The Best Propane Tankless Water Heaters

Energy-efficient and environmentally friendly propane tankless water heaters produce nearly immediate hot water with minimal waste. Right here, you can find the perfect model for your house.


Hot water is a basic necessity, but the variety of available tank-based and tankless systems may make selecting the correct water heater difficult. While traditional water heater tanks remain popular, contemporary tankless ones may provide several advantages. Installation expenses are low, and the machines are extremely energy efficient, so you’ll save money upfront and over time. Furthermore, a tankless variant may frequently be used where a tank could be more practical. There are also RV and camping variants available.

A tankless water heater delivers hot water “on-demand,” meaning it heats the water you need when needed. This way, there’s no fear of the tank running empty and no energy wasted, keeping water heated all day and night. Gas-fired models are extremely efficient. For individuals living in places where natural gas isn’t accessible, propane offers a versatile and economical option. Use this guide to understand what to look for when looking for the best propane tankless water heater and discover why the models covered here are considered among the finest propane tankless water heaters on the market.

How We Selected the Top Propane Tankless Water Heaters

When selecting our best recommendations for propane tankless water heaters, we extensively researched the industry to evaluate the various features and options available. We made certain to offer both high-output units for bigger families who want near-constant hot water and more compact units for smaller homes that may still enjoy hot water but at a lower cost.

Our investigation also led us to portable water heaters, which are great for campers and RV enthusiasts. We made certain to give a few alternatives, from enormous powerful units to compact lightweight versions across this broad spectrum. While most of the conventional indoor units in our top recommendations would almost certainly require expert installation, the dependability of their manufacturers should see them survive for years.

Top Choices

The sections above summarise the elements and features to consider while looking for the best propane tankless water heater. Examine these top options from well-known brands to find the model most suited to your requirements.

Rheem 9.5 GPM Propane Indoor Tankless Water Heater

This Rheem tankless water heater is great for efficiency, dependability, adaptability, and outstanding features. It’s a tiny indoor device rated at 9.5 GPM and a maximum of 199,000 BTU. It is enough to operate four showers (or similar) simultaneously. It has a DOE Energy Star rating of up to 0.93 and a market-leading UEF of up to 0.93. A water-saving feature can save up to 1,100 gallons of water each year.

Setting the preferred temperature is straightforward, thanks to precise digital controls. When maintenance is necessary, built-in sensors notify you. Compatibility with PVC venting pipe saves installation costs, and a venting distance of up to 150 feet gives you much flexibility regarding where you may put it.

Product Specifications

  • Type: Inside
  • 9.5 GPM is the flow rate.
  • Output Power: 199,900 BTU/h


Compact wall-mount design with a venting distance of up to 150 feet

Rated at a dependable 9.5 GPM, it is ideal for homes with 3-5 people.

Reduces cold water bursts and may help reduce water use by up to 1,100 gallons annually.


It is impressive capabilities, and compact form come at a premium cost.

Amazon sells the Rheem water heater.

Rinnai Winner
Rinnai 7.5 GPM Propane Interior Tankless Water Heater

With a flow rate of 7.5 GPM, this Rinnai indoor propane tankless water heater is easy to overlook. Despite this, it is a cost-effective alternative to high-output systems. With a maximum output of 180,000 BTU, it can operate two or three showers in succession, even in areas with colder groundwater temperatures. The unit has a UEF of 0.81.

The hot-water delay is reduced thanks to recirculation technology. Temperature control is accurate with digital control and Wi-Fi compatibility. While malfunctions are uncommon, this model will offer detailed diagnostic error codes if they occur.

The device can be equipped with conventional or concentric venting; horizontal venting is offered at an additional cost. Isolation and pressure-relief valves are incorporated, making yearly maintenance flushing considerably easier.

Product Specifications

  • Type: Inside
  • 7.5 GPM is the flow rate.
  • Output power: 180,000 BTU/h


  • The control panel is simple to operate and allows for precise temperature control.
  • The compact design saves space, and recirculation technology decreases hot-water delay.
  • It is Wi-Fi-capable and delivers specific diagnostic fault codes.


  • A professional installation is required.
  • This item is costly with its sophisticated features and numerous venting choices.

Amazon has the Rinnai water heater.

Rheem 7.0 GPM Propane Indoor Tankless Water Heater

Those seeking a low-cost indoor propane tankless water heater can choose this Rheem. With a UEF of 0.82 and a maximum output of 7.0 GPM and 160,000 BTU, this type can meet the demands of a 1- or 2-bathroom home.

Despite the low price, numerous outstanding features are offered. A digital thermostat provides precise temperature control and may be placed independently of the unit for increased convenience. A hot start program decreases water temperature changes caused by stop-and-start operations. While this type does need stainless steel venting, which raises the price, it remains an economical and energy-efficient solution for small homes or guesthouses.

Product Specifications

  • Type: Inside
  • 7 GPM Flow Rate
  • Output Power: 160,000 BTU


  • Up to two bathrooms are available.
  • Included are a remote control and a digital thermostat.
  • The hot start function helps to keep temperature swings to a minimum.


Steel venting is required, which raises the otherwise modest cost.

Amazon has the Rheem water heater.

Rinnai V65iP
Rinnai V65iP Propane Tankless Hot Water Heater

The indoor Rennai V65 is intended for smaller dwellings and has a rating of 6.3 GPM and 150,000 BTU. Nonetheless, UEF is high at 0.92, indicating that it delivers exceptional energy efficiency.

While the Rennai V65 lacks Wi-Fi and the software found on some of its more capable siblings, it does include a clear digital readout for precise control. The manufacturer promotes the model’s ease of installation but suggests hiring a professional.

Product Specifications

  • Type: Inside
  • 6.5 GPM is the flow rate.
  • Output Power: 150,000 BTU


  • A low-cost choice with a clear digital readout for precise control.
  • Provides continuous hot water for houses with up to 2.5 bathrooms.
  • The manufacturer promotes the model’s simple installation technique.


  • There is no recirculation technology.
  • Overall, the flow rate and power output are lower when compared to comparably priced versions.

Amazon has the Rinnai water heater.

Rinnai V65iP
Rheem Performance Platinum 11 GPM Water Heater

Rheem manufactures a variety of high-quality propane tankless water heaters, with the indoor Performance Platinum topping the line. It has a UEF of 0.93 and can produce up to 11 GPM and 199,000 BTU. It is intended to meet the demands of a four-bedroom house.

Recycling technology speeds up hot water transfer from the unit to the faucet or shower. The UL and CSA-certified system may be customized to meet homeowner consumption patterns, includes a digital screen for precise control, and can detect gas or water leaks. The unit’s compatibility with PVC venting minimizes installation costs and may save thousands of gallons of wastewater each year.

Product Specifications

  • Type: Inside
  • 11 GPM is the flow rate.
  • Output Power: 199,000 BTU


  • The high flow rate is ideal for up to four bathrooms.
  • Sleek contemporary design and a compact, practical size


  • Energy Star-certified and compatible with PVC venting to save money on installation
  • Combining design, features, and energy efficiency increases the price tag.

Amazon has the Rheem water heater.

Eccotemp 45H-LP 6 Outdoor Installation
Eccotemp L5 1.5 GPM Outdoor Tankless Water Heater

The Eccotemp L5 is intended for folks who enjoy being outside but dislike taking cold showers. It has a UEF of 0.8 and generates 1.5 GPM at up to 37,500 BTU. It only weighs 11 pounds, making it convenient to transport anywhere.

While the statistics are small compared to indoor versions, the Eccotemp L5 may create hot water up to 140 degrees Fahrenheit, depending on the conditions. All that is required is a low-pressure supply from a regular garden hose (but a 12-volt pump would boost performance). There’s no need to be concerned about power because two D-cell batteries power the ignition.

Product Specifications

  • Outdoor portable type
  • 1.5 GPM is the flow rate.
  • 37,500 watts of power


  • The small size makes it convenient for providing hot water on the move.
  • It is lightweight and has a carry handle, making it easy to transport.
  • 2 D-cell batteries provide convenient power.


  • Some concerns with temperature changes

Amazon has the Eccotemp water heater.

Camplux Tankless Water Heater
Camplux Pro 2.64 GPM Tankless Propane Water Heater

The Camplux Pro portable outdoor water warmer has outstanding specs. It only weighs 18 pounds yet can deliver up to 2.64 GPM and 68,000 BTU. It works with water pressure ranging from 3 to 110 psi (household water is typically between 45 and 70 psi), making it excellent for distant sites with low pressure. Two D-cell batteries power the ignition. A showerhead and a handy mounting bracket for your RV’s side are provided. It is a highly safe item that will switch off automatically if the water pressure exceeds the normal range or the flame fails. There is a drain plug for the remaining water to avoid freezing damage.

Product Specifications

  • Outdoor type
  • 2.64 GPM is the flow rate.
  • 68,000 BTU of power output


  • At only 18 pounds, this device is rather light.
  • It continues to function even when water pressure is minimal, like in distant regions.


  • Automatic safety shutdown avoids overheating or running if the flame fails.
  • Some hose adapters may not fit; further purchases may be required.

Amazon has the Camplux water heater.

What to Look for in the Best Propane Tankless Water Heater

Propane tankless water heaters provide hot water in a variety of settings. These adaptable devices may power a full house or provide a cost-effective option for a guest house. Some models can be attached to a tree when camping. It is essential to grasp the technical elements outlined below before deciding.

Indoor Versus. Outdoor

Indoor and outdoor propane tankless water heaters are offered. Indoor variants are tiny enough to fit considerably smaller locations than a standard water tank. Still, the gas supply must be obtained from outside, where it is nearly always kept. Furthermore, burning propane emits carbon dioxide (CO2), which is harmful in confined settings. Thus, venting is required. In most circumstances, this entails drilling a hole in an exterior wall or roof.

An outdoor variant might be considerably easier to install. It requires a cold-water supply and, of course, gas, but the only pipe needed to enter the home is the one that distributes hot water. While some require an electrical connection, portable variants often operate on batteries.

However, outdoor units have limits. A propane tankless water heater will function properly at temperatures below zero but must be protected from rain, snow, and severe winds. Similarly, models built for camping or other off-grid applications should be kept in inclement weather.

(GPM) Flow Rate

The flow rate of a tankless water heater refers to how much hot water the device produces, and it’s possibly an essential consideration in determining the ideal model for your needs. It is normally measured in gallons per minute (GPM), while certain European versions are measured in litres per minute (l/min), and one gallon equals 3.78 litres.

The GPM rating of a propane tankless water heater indicates how much hot water the device can provide. Broad assumptions can be made because the temperature of the water going in affects the accuracy. A normal faucet, for example, requires about 1 GPM of supply, but a shower requires 2 to 3 GPM.

When added together, everything in a house that consumes hot water simultaneously theoretically produces the GPM required for the family. However, the faucets, showers, tubs, and washing machines are unlikely to be utilized simultaneously. In practice, a unit of 5 GPM is generally sufficed for a modest home; 7 to 10 GPM would be enough sodium for a big residence. Those needing more capacity should look at twin and multiple heater systems.

Notably, the colder the mains supply, the harder the heater must work, resulting in a decline in GPM. The flow rate differential between a heater installed in the northern United States and a warmer southern state can be several GPM. Manufacturers typically give comparative numbers to assist buyers in making purchasing decisions.

BTU (British Thermal Units)

Heating power is measured in British Thermal Units (BTUs). It is the energy required to heat one pound of water by one degree Fahrenheit. In practice, the BTU rating is supplied per hour to illustrate how much heat a tankless water heater can deliver constantly. This is critical to consider because, without enough heat, the water travelling through the system may not be sufficiently heated.

There are mathematical techniques for calculating BTU requirements, but manufacturers typically offer precise recommendations. Some websites provide online calculators. It’s also worth looking at minimal BTU statistics, which indicate that the heater can run efficiently at low demand and doesn’t waste fuel. A 9 or 10 GPM propane tankless water heater may offer anywhere from 25,000 to 200,000 BTUs of heat, which many consider enough for a three-bathroom home.

Rating of Efficiency

A high-efficiency water heater saves money by efficiently converting fuel to heat energy. Some of the greatest propane tankless water heaters have stated efficiency ratings of 99 per cent, which is the best; 100% efficiency is unattainable because some energy is always wasted.

However, manufacturers have historically utilized several methods to gauge efficiency, which has caused misunderstanding. The United States Department of Energy (DOE) created an independent measuring standard known as the Uniform Energy Factor (UEF) in 2017. This enables prospective purchasers to make realistic comparisons. Figures are expressed as a fraction of one. These vary from a low of 0.8 to a high of 0.93 among the Top Picks in this guide.

Noncondensing vs condensing

Steam, or hot-water vapour, is an inevitable consequence of the heating process. Steam generally condenses into water droplets when it reaches a colder part of the heater. Two issues arise as a result of this. The first is the heat loss caused by steam escaping. The second issue is that the water ultimately begins to rust.

Noncondensing models exhaust the steam into the atmosphere. Moisture may reach temperatures up to 300 degrees Fahrenheit, so proceed cautiously. The procedure also consumes a significant amount of energy. Condensing models recycle the steam, capturing the energy and using it to heat the water. Though eventually vented to reduce corrosion, the temperature will have decreased to around 100 degrees Fahrenheit by the time this occurs. In other words, a condensing propane tankless water heater may use heat that would otherwise be squandered.

The disadvantage is that condensing models are significantly more costly. With heater lifespans ranging from 10 to 20 years, there’s plenty of time to make up the difference.


Venting is required for two reasons: to bring in fresh air for combustion and expel hazardous carbon dioxide afterwards. Separate ducts are usual, although some heaters employ a concentric vent—essentially, one pipe inside another. Although concentric forms are more costly, low-cost PVC is frequently utilized. Stainless steel is another alternative, although it is also more expensive. Venting is often done from the top of the device. However, side-venting types are also available.

It is critical to evaluate the venting needs of each model under consideration. It will affect installation, and certain models may require special ventilation equipment, which is typically not included in the purchase price.

Sizes and Weight

Propane tankless water heaters are typically wall-mounted and less than 15 inches deep. Compared to standard floor-standing boilers, this allows them to conserve much room. Nonetheless, physical measurements should be checked before planning the installation. Portable versions are significantly smaller. Weight will be an issue, although most are lighter than the 20-pound gas tank that powers them.

Additional Benefits

Some propane tankless water heaters include only simple dials for water flow and temperature and an LED to show whether the heater is on or off. However, there are a few more sophisticated features available:

  • Summer and winter settings take into account the ambient temperature. These are especially useful on outdoor versions and can significantly save fuel.
  • Digital screens allow more exact control by providing precise water temperature measurements. Heaters that are Wi-Fi-enabled can even be operated via an app.
  • Many portable versions feature the appropriate gas regulator to accommodate a normal 20-pound propane bottle; some even include a showerhead.

Devices that have been UL or CSA certified have been independently evaluated and meet various international safety requirements.

Setup and maintenance

Whichever propane tankless water heater is chosen, the installation will need various skills and instruments, including plumbing and modest building work. Buying them might be expensive if you want to conduct DIY installation but still need the tools. Furthermore, some manufacturers highly advise that a certified professional perform the installation.

Various criteria must be followed if a permanent propane tank is to be included in the installation. Although experienced DIY enthusiasts may be able to do the work themselves, hiring a contractor may be a superior option in many circumstances.

  • These are extremely durable equipment, but even the greatest propane tankless water heater will benefit from routine maintenance.
  • Those who live in hard-water locations might consider installing a cold-water filter to prevent calcium accumulation.
  • A yearly flush with a circulating pump and white vinegar delivers excellent demineralization, eliminating chemical accumulation that impedes function.

It’s a good idea to inspect fittings for signs of corrosion and replace any that need it during the yearly flush.


Even after reading this primer on propane tankless water heaters, you may want to learn more about the technical elements of this equipment. Some of the most commonly asked questions are answered here.

Q. What is the operation of a tankless water heater?

When you turn on the hot-water faucet, a flow sensor is triggered, which activates the propane burners, which heat water “on demand.” In a large tank, no water sits around, becoming chilly. When the water flow ends, the burners turn off, ensuring that no energy is lost.

Q. How large is the propane tank required for a tankless water heater?

The heater’s requirements determine it. Those designed for camping and tiny dwellings may be able to operate for several weeks on a typical 20-pound bottle. Larger propane canisters are available for larger-capacity heaters, or a permanent tank may be required.

Q. Can a tankless water heater heat the entire house?

Absolutely. There are models available to give hot water to households of different sizes. As noted in the previous question, the propane tank configuration should also be considered.

Q. How do you flush a tankless condensing gas water heater?

To execute this annual maintenance job, the propane and water sources must be turned off, and the electrical or battery must be unplugged. Typically, white vinegar is used to flush the system and eliminate debris. Manufacturers frequently give detailed instructions, but paying a professional to handle the work once a year should be relatively inexpensive if you’re hesitant.

Q. How do you monitor the gas pressure in a tankless water heater?

In general, there shouldn’t be any necessity. A regulator attached to the propane tank regulates gas pressure in these devices, and the right kind should have been installed during installation. A lack of hot water is frequently caused by a nearly empty propane tank or excessive water pressure. If you need to monitor gas pressure, a specialized manometer is required. In such a scenario, you should have your tankless water heater inspected by a plumbing specialist.