page title icon 10 BEST OUTDOOR TANKLESS WATER HEATER 2021 | complete buying guide

If you are ready to install a water heater in your house and finding the best outdoor tankless water heater then you have entered the right place to get all of your answers. Keeping in view the requirement of the house, people can decide the best one for them. It is not necessary that the appliance that is best for one person also works the same for the other person.

Outdoor tankless water heaters are superior to conventional tank water heaters. They are more efficient water heaters and provide instant hot water. Also, they are more energy-efficient, using less energy, and providing more water. Looking more, the best feature of these tankless water heaters is their space-saving quality.

Outdoor tankless water heaters have all these features and also have some distinct features of venting and exhaust of steam or gases. People living in small houses usually have not sufficient space in their homes. They want to have a small outdoor tankless water heater that can be adjusted in a small space of garage or backyard.

Indoor tankless water heaters cause a major problem of venting. Venting pipes are required to install that not only increase the cost but also have a fear of leakage from pipes. Every appliance releases some gases that are not good for health. These gases are very dangerous and led to many health problems.

Outdoor tankless water heaters are very feasible to use in camps, RV, or any other outdoor recreational places. They can be easily and instantly installed anywhere. People can easily carry with them and get hot water whenever or wherever they want. Some people are very appearance-conscious. They don’t want the tankless water heater to affect the appearance of their house. Also, sometimes the casual grey or white color does not match with their interior paint or decoration. They want warm water for their body but not the tankless water heaters for settling inside their kitchens or homes. Also, they take more space.


To get rid of all the problems, people intend to move towards outdoor tankless water heaters. Our team has done a lot of research on the pros and cons of the best outdoor tankless water heaters. This research will surely help you to find the best one for you. Read it and get the best one for you.

Image Product Details   Price
backpac Rinnai V65EP 6.6 GPM Brand: Rinnai
47.4 Pounds
120 Volts
Check Price
backpac Ecosmart ECO 18 Brand: ECOSMART
Model: ECO 18
Weight: 14 Pounds
Voltage: 240 Volts
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backpac Camplux 5L 1.32 GPM Brand: Camplux
Model: AY132
Weight: 14.08 Pounds
Voltage: 3 Volts
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backpac iHeat Tankless S-16 Brand: iHeat Tankless
Model: S-16
Weight: 3.89 Pounds
Voltage: 240 Volts
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backpac Eccotemp L5 Brand: Eccotemp Systems, LLC
11.2 Pounds
3 Volts
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backpac GASLAND Outdoors Brand: GASLAND
15.71 Pounds
3 Volts
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backpac EcoSmart ECO 11 Brand: Ecosmart
ECO 11
6.5 Pounds
220 Volts
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backpac Rinnai Outdoor Brand: Rinnai
43.6 Pounds
220 Volts
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backpac Eemax EEM24013 Brand: Eemax Inc.
8.08 pounds
240 volts
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backpac Marey GA10LP Power 10L Brand: Marey
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1. Rinnai V65EP 6.6 GPM

Rinnai V65EP 6.6 GPM
  • Wi-Fi connection
  • Energy factor 0.82
  • Easy installation
  • More than standard amps are required
  • Users have to but temperature controller separately

As coffee is the demand of the winter season, warm water is the main essential for the body. To keep healthy in the winter season, people should have warm water showers. If we start looking for the best outdoor tankless water heaters then Rinnai models will be on the top. Rinnai is a very famous brand because of its modern tankless water heaters.

Rinnai V65EP is from the V series of Rinnai and has very attractive features. Starting with its flow rate, which is approximately equal to 6.6 GPM. This high flow rate is very high and sufficient to fulfill the hot water need of the whole house. This flow rate can be vary depending upon the inlet water temperature.

Due to the presence of ThermaCirc360 technology, users can easily control and maintain the desired temperature of the water. This outdoor tankless water heater can also be connected with Wi-Fi. Users have a Rinnai app on their phone. In case they are not using it or out of home, the user can easily put the heater on vacation mode. This saves energy and increases its efficiency. With all these advanced features, Rinnai also offers a warranty larger than any other brand. It gives users a 12-years warranty on heat exchanger, a 5-years warranty on parts, and also offer a year labor warranty. Although the user installs it outdoor, still it emits very few nitrogen oxides. Thus, it provides users a safe environment.

Key Features

  • ThermaCirc360 technology
  • Flow rate up to 6.6 GPM
  • 10300 to 15000 BTU output
  • Compact size 9 x 14 x 23 inches
  • High efficiency
  • 5-years parts warranty and 12-years heat exchanger warranty
  • 1-year labor warranty
  • Temperature range 98 degrees F to 140 degrees F

2. Ecosmart ECO 18

Ecosmart ECO 18
  • Affordable Price
  • Compact size 3.63 x 14 x 17 inches
  • 3/4 NPT water connections
  • Digital temperature control
  • Users complain about a warranty claim

Before buying any appliance, people usually refer to the brand name attached to the appliance rather than its features. The brand is preferred because it gives reliability to users. Ecosmart is a very well-known and trustable brand. ECO 18 is one of its best outdoor tankless water heaters. ECO 18 has a flow rate of up to 4.3 GPM. This is not so much high but enough to fulfill the water needs of a small house.

Components of ECO 18 are made up of stainless steel and rods are from copper. This makes the heater very durable. The researchers have approved its durability by applying high pressure on it. Having a very compact size and low weight, the user can easily install it at any small place outside their homes.

Insulated with advanced self-modulating technology, ECO 18 can automatically adjust its water temperature according to the inlet water pressure. Increasing the pressure decrease the temperature of the water. It provides a lifetime warranty for residential use. A lifetime warranty with advanced features causes users to attract toward it.

This has a LED in the front panel displaying the current temperature of the water. The temperature can easily be adjusted through a knob. The temperature range that ECO 18 can provide is between 80 degrees F to 140 degrees F.

Key Features

  • Flow Rate Up to 4.3 GPM
  • Advanced self-modulating technology
  • Lifetime warranty
  • High efficiency
  • Saves 60 % of heating cost
  • Stainless steel component and copper rods
  • Temperature range of 80 degrees F to 140 degrees F

3. Camplux 5L 1.32 GPM

Camplux 5L 1.32 GPM
  • Stainless steel burner
  • Copper tinning heat exchanger
  • Compact size
  • Temperature control setup
  • Low operating pressure
  • CS regulator
  • Low flow rate
  • Frequently battery charging

When we talk about the best outdoor tankless water heaters, some people may consider it as a heater that can be just installed outside their houses. Significantly, it is not true. The outdoor installation also means that it can be easily useable in camps or any other recreational tour.

Camplux 5L has a flow rate of 1.32 GPM. This flow rate is enough for 1 shower usage only. Camplux 5L is mainly used for a person living alone. Living alone led to many expenses. It is very suitable as it is very budget-friendly.

Talking about its internal and external structure, its burner is made up of stainless steel and the heat exchanger is from tinning copper. These high-quality materials make it is a very durable appliance. Having a folding handle makes it very convenient for outdoor set-up. It offers a temperature range of 46.4 degrees F to 114.8 degrees F.

We can define the best appliance as a device that meets the standard of safety. Camplux 5L provides overheating protection as well as anti-freezing protection. Even it starts up at a very low water pressure of 3 PSI, it also provides low or high water flow protection. It can also be powered by 2 ‘D’ batteries, so can be used in the areas where there is frequent power break down.

Key Features

  • Flow Rate up to 1.32 GPM
  • Anti-freezing protection
  • Overheating protection
  • 2 ‘D’ battery ignition system
  • Temperature range of 46.4 to 114.8 degrees F
  • 28000 BTU power output

4. iHeat Tankless S-16

iHeat Tankless S-16
  • Compact size 3.5 x 7.7 x 11.5 inches
  • Low weight
  • Saves 60 % of heating cost
  • Easy installation
  • Takes time to maintain the desired temperature

The tankless water heaters used at home are not always suitable to use outdoor. But some tankless water heaters are also suitable for camping or another outdoor place. But when we talk especially about yachts, boats, or other places near the ocean, people fear to use these tankless water heaters. As most of the heaters are electricity-based and using it near watery places is dangerous.

iHeat tankless outdoor water heater is waterproof. It is enclosed by stainless steel which is a good insulator. iHeat S-16 like other S series members is preferable to use in sterile places like hospitals, kitchens, schools, and child care centers. It provides a flow rate up to 3.5 GPM which is roughly approximated as 2 showers and 1 sink usage.

It has a very small and compact size. Smaller dimensions make it easy to be easily fitted in any cabinet or small place. A waterproof touchpad is fabricated in the front of this outdoor tankless water heater. People can easily adjust the temperature by using this touchpad. It offers a 1-year warranty on elements, three years warranty on components, and five years warranty on leaks.

Key features

  • Flow rate up to 3.5 GPM
  • Waterproof body
  • Stainless steel enclosure
  • Touchpad for temperature control
  • 1-year warranty on elements and 3-years warranty on components

5. Eccotemp L5

Eccotemp L5
  • Small size
  • Affordable price
  • Electronic batteries ignition
  • Thin heating coils

Hot showers are very necessary not only for humans but also for their pets. Eccotemp L5 tankless water heater is one of the best outdoor tankless water heaters. A very few people buy it for indoor purposes. Most of the people buy it to use in garages or for their pet houses. Other people purchase this wonderful heater for camping, family tours, and also in RV.

Ecctemp L5 has a flow rate of 1.5 GPM enough for outdoor usage. It weighs just 20 has a handle that makes it very easier to carry this small weight anywhere. Usually, heaters require very high activation pressure but eccotemp L5 just needs 20 PSI for its has two knobs in front of the heater. One knob is used to control the temperature of the water and the other for gas. These knobs help the user to achieve the desired temperature in a range between 50 degrees F to 140 degrees F.

The installation process for this tankless heater is very easy. It has three outlets at the bottom of the heater. At the very first outlet, connect the gas input. In the other two outlets, connect one with the input water hose and the second with the output water. This installation does not require any plumber. User can easily install it anywhere he wants. Electronic ignition is done by 2 ‘D’ batteries. If it runs more than 20 minutes continuously, it automatically shut off for a few minutes.

Key Features

  • 1.5 GPM Flow Rate
  • Shut-off safety
  • Temperature range of 50 degrees F to 140 degrees F
  • 20 PSI activation pressure
  • Temperature control knobs
  • CSA certified

6. GASLAND Outdoors

GASLAND Outdoors
  • Highly portable
  • Saves 11.5 % of energy
  • Automatic shut off at a high temperature
  • 2.5 PSI activation pressure
  • Efficiency decreases above 33000 feet

If you are looking for a multipurpose tankless water heater then GASLAND 6L is the perfect choice for you. It has a flow rate of 1.58 GPM. Manufacturers design it by keeping in mind the needs of an RV or a camp. But it can be used inside small houses.

It meets all the safety standards of Canada and the US. It provides anti-flaming protection as well as anti-freezing protection. Residual water can be discharged through an anti-freezing drain. Usually, some heaters overheat over long time usage. It provides overheating protections also thus provides safety to the users. In case when the temperature rises above 167 degrees F, it provides overheating protection by automatically shut off the heater.

It supplies endless hot water as soon as the users open the faucet. Users get instant hot water at just 2.5 PSI water pressure. Having three knobs in front of the heater helps users to control the temperature of the water as per their requirement. A Small LED just below the center knob is present for the current water temperature display. It gives a maximum output power of 41000 BTU.

Advanced combustion technology is installed in this tankless water heater. This technology helps the heater to burn more noise and less gas. Also, it uses energy only when someone is using warm water. It has a very small weight. People can easily carry it with themselves. It is mainly designed for outdoor installation but with the help of duct pipe or vent, users can also install this heater inside their homes.

Key features

  • Flow rate up to 1.58 GPM
  • CSA approved
  • Advanced combustion technology
  • 41000 BTU power output
  • Anti-freezing protection
  • High water temperature safety

7. EcoSmart ECO 11

EcoSmart ECO 11
  • Compact size of 3.75 x 8 x 11.5 inches
  • Affordable price
  • Energy factor 0.98
  • Sleek and compact design
  • Need to install by a licensed electrician
  • Does not provide hot water at low pressure

EcoSmart is a high rated brand popular all over the world due to its incredible appliances. Tankless water heaters of EcoSmart also fulfill the standard criteria and are considered as one of the best tankless water heaters. Specifically, talking about outdoor tankless water heaters, ECO 11 is considered as the best one.

Comparing its size with traditional tank water heaters put buyers in a shock as it is 90 % smaller than the conventional tank water heaters. It takes a very small place in the user’s house. If they are using it for outdoor purposes then it is also the best choice. Having a flow rate of 2 GPM, Users can easily use it for 1 shower and 1 sink usage.

Eco 11 is patented with self-modulating technology. This technology will let the heater to sense the water pressure. The heater can automatically adjust its temperature by inlet water pressure. It immediately heats water as soon as the user opens the faucet. Saving 60 % of electricity bills makes it very energy efficient. It has a high efficiency of 99.8 %. When we talk about its warranty, it gives an amazingly lifetime warranty on exchanger and other heating parts.

ECO 11 is suitable to use in areas where the inlet water temperature is 67 degrees F or above this. Providing the temperature range of 40 degrees F to 140 degrees F helps users to get instant hot water. Temperature can be increased or decreased by 1 degree by adjusting through knobs.

Key features

  • Flow rate up to 2 GPM
  • High efficiency of up to 99.8 %
  • Lifetime warranty
  • Advanced self-modulating technology
  • Temperature range of 40 degrees F to 140 degrees FDigital temperature display

8. Rinnai Outdoor

Rinnai Outdoor
  • Wi-Fi connection
  • Parts are easily replaceable
  • Energy-efficient appliance
  • Professional installation is required

Companies design different types of tankless water heaters. These heaters are suitable to be used in different situations. Some tankless water heaters are good to install inside the houses while others are designed to install outdoor. Some tankless water heaters are enough to fulfill the needs of a single person while others can fulfill the hot water need of the whole house. Also, tankless water heaters can vary depending upon the type of fuel needed for ignition.

When we specially talk about outdoor tankless water heaters, Rinnai stands first with its innovative models. Rinnai RL75eP has a flow rate of 7.5 GPM. This is a very high flow rate enough to provide hot water to 5 fixtures of the shower simultaneously. This outdoor tankless water heater also falls in the category of whole house tankless water heater. It is installed outside your house and saves space inside the home.

Penetrated with CircLogic technology, Rinnai RL75eP can perform recirculation technology automatically. This feature saves the time of the user as the user does not have to wait for hot water. This heater is also capable of a Wi-Fi connection. Users can easily adjust the temperature of water through the Rinnai app installed on their mobile phones. They can also put the heater on vacation mode when they are not at home. Rinnai provides a 12-years warranty on its heat exchanger, five years warranty on parts, and a year labor warranty also.

Key features

  • Flow rate up to 7.5 GPM
  • Circ Logic technology
  • Energy star verified
  • Energy factor up to 0.82
  • Less emission of carbon dioxide
  • 12-years heat exchanger warranty and 5-years parts warranty
  • 1-year labor warranty

9. Eemax EEM24013

Eemax EEM24013
  • No batteries required
  • Stainless steel components
  • Affordable price
  • Very reliable appliance
  • Sometimes it supplies Lukewarm water

Eemax EEM24013 is the best electric tankless water heater that can be installed outside the house. It provides a continuous supply of endless hot water. This outdoor tankless water heater can be used almost anywhere. It provides hot water of 2.4 GPM. This flow rate is not so high but sufficient for a small house.

It performs the heating of water only when the user opens the faucet. This on-demand working technology helps the user to get instant hot water without wasting extra energy. The most advanced self-modulating technology is fabricated in it. This technology allows the heater to adjust the temperature of water by inlet water pressure. More pressure means that less temperature is required.

It has a very small size easily adjusted anywhere in the house. Eemax EEM24013 has a very attractive design with a blue panel in front. If users want to install it inside their homes, they can do it. It has a very small size so can be easily fitted inside a cabinet and below the sink. Discussing its warranty, Eemax offers five years warranty on leaks and a year warranty on its parts.

Key features

  • Flow rate up to 2.4 GPM
  • Modern self-modulating technology
  • Very attractive design
  • Digital temperature display
  • Five-year warranty on leaks
  • One year warranty on parts

10. Marey GA10LP Power 10L

Marey GA10LP Power 10L
  • 5 years warranty
  • Temperature and water control knobs
  • Aesthetic and sleek design
  • High rated appliance
  • It provides extreme temperature conditions

Marey is famous due to its creative products for indoor as well as outdoor uses. They designed many tankless heaters each with an innovative design. Outdoor tankless water heaters are usually expensive than tankless water heaters. But when we look into the price of this Marey GA10LP, it is comparatively very low and budget-friendly.

Marey GA10LP offers a flow rate of up to 3.1 GPM. It can be easily installed at any place. It provides hot water only when users want to use hot water. A hot water shower is on the top of the list of essentials of winter. Due to instant working, it saves almost 60 % of electricity bills.

In some areas, there are frequent power outages. It is usually not an efficient thing to use electric heaters in such places. Marey GA10LP does not require any electrical connection or ignition. Thus, it is the best choice to use in such areas. By reading the manual provided by the company, the user can install this on their own. It provides very high energy efficiency of up to 97 %.

Key features

  • Flow rate up to 3.1 GPM
  • 2 ‘D’ batteries ignition
  • 97 % energy efficiency
  • No electrical connections are required
  • Easy and convenient installation

Rinnai Outdoor

Ultimate Buyer’s Guide to Buy Best Outdoor Tankless Water Heater

Before buying any appliance, the buyer should keep in mind some of the important features in his/her mind. Buying an appliance according to your requirement is the best thing you can do for yourself. Sometimes, an appliance has many attractive features and people buy it. When they start using that appliance, those appealing features are of no use.

Flow rate

Flow rate is measured in gallons per minute (GPM). This is one of the most important features of any type of tankless water heater. People using it for outdoor purposes usually do not require a high flow rate. A high flow rate is required when people want to use the tankless water heater for the whole house.

Weather conditions

When we talk about indoor tankless water heaters, the weather conditions do not affect the efficiency of the heater. But when the heater is installed outdoor, weather conditions like stormy winds, rain, etc. Try to buy an outdoor tankless heater that is resistant to such weather conditions.


Do many people think that what is the need for a warranty if we are buying a very good appliance? Purchasing a well-featured appliance is a good thing but sometimes parts stop working or other technical errors may occur. Always buy a product with a sufficient warranty. Many famous companies offer a warranty for many years. Some can even provide the product with a lifetime warranty.


“Set your standard according to your budget”. If buyers keep this in their mind, they would surely buy a good appliance within their budget. Propane tankless water heaters are more budget-friendly than electric tankless water heaters.

Input power source

Tankless water heaters vary depending upon the power input source. In some places, natural gas is not available. Buying a tankless water heater operating with natural gas is not the right choice then. On the other condition, electrical tankless water heaters are not suitable to use in places where there are frequent power outages. Propane tankless water heaters are easily available.

Size Which size is best to fulfill the need of your whole house? If you are using it at camps in RV, select a suitable size that fulfills your whole water requirements. Also, keep in mind the space available in your house.


Is it necessary to protect outdoor tankless water heaters?

Usually, some tankless water heaters are designed in such a way that they do not need any protection. They are usually resistant to extreme weather conditions. But some outdoor water heaters need to be covered in stormy weather.

Can outdoor tankless water heaters be used as a whole home water heater?

An outdoor water heater with a high flow rate can be used for the whole house. Heaters with low flow rate can be used for small houses as it does not provide sufficient water for a larger house.

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