5 Best Outdoor Tankless Gas Water Heaters

Have you ever been considering upgrading your water heater?

Then, outdoor no-tank gas-powered models deserve a solid mention.

But not sure which one to pick?

Well, the good news is, in this outdoor tankless gas water heater review, we’re going to show you five sought-after models from some of the most popular brands.

Read on to familiarize yourself with these five best outdoor tankless gas water heaters and get yourself the best of the best, which suits your needs.

Best Outdoor On Demand Gas Water Heater – Top Picks

The following chart will help you to compare our recommended five models to decide which model best suits your needs.

  • Best Propane Water Heater: Rinnai V53Dep RV53DeP, 5.3 GPM, V53DeP-Propane/5.3: This tankless water heater provides up to 5.3 GPM, uses propane as fuel, features ThernaCirc360 technology, has a maximum BTU output of 120,000 enough for a one-bedroom, can be drained during cold months, and has a user-friendly interface.
  • Best Whole House Water Heater: Camplux Pro Natural Gas 6.86 GPM: This model boasts a 6.86 GPM flow rate, 0.79 GPM startup water flow, a maximum of 180,000 BTU/h gas input rating, a maximum energy factor of 0.82, low NOx emission level, and heats up automatically if the temperatures get below 40 degrees F.
  • Best RV Water Heater: Thermomate ZERO16 4.23 GPM Propane Gas: A stylish outdoor water heater that starts with only 0.7 PSI of water pressure, boasts a 4.23 GPM flow rate, a stainless steel main burner that reduces gas consumption and burning noise, and comes with anti-freezing protection.
  • Best Natural Gas Water Heater: Noritz NR66ODNG 6.6 GPM: A tankless gas heater with an output of between 15,000 to 140,000 BTU/h,6.6 gallons GPM, saves energy by nearly 50%, emits low NOx hence environmentally friendly, boasts a compact footprint and a solid warranty.
  • Best Outdoor Water Heater: AQUAH Outdoor Liquid 2.7 GPM Propane: A 10L outdoor water heater that features a 2.7 GPM flow rate, provides 25-110 PSI of water pressure, 68,000 BTU heating capacity, boasts an electrical automatic pulse ignition, and is equipped with a digital readout for the output temperature.
best outdoor tankless gas water heater

Here Are the Best Outdoor Tankless Gas Water Heaters

The no-tank models are more efficient than traditional tank-type models. What’s more, with tankless models, you can avoid using water that has been stored in a storage tank with accumulated scale and rust.

But why gas models?

Gas water heaters heat water 50% faster than an electrical model. Moreover, they yield a higher flow rate and provide superb energy efficiency and utility savings.

But not all water heaters are created equal. A decent model will save you power and gas bills every month. So, finding the right one that will offer you the best value for your money is quite challenging.

We have researched for you and found the following five options. You’re certain to find the right one to meet your hot water needs

Check them out.

1. Rinnai V53DeP – Best Propane Tankless Water Heater

Rinnai V53DeP - Best Propane Tankless Water Heater

Rinnai is the #1 brand in North American for water heating products.

In the water heating product industry where tankless variations are getting complicated, Rinnai comes to the rescue. To relieve the technologically challenged people, this brand has made its mark to impress us.

If you’re in the search for such a gas water heater that will just get the job done simple and straightforward, check out the Rinnai V53DeP. It’ll undoubtedly make work faster, easier, and more efficient.

Rinnai V53DeP will never run out of hot water and leave you in the cold. This no-tank water heater provides up to 5.3 gallons of hot water every minute, depending on the ground temperature.

It is a high-performance model that uses propane as fuel. With maximum BTU output of 120,000, it provides plenty of hot water for a one-bathroom home in warm areas.

This model is also well-suited for a seasonal vacation cabin where the unit can be drained and shut down during cold months. Notably, a colder climate can reduce hot water flow.

This non-condensing water heater conserves energy without spending a lot. One of the unique features of this model is its ThernaCirc360 technology.  It allows you to recirculate the hot water faster and better.

V53DeP comes with a user-friendly interface for easy control and operation. This means that you do not need to suffer those unclear instruction manuals or those fancy controls.

You’ll also be amazed at its Control-R 2.0 mobile app feature. It lets you adjust the settings and remotely put the system into vacation mode.

What’s more, the Wi-Fi monitoring allows the Rinnai service provider to monitor and address the unit’s issues before you experience a break in service.

When it comes to installation, you can rest assured that it won’t be much hassle to set up. Plus, the compact design of this unit takes up very little space to fit in.

Finally, V53DeP offers a great residential factory warranty. It comes with a 10-year warranty on the heat exchanger and a 5-year on the part. You’ll also enjoy a 1-year labor warranty.

Overall, this propane tankless water heater wins out for lower costs, easier installation, and more efficiency.


  • Super easy and straightforward to use
  • Unsurpassed quality and innovation
  • High-efficiency ratings
  • Compact and space-saving design
  • SCAQMD approved
  • Certification: Energy Star, CSA, and AHRI


  • This model is not suitable for larger households with more than two bedrooms due to the medium flow rate.
  • Recommended to install outdoor only; can’t be mounted indoors.
  • The flow rate is steady only in warmer climates, but in colder areas, it may decrease.

2. Noritz NR66ODNG – Best Natural Gas Tankless Water Heater, Residential

Noritz NR66ODNG

Noritz has been a leader in the water heating product industry for more than six decades. It is a well-known brand for manufacturing energy-saving and superior quality water heaters that offer excellent value.  It comes up with an impressive lineup of wide-ranged water heaters.

For those who don’t know, we like to state that Noritx is a Japanese brand. It introduced the first electronically controlled and modern no-tank water heaters in the industry.

Noritz NR66ODNG water heater is an investment that pays for itself.

It is perfect for residential use. Its no-tank design provides an endless supply of hot water for apartments, townhouses, and condominiums with 1-2 showers.

Notably, this model’s gas input is between 15,000 to 140,000 BTU/h which is more than ideal for homes with two bedrooms.

NR66ODNG is specifically designed to be a low-cost and economical replacement for a tank-type water heater. It delivers an impressive flow rate of up to 6.6 gallons of hot water per minute.

This model saves an average of nearly 50% on monthly utility bills compared to tank-based water heaters. Thanks to its no-tank design and high-efficiency heat exchanger.

The uses of natural gas as fuel also add to its energy efficiency. The UEF factor of this model is around 0.81, which is excellent for regular uses.

Noritz NR66ODNG is for safe- environment. Because of its carbon reduction technology, this unit emits Low NOx that makes it environmentally friendly.

The compact footprint will save space without compromising power. It takes significantly less room than conventional water heaters. It is also easy to install.

Most importantly, like any Noritz tankless water heaters, this model is also equipped with exclusive safety features to prevent scalding water from reaching your faucet.

You can enjoy its reliable performance for up to 20 years. Noritz offers the best water heater warranty in the industry. This product includes a 12-year warranty on the heat exchanger, five years on parts, and one year of labor.


  • Direct ignition – No standby pilot light
  • Reliable and long-lasting
  • Compact and modern design
  • Easy to install and operate
  • Energy Star rated for reduced energy consumption
  • Relatively long warranty time


  • It takes a little longer to heat water properly.
  • Not a budget-friendly option

3. Camplux Pro WA686NGS – Best Whole House Gas Tankless Water Heater

Camplux Pro WA686NGS

WA686NGS is one of the largest outdoor models of the Camplux tankless water heater lineup.

Camplux WA686NGS comes with a high-capacity water flow that provides endless hot water for whole-house use. It ensures the instant hot water supply for 3 to 4 persons whole home shower and kitchen at the same time.

The 6.86 gallons per minute flow rate is more than enough for multiple simultaneous applications. It only takes a few minutes to deliver instant hot water at this flow rate. Notably, it has a 0.79 GPM startup water flow.

This model not only comes with a generous flowing rate but also incorporates several features to boot.

Firstly, with its maximum 180,000 BTU/h gas input rating, it saves you energy and money. It can save you up to 50% on water heating costs.

This natural gas model activates with a maximum energy factor of 0.82. Thanks to its innovative combustion technology that reduces gas combustion and burning noise.

Most importantly, it’ll help you to conserve the environment with its LOW NOx emission level (9.5 ppm) for protection.

This model’s constant temperature function helps you experience reliable and consistent hot water at a pre-set temperature.

Conveniently, with the included digital remote control with a 3.3 feet cable, you can easily control or adjust the water temperature.

WA686NGS ensures your safety with its advanced multiple protection features. This is an anti-freezing protection device. That means it heats automatically when the temperature is lower than 40-degree F. Thus it helps to avoid freezing in cold areas.

Other safety features include dry combustion protection, overheat protection, flame-failure protection. It also incorporates low water flow- and high water pressure protection.

With an outdoor installation, you won’t need any additional vent pipe. It comes with approved fittings and adapters for ease of installation. Moreover, the compact and wall-mounted design saves you valuable storage space for other applications.

Finally, you’ll appreciate its aesthetically pleasing and simple design. Moreover, the housing features a durable UV-coated cover for outdoor installation.


  • Well-made and durable
  • Designed for whole-house use (3-4 persons)
  • Impressive flow rate
  • Low NOx emission levels for environmental protection
  • Multiple protection features for safe use
  • Wind- and waterproof; anti-exposure
  • High thermal efficiency (88.5%)
  • Energy Star compliant
  • Simple and compact design for easy installation
  • Convenient and hassle-free operation
  • CSA certified for the USA and Canadian use


  • Not recommended to use for elevation above 2000 feet

4. Thermomate ZERO16 – Best RV Water Heater

Thermomate ZERO16 - Best RV Water Heater

Thermomate ZERO16 is one of the popular propane tankless water heaters for outdoor with a super low-pressure startup. It delivers continuous hot water wherever and whenever you need it.

This outdoor model is not only stylish but also compact and space-saving. It suits boats, campsite, RV’s and more. It is portable for outdoors to bring a fantastic hot shower for you to the beach or campsite.

Surprisingly, this unit starts up with only 0.7 PSI of water pressure. So, you don’t need to use the pressurizer pump anymore. Thanks to its exclusive dual solenoid valve with one magnetic water flow sensor that lets the heater work at low water pressure.

Conveniently, even at high pressure, it delivers stable water flow to meet the requirements of those in water shortage areas, especially in rural areas.

The energy-saving design of this model instantly provides endless hot water on demand and only as needed. The 4.23 GPM flow rater meets a variety of needs.

Moreover, its stainless steel main burner contributes to decrease gas consumption and burning noise. The burner is also corrosion-resistant with a long lifespan.

Thermomate ZERO16 includes top-notch safety features that make the product safe to use at any time. It comes with anti-freezing protection that enables it to use in cold temperatures.

The over-heating protection ensures the water doesn’t get extremely hot to burn your skin. The unit also automatically shuts off its gas supply in case unexpected flame out.

Of course, the simple dial knob design and digital display make it easy to operate.

Although ZERO16 is designed for outdoor use, you can install it indoors. For indoor, you have to install flue pipe or duct and well-ventilation.


  • Stylish and compact design
  • Energy-efficient and economical
  • Low-Pressure Startup
  • Multi-level safety protection
  • Light-weight and portable
  • Easy to install and maintain
  • Comes with extra parts for easier installation


  • Several users have mentioned that the produced water is very hot even on the lowest temp setting.

5. AQUAH JSD20-K Outdoor Liquid Propane Gas Tankless Water Heater


If you’re looking for an affordably-priced gas water heater for outdoor, JSD20-K is the best choice for you. Considering the built-quality, features, and performance, the price of this model is more than fair.

It is one of the highest-rated models among multiple AQUAH gas tankless water heaters.

Although AQUAH is not a well-known brand, their water heating product deserves a solid mention when it comes to energy efficiency and durability. Their water heating devices offer a well-balance between performance and price. The JSD20-K is no different.

This 10L outdoor water heater is intended for use in warm weather where the temperature is above the freezing point. You can enjoy endless hot water at 2.7 GPM with a temperature rise of 45-degree F.

It provides 25 to 110 PSI of water pressure and around 68,000 BTU of heating capacity. You’ll be surprised to know that this model maintains an 85% energy efficiency rating while in operation.

It is worth noting that the AQUAH’s patented enclosed loop heating system helps keep the unit operating at a lower energy cost.

This high-performing unit can deliver hot water in minutes. With an electrical automatic pulse ignition, it requires no standing pilot.

Moreover, no electric hookup is necessary as it is operated by 2 D batteries (not included) or 110V AC as an alternative. So, you’ll always have hot water even if there is no electricity.

Conveniently, there is a winter/ summer switch. It cuts off half of the fuel during hot weather. It also allows them back again when it gets cold, making it perfect for outdoor use.

This unit also comes equipped with a digital readout (degree C) of the water output temperature.

AQUAH is very serious about safety.  AQUAH JSD20-K comes with many safety features.

Some of the notable safety features of this model are:

  • flame adjustment for temperature setting
  • anti-dry combustion safety protection
  • over water pressure protection
  • auto cutoff protection in case of an accident
  • gas leak and overheating safety control

This water heater seems to work nicely for many years. In addition to this, JSD20-K comes with stainless steel rain cap for outdoor installation. It also features splash-proof and corrosion-proof liners.

AQUAH offers a 5-year limited warranty on the heat exchanger and a 1-year warranty on all other components.  While this isn’t the most impressive warranty, it is still good considering its asking price.


  • Simple installation
  • Designed to use hot weather
  • Cost-effective and reliable
  • Double-wall construction for extra durability
  • Quite affordable


  • Designed for use ONLY in warm climates where the temperature never falls below the freezing point.

Things to Consider When Buying an Outdoor Tankless Gas Water Heater

The following section will show you how to choose the right model for you and your needs!

Our buying guide covers everything you should know to make an informed purchase.

Flow rate

Before adding a model to your cart list, figure out your hot water usage. Then, buy the appropriately sized model that can adequately meet your needs.

You don’t need to calculate your hot water needs precisely, but you need to have a general idea of the flow rate (expressed in GPM).

We don’t recommend getting a unit with the highest GPM flow rate available. This is often more than the average household hot water needs. So, there is a possibility of wasting of some energy consumption.

What’s more, this biggest size unit will take up large space. It’ll also need a specific amount of clearance around it.

Water Pressure (PSI)

The water pressure of a gas-powered unit is referred to in pounds per square inch (PSI). This factor determines how rapidly hot water output travels through the plumbing and to the exit point from a water heater.

For optimal performance, make sure your selected model comes with enough PSI to accommodate your plumbing style and home size.

Low startup

If you plan to use this device in rural areas, RVs, camping, or boat, select a unit comes with a low water pressure startup. It’ll really help you for operating your water heater when the water pressure fluctuates every time someone else in the RVs, boat, or campground opens a faucet.

Heating Capacity (BTU)

Check the heating capacity of the model you plan to buy. Heating capacity is measured in British thermal units (BTU). It describes how much power the unit comes with to heat water. The higher the BTU rating, the higher the capacity of the unit to produce more and hotter water in a shorter time.

Low NOx

It is essential to note the gas on-demand water heater you’re considering buying is classified as Low NOx.

Notably, Low NOx refers to the burner that emits considerably less amount of certain types of chemicals ( such as nitrogen oxide and nitrogen dioxide). So, keep an eye on low NOx as a good feature for your selected model.

Overall Dimension

Although no-tank models are noteworthy for their compact and space-saving design, you should still carefully consider their size or dimensions. If you intend to install your new device in a compact space to facilitate safe and efficient maintenance, you have to provide an optimal amount of space around the unit.

In addition to the dimensions of the device, you should also leave a few extra inches on each side of the unit. It’ll provide space for safety venting and fuel source pipes.


The cost of tankless gas-powered water heaters varies based on several features.

Modern no-tank gas models also feature many different safety functions that make them a safe option in various settings but it adds up to its price.

Unfortunately, many buyers worry that these heaters are costly and require complicated and expensive installations.

The good news is that many of the no-tank units are simple to install and take up less space. So, you have more options for where you can install them than you might have with a traditional water heater.

Moreover, the energy savings of these gas water heaters alone may surprise you. A gas-powered no-tank model is much more efficient than the models with a storage tank.

These units also have a far longer life than a conventional water heater.


That’s it!

When you look at these five models featured above, you’ll notice several crucial benefits they offer that their competitors don’t.

But out of these best outdoor tankless gas water heaters, which one is your personal best buy?

Unfortunately, it can be hard to say for sure. It depends on your needs and budgets.

However, any of these gas-powered no-tank models can make a big difference in your comfort, energy-efficiency, and water heating bill.

Now it’s your turn.

Choose any of these models according to your need; you won’t be sorry!

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