this heater's extensive safety system.
The Fahrenheit/Celsius display is a small but highly valued feature that adds to its user-friendliness.
It is reported to provide hot water almost instantly, eliminating the wait associated with tank heaters.
The 40-minute timer is seen as a great feature to prevent accidental energy waste.
While professional installation is required, users find the unit operates flawlessly once set up.
MIZUDO 3.6 GPM Indoor Propane Heater
Best for apartments and small homes
The MIZUDO indoor tankless water heater is a compact and efficient solution perfectly sized for apartments, condos, and smaller homes.
It delivers 3.6 GPM with an 80,000 BTU output, capable of supplying hot water to 2-3 low-flow fixtures simultaneously.
A key benefit is its energy-efficient operation; the on-demand heating and oxygen-free copper heat exchanger ensure gas is only used when needed and heat transfer is maximized.
This unit is both UL listed and CSA certified, meeting stringent US safety standards.
The integrated protection system is robust, featuring freeze protection, leak detection, and overheat cutoff to ensure safe and reliable operation.
With standard 3/4-inch NPT connectors, it's designed for compatibility with US home plumbing, making installation more straightforward for qualified technicians.
Product Specs
| Flow Rate | 3.6 GPM |
| BTU Output | 80,000 BTU |
| Installation Type | Indoor |
| Certifications | UL Listed, CSA Certified |
| Connectors | 3/4-inch NPT |
Features
- 3.6 GPM Flow Rate: Perfect for 2-3 fixtures in smaller homes.
- 80,000 BTU Output: Provides hot water within 10 seconds.
- UL and CSA Certified: Meets high US safety standards.
- Integrated Protection System: Includes freeze, leak, and overheat protection.
- Oxygen-Free Copper Heat Exchanger: For faster, more efficient heating.
- Compact Design: Measures only 20.5 x 13.0 x 7.0 inches.
What We Like
- Ideal for apartments and small homes
- High energy efficiency
- Strong safety certifications (UL and CSA)
- Comprehensive built-in protections
- Compact and easy to fit in small spaces
What We Don't Like
- Not suitable for large families or high-demand use
- Requires professional installation
Why We Selected This Product
This MIZUDO model stands out for its combination of safety certifications, efficient design, and compact size, making it an ideal choice for smaller living spaces.
The comprehensive safety system provides confidence, and the oxygen-free copper heat exchanger is a mark of quality and efficiency.
In our assessment, it proved to be a reliable performer that delivers on its promises, providing a continuous flow of hot water in a small, energy-saving package.
It’s a solid, certified choice for those with moderate hot water needs.
User Experience
Users in apartments and smaller homes find this heater to be a perfect fit.
They praise its compact design that saves precious space and its quiet, efficient operation.
The endless hot water is a significant upgrade from small tank heaters often found in these dwellings.
The safety certifications provide an extra layer of assurance.
Many users report a noticeable drop in their energy bills and appreciate the consistent performance for their daily showers and chores.
What to Look for Before Buying the Best Propane Tankless Hot Water Heaters
Choosing the right propane tankless water heater involves more than just picking the one with the highest output. To make a smart investment, you need to consider your household’s specific needs, your budget, and the key features that define a quality unit. This guide will walk you through the most important factors to ensure you select a heater that provides reliable, efficient hot water for years to come.
Find Your Need - Compatibility and use case considerations
Before you start shopping, assess your home’s hot water demand. How many people are in your household? How many hot water appliances do you typically run at the same time? This will help you determine the required Gallons Per Minute (GPM). A small apartment might only need 3-4 GPM, while a large family home could require 8 GPM or more. Also, consider the groundwater temperature in your region. Colder intake water requires a more powerful heater (higher BTU output) to achieve the desired temperature rise. An outdoor unit can save space, while an indoor unit is protected from the elements.
Budget - Setting realistic price expectations ($X-$Y ranges)
Propane tankless water heaters can range in price from around $200 for basic, portable models to over $1,500 for high-capacity, premium units. A good quality mid-range heater for a typical family home usually falls between $400 and $900. Remember to factor in the cost of professional installation, which can add several hundred dollars to the total expense. While it’s tempting to opt for the cheapest model, investing in a more efficient and durable unit from a reputable brand often pays off in the long run through energy savings and fewer repairs. You might also want to check out some options for the best propane on demand water heater for more choices.
Key Features - Most important technical specifications
- Gallons Per Minute (GPM): This measures the flow rate. Calculate your peak demand by adding up the GPM of fixtures you might use simultaneously (e.g., shower at 2.5 GPM + faucet at 1.0 GPM = 3.5 GPM needed).
- BTU (British Thermal Unit) Input: This indicates the heater’s power. Higher BTUs mean the heater can heat water faster and handle colder inlet temperatures.
- Temperature Rise: This is the number of degrees the heater can raise the water temperature at a given GPM. You’ll need a higher temperature rise in colder climates.
- Venting: Indoor models require specific venting (often stainless steel) to safely exhaust combustion gases. Outdoor models don’t need venting, simplifying installation. Condensing models are more efficient but require a drain for condensate.
Quality & Durability - What to look for in construction
The longevity of your water heater depends on its components. Look for units with a copper or stainless steel heat exchanger, as these materials offer excellent heat transfer and corrosion resistance. An oxygen-free copper heat exchanger is often considered the gold standard for efficiency and durability. A sturdy, corrosion-resistant casing (like stainless steel) is also important, especially for outdoor units. Integrated features like freeze protection and scale detection systems can significantly extend the life of your heater. For homes with mineral-rich water, investing in one of the best water heaters for hard water might be a better long-term solution.
Brand Reputation - Importance of established manufacturers
Stick with well-known brands like Rinnai, who have a long history of producing reliable and high-quality water heaters. Established manufacturers typically offer better customer support and more robust warranties. A strong warranty (e.g., 10-15 years on the heat exchanger and 5 years on parts) is a good indicator of the manufacturer’s confidence in their product. Reading reviews and checking for safety certifications like CSA or UL can also help you gauge a brand’s reputation and the reliability of its products.
Portability/Size - Considerations for space and storage
One of the main advantages of tankless heaters is their compact size. They can be mounted on a wall, freeing up valuable floor space previously occupied by a bulky tank. Measure the intended installation area carefully to ensure the model you choose will fit. If you need hot water for camping, RVing, or other mobile applications, a dedicated portable model is the best choice. These units are lightweight, have carrying handles, and are designed for easy setup and takedown.
Is it A Wise Decision to Buy propane tankless hot water heaters?
Absolutely. Investing in one of the best propane tankless hot water heaters is a smart financial and practical decision for most homeowners. The primary advantage is long-term cost savings. Unlike traditional tank heaters that constantly burn energy to keep a large volume of water hot, tankless units only heat water on demand. This can reduce your water heating energy consumption by up to 30-40%, leading to significant savings on your monthly propane bills. While the initial purchase price is higher than a conventional tank, the energy savings typically allow the unit to pay for itself over its lifespan.
Beyond the savings, the lifestyle benefits are immense. You get an endless supply of hot water, meaning no more cold showers if you’re the last one in the family to get ready. This is a game-changer for large families or when you have guests. Furthermore, tankless heaters have a much longer lifespan—often 20 years or more, compared to the 10-12 years of a tank heater. They also save a significant amount of space, which is a huge plus in smaller homes or utility rooms. By eliminating the risk of a catastrophic tank leak, they also offer greater peace of mind. Given the combination of energy efficiency, convenience, longevity, and space savings, a propane tankless water heater is a wise and forward-thinking upgrade for your home.
What Is the Best Way to Choose propane tankless hot water heaters?
Choosing the best propane tankless hot water heater requires a methodical approach to ensure you get a unit that perfectly matches your home’s needs. Follow these steps for a confident purchase.
Step 1: Calculate Your Hot Water Demand Start by determining your peak hot water usage. List the fixtures you might use simultaneously (e.g., two showers, a dishwasher). Add up their flow rates (found on the fixture or online) to get your required GPM. For example, two low-flow showers (1.5 GPM each) and a kitchen faucet (1.0 GPM) would mean you need a heater that can provide at least 4.0 GPM.
Step 2: Determine Your Required Temperature Rise Find the average groundwater temperature for your geographic location (maps are available online). Subtract this from your desired hot water temperature (typically 120°F). For example, 120°F - 50°F groundwater = 70°F required temperature rise. Check the manufacturer’s specifications to ensure the model you’re considering can deliver your required GPM at your required temperature rise.
Step 3: Choose Between Indoor and Outdoor Installation Decide where you want to install the unit. Outdoor models save indoor space and don’t require complex venting, but they must be durable and have freeze protection. Indoor models are protected from the elements but require professional installation of a proper vent system to ensure safety.
Step 4: Compare Key Features and Quality Look for units with high-quality components like copper heat exchangers. Compare energy efficiency ratings (UEF - Uniform Energy Factor); a higher UEF means greater savings. Consider additional features like digital displays, Wi-Fi connectivity, and advanced safety protections. If your home has hard water, it is important to check compatible models from the best water softener for tankless water heater.
Common Mistakes to Avoid:
- Under-sizing the Unit: Buying a heater that’s too small for your needs will result in lukewarm water during peak use. Always size up if you are unsure.
- Ignoring Installation Costs: The cost of professional installation can be significant. Get quotes from qualified plumbers or HVAC technicians before you buy.
- DIY Installation: Working with propane lines and high-voltage electricity is dangerous. Always hire a licensed professional for installation to ensure safety and maintain your warranty.
FAQ
What is the best propane tankless hot water heaters for beginners?
For beginners, the Rinnai RE140iP is an excellent choice. It offers a great balance of performance and user-friendliness from a highly reputable brand. Its 5.3 GPM is sufficient for most homes, and the LED screen with service reminders simplifies maintenance. It’s a reliable unit that removes much of the guesswork, making it a solid first step into the world of tankless heating.
How much should I spend on propane tankless hot water heaters?
You can expect to spend between $400 and $900 for a quality residential unit. Budget models can be found for under $300, while high-capacity, premium models with advanced features can exceed $1,500. It’s wise to invest in a mid-range model from a reputable brand, as this typically offers the best balance of performance, durability, and long-term value.
What features are most important in propane tankless hot water heaters?
The most important features are the flow rate (GPM), BTU output, and the required temperature rise for your climate. After that, look for a high-quality heat exchanger (copper is best), comprehensive safety features (like freeze and overheat protection), and a strong warranty. User-friendly features like a digital display are also highly beneficial for daily use and maintenance.
How do I maintain my propane tankless hot water heaters?
Maintenance is relatively simple but crucial. The most important task is to flush the unit annually (or more often in areas with hard water) to remove mineral scale buildup. This involves circulating a descaling solution, like vinegar, through the heater. You should also regularly inspect the air intake and exhaust vents for any blockages to ensure safe and efficient operation.
Are expensive propane tankless hot water heaters worth it?
For large families or homes with very high hot water demand, expensive models like the Rinnai RX199iN are absolutely worth it. Their higher GPM and BTU output ensure that multiple showers and appliances can run simultaneously without issue. They also often come with higher efficiency ratings and more advanced features, leading to greater long-term energy savings and convenience that justify the initial investment.
What brands make the best propane tankless hot water heaters?
Rinnai is widely considered a top-tier brand in the tankless water heater market, known for its reliability, performance, and excellent warranties. Other reputable brands include FOGATTI and MIZUDO, which offer great features and value. Brands like VELPAX and forimo provide solid, budget-friendly options that have gained popularity for their reliable performance at an accessible price.
How long do propane tankless hot water heaters typically last?
A well-maintained propane tankless water heater can last 20 years or even longer. This is nearly double the typical lifespan of a traditional tank water heater, which usually lasts about 10-12 years. The longevity is a major selling point and contributes to their excellent long-term value, as you’ll replace them far less frequently.
Can I find good propane tankless hot water heaters on a budget?
Yes, you can. Models from brands like forimo, VELPAX, and Nessxa offer excellent performance and safety features at a very competitive price point. While they may not have the massive output of premium units, they provide more than enough hot water for apartments, small homes, or budget-conscious families, making the switch to tankless technology accessible to more people.
Do I need professional installation for a propane tankless water heater?
Yes, professional installation is highly recommended and often required to keep the manufacturer’s warranty valid. Installing a gas appliance involves working with propane lines, venting, and electrical connections, which can be dangerous if done incorrectly. A licensed professional will ensure the unit is installed safely, efficiently, and up to local building codes.
What is the difference between condensing and non-condensing models?
The main difference is efficiency. Condensing tankless heaters have a second heat exchanger that captures extra heat from the exhaust gases, making them over 90% efficient. Non-condensing models are typically 80-85% efficient because this heat is lost through the vent. Condensing units cost more upfront but can provide greater energy savings over time, especially in cold climates.
Final Verdict
After extensive testing and comparison, we confidently recommend the Rinnai RE140iP Indoor Propane Heater as the best overall choice for most homeowners. It delivers the ideal balance of powerful performance (5.3 GPM), trusted Rinnai reliability, and smart, user-friendly features. Its strong warranty and energy-efficient design make it a wise long-term investment that will provide endless hot water for years to come.
For those on a tighter budget, the forimo 4.74 GPM Black Indoor Heater offers incredible value. It provides reliable performance and a wide temperature range without compromising on essential safety features, making it a fantastic entry-level option.
If you have a large household with high demand, the premium Rinnai RX199iN Smart Sense Heater is the ultimate solution. With its massive 11.1 GPM output and dual-fuel capability, it’s an unmatched powerhouse that guarantees you’ll never run out of hot water.
Your next step is to assess your home’s specific GPM and temperature rise needs using our buying guide. Once you have your requirements, you can confidently choose the model from our list that best fits your home and budget.
