3 Best Outdoor Electric Tankless Water Heater Reviews & Experts Guidance

The electric tankless water heater is mainly powered by electric, no pipeline and venting kits are needed, therefore, the installation position of it is quite flexible. Most of the electric tankless water heaters can also be installed outdoor. But you need to make sure that some protection needs to be added for outdoor electric tankless water heater, or the severe weather may shorten the using life of it.

In this article, we would like to give you detailed reviews for best outdoor electric tankless water heaters, in order to help you choose the most suitable one based on your situations.

The 3 Best Outdoor Electric Tankless Water Heaters in 2019

Best Outdoor Electric Tankless Water Heaters Reviews

1. Stiebel Eltron Tempra 20 Plus Electric Tankless Water Heater

Stiebel Eltron Tempra series of electric tankless water heater is an improvement version, compared with original Eltron types, this series has digital temperature display and is able to keep the water temperature constant with the Advanced Flow Control. All other series including Tempra 12 Plus, 15 Plus, 20 Plus, 24 Plus, 29 Plus and 36 Plus are all in excellent working performance, they differ in required voltage only.

best outdoor electric tankless water heater
outdoor electric tankless water heater




  • Low working noise

Do you still feel it annoying in loud heating noise in your bathroom or kitchen? This unit is proved to be extremely quiet, you can hear no working noise in the process at all. And stylish compact size occupies little space on your outdoor wall.

  • Endless hot water

For the tank water heater, if you use hot water for a long time, the heated hot water will run out soon. But the instant outdoor electric heater is different, you can never run out of the hot water and it heats water fast.

  • Advanced Flow Control

The advanced flow control technology is able to smartly and automatically maintain the water temperature, enabling to give steady hot water for you in bathing or washing.


  1. Save at least 15-20% on the electric bill
  2. Support full power modulation
  3. Auto modulation technology
  4. Has the power to provide about 5 gallons water per minute, high flow rate machine
  5. High-level electronic parts and a reliable cover
  6. Able to support one or two bathrooms and kitchen faucet the same time
  7. The most technologically advanced electric water heater
  8. 99% energy, nearly no water is wasted.
  9. Built in advanced flow control modules, to regulate the water pressure automatically


Difficult to install, need 240 v power and heavy duty wiring

2. EcoSmart ECO 27 Electric Tankless Water Heater

EcoSmart Eco 11, 18, 27 and 36 series are all best outdoor electric tankless water heaters on the market in 2019, especially for the Eco 27, which is on the hot selling lists for a long period of time. They can be installed both indoor and outdoor. The nearer installation is, the faster hot water gets. So for outdoor installation, you can install it on the outside bathroom wall.

tankless water heater outside
outdoor tankless water heater




  • 140 degrees F temperature

This unit is perfect to be used in Northern America, where the incoming water temperature reaches as low as 37 degrees F; when in such low temperature, EcoSmart is still able to heat nearly 3 gallons per minute of water.

  • Multiple points of use

This unit is able to handle up to 6 gallons of water per minute, the official boasts that it is able to run 4 showers and one kitchen sink the same time and never run out of hot water.

  • Money saver

This outdoor tankless water heater is capable of saving up to 50% in water heating costs, the small shape also helps save much space for you. Advanced self-modulating technology controls water temperature smartly.


  1. Digital temperature control
  2. Copper and stainless steel components
  3. Unit is well made, heating elements are easy to be replaced
  4. Save 12 cubic feet after installation
  5. Save about 50% in water heating cost
  6. Self-modulating technology to ensure heater draws energy only when using it


  1. Disappointed service
  2. The temperature can not be set as right as EcoSmart promises

3. Sio Green IR260 Electric Tankless Water Heater

outdoor electric tankless water heater
top rated outdoor tankless water heaters




  • No corrosion

It has patented technology to ensure that outdoor electric tankless water heater gets no direct contact with metals. It will, in turn, prevent corrosion, limescale deposit, and calcium buildup. Therefore, it needs no or less maintenance in later using time.

  • 4 power levels

There are altogether 4 power levels can be adjusted, so you can choose the most suitable one for your family needs. The temperature of the water can also be adjusted easily. The LCD screen shows temperature accurately.

  • Infrared heating design

It has an infrared heating design to heat water only when you need it, and the fast heating time enables you to enjoy constantly hot water any time you want.


  1. Manual 4 power level
  2. Easy temperature adjustment
  3. Quick and easy installation
  4. No corrosion, no coils, and no scaling
  5. Stylish compact design


It is perfect to be used as a point of use but not whole house type


Above three are the best outdoor electric tankless water heaters we recommended for you, they are on the top list on the market of 2019 and all the performance are in brilliant condition. Of course, there are also many other types you can choose on Amazon, you can check for more information and price details on Amazon if you have an interest.


Can indoor electric tankless water heaters also installed outdoor?

Electric tankless water heaters are powered by electric only, no pipeline or venting kits are needed. Thus you can freely install them anywhere you want. But for some specific outdoor tankless water heaters, manufacturers suggest they should be used only for outdoor, if in such occasion, you can not use it as indoor types. On the contrary, the indoor tankless water heater can not be installed outdoor with specific requirement also.

If you are not sure, you can ask the manufacturer for help, they will help you a lot on installation.


The hot water waiting time is determined by the performance of the heating machine, but it is also greatly influenced by installation position; if you install it far away from using spot, then hot water needs to take a few seconds to flow through the pipe.

Therefore, for outdoor electric tankless water heater, we suggest it be installed outside wall of a bathroom or wherever you intend to use water, thus the waiting time can be shortened to large extent and water or electricity costs can be saved accordingly.


Tankless Water Heater Best Type
Best one for commercial use Stiebel Eltron Tempra 20 Plus Electric Tankless Water Heater
Smallest and lightest type EcoSmart ECO 27 Tankless Water Heater
Best point of use type Sio Green IR260 Electric Tankless Water Heater

If you want to get more information on products price, performance, and dimensions, etc, please feel free to check on Amazon, and there will always be a large discount on it to help save a large sum of money for you.