10 Best Tankless Water Heaters – Reviews & Buying Guide

Best Tankless Water Heater

The tankless water heater is one of the most reliable types of heaters on the market.

Due to its small and slim form factor, you will have no difficulty installing this heater in any bathroom as it does not consume a lot of space.

Furthermore, installation is very easy for absolute beginners. You also have the option to choose between an electricity-powered tankless water heater and a gas-powered model for your convenience.

If you are fresh on the market for the best tankless water heater for the money, then we have you covered in our review below.

We have hand-picked some quality heaters and give you an overview. Let’s get to it right now!

10 Best Tankless Water Heaters – Reviews

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​PRODUCT

​FEATURES

EcoSmart ECO 11

1. EcoSmart ECO 11

  • Energy efficient at 13 kW
  • Flexible. Comes in different sizes
  • Front digital display
  • Easy to adjust the water temperature
Rinnai RUC98iN Ultra Series

2. Rinnai RUC98iN

  • The superior flow rate of 9.8 GPM
  • Safe to use indoors
  • Excellent build construction
  • Easy to adjust water flow and temperature
Stiebel Eltron 36 Plus

3. Stiebel Eltron 36

  • Modern and aesthetically pleasing
  • Available in different sizes
  • Solid warranty by the manufacturer
Rheem RTGH-95DVLN

4. Rheem RTGH-95DVLN

  • The superior flow rate of 9.5 GPM
  • Comes with a digital remote controller
  • 94% energy efficient
Takagi T-KJr2-IN-NG

5. Takagi T-KJr2-IN-NG

  • Heavy duty and reliable
  • Above average water flow of 6.6 GPM
  • Wall-mounted remote control
Rheem RTEX-13

6. Rheem RTEX-13

  • 99.8% energy efficiency
  • Easy to read front digital display
  • Very easy to install
Rinnai RL75IN

7. Rinnai RL75IN

  • Superior build construction
  • The excellent water flow rate of 7.5 GPM
  • Digital display shows error codes
EccoTemp L10

8. EccoTemp L10

  • Most affordable solution
  • Very low-temperature range of 50°F
  • The flame indicator at the front
Atmor AT-910-27TP

9. Atmor AT-910-27TP

  • Small and compact
  • High performing and heats water fast
  • Easy to adjust water temperature
Marey Gas 10L

10. Marey Gas 10L

  • Cost-effective pricing
  • Easy to adjust temperature and water flow
  • No experience for the installation

PRODUCT

1. EcoSmart ECO 11

EcoSmart ECO 11
  • Energy efficient at 13 kW
  • Flexible. Comes in different sizes
  • Front digital display
  • Easy to adjust the water temperature

2. Rinnai RUC98iN

Rinnai RUC98iN Ultra Series
  • The superior flow rate of 9.8 GPM
  • Safe to use indoors
  • Excellent build construction
  • Easy to adjust water flow and temperature

3. Stiebel Eltron 36

Stiebel Eltron 36 Plus
  • Modern and aesthetically pleasing
  • Available in different sizes
  • Solid warranty by the manufacturer

4. Rheem RTGH-95DVLN

Rheem RTGH-95DVLN
  • The superior flow rate of 9.5 GPM
  • Comes with a digital remote controller
  • 94% energy efficient

5. Takagi T-KJr2-IN-NG

Takagi T-KJr2-IN-NG
  • Heavy duty and reliable
  • Above average water flow of 6.6 GPM
  • Wall-mounted remote control

6. Rheem RTEX-13

Rheem RTEX-13
  • 99.8% energy efficiency
  • Easy to read front digital display
  • Very easy to install

7. Rinnai RL75IN

Rinnai RL75IN
  • Superior build construction
  • The excellent water flow rate of 7.5 GPM
  • Digital display shows error codes

8. EccoTemp L10

EccoTemp L10
  • Most affordable solution
  • Very low-temperature range of 50°F
  • The flame indicator at the front

9. Atmor AT-910-27TP

Atmor AT-910-27TP
  • Small and compact
  • High performing and heats water fast
  • Easy to adjust water temperature

10. Marey Gas 10L

Marey Gas 10L
  • Cost-effective pricing
  • Easy to adjust temperature and water flow
  • No experience for the installation

1. EcoSmart ECO 11 Best Electric Tankless Water Heater

Editor's Rating: 4 out of 5 stars (4 / 5)

EcoSmart ECO 11
  • Flow Rate: 1.5 GPM
  • Fuel: Electricity
  • Temperature Range: 67°F to 105°F

When choosing the ideal electric tankless water heater, there are multiple factors to take into account.

You need to consider your need; it’s efficiency, the quality of the tankless heater itself as well as its performance and reliability.

And even if most of the time the best electric tankless water heater usually tends to be a model with the highest flow rate, this is not always true all the time.

This is where models like the EcoSmart really shines. Despite having a flow rate of only 1.5 GPM, this model is still able to outshine other more premium grade units.

First off, the price of the EcoSmart is significantly lower when compared to the competition. It is also available in different sizes to suit the different need.

Furthermore, it is backed by a lifetime warranty by the manufacturer, and it is very energy efficient which means that it will not inflate your electricity bill.

All those factors make this model an excellent choice to consider, especially for those who don’t have a very big budget to spend on a tankless water heater.

Pros:

  • Energy is efficient at 13 kW. Consumes less electricity
  • Available in different sizes to suit your water heating need
  • Very easy to install by absolute beginners
  • Front display shows the water temperature at all times

Cons:

  • Temperature range is limited
  • Weak flow rate when compared to other models

2. Rinnai RUC98iN Ultra Series – High Performance & Heavy-duty

Editor's Rating: 4.4 out of 5 stars (4.4 / 5)

Rinnai RUC98iN Ultra Series
  • Flow Rate: 9.8 GPM
  • Fuel: Gas
  • Temperature Range: 98°F to 140°F

In terms of performance, it is difficult to beat the Rinnai RUC98iN.

Indeed, this model has a flow rate of 9.8 GPM which makes it the most performing model in terms of water heating capacity that you will encounter in this tankless water heater review.

Furthermore, this unit comes with a practical front LCD display that will show you the temperature of the water.

It also has many adjustable controls like the ability to control the temperature of the water as well as the flow rate. All those controls are fully waterproof, no problem.

As expected from Rinnai, the build construction of this heater is superb and made from a very durable and long-lasting material.

In addition, the manufacturer says that this unit can also safely be installed indoors even if it is a gas-powered heater.

Since this is a gas-powered tankless water heater, at the top you will find a PVC vent for the venting system.

All in all, if you need a performing and heavy-duty tankless water heater that will be able to heat any amount of water very quickly, then this model is an excellent choice.

Pros:

  • The superior flow rate of 9.8 GPM
  • Can safely be installed indoors even if it is a gas-powered water heater
  • Excellent build construction. Durable and long-lasting
  • Easy to adjust the water temperature

Cons:

  • The price. It is a very expensive model
  • Venting system does not come with this heater

3. Stiebel Eltron 36 Modern & Aesthetically Pleasing

Editor's Rating: 4.4 out of 5 stars (4.4 / 5)

Stiebel Eltron 36 Plus
  • Flow Rate: 4.5 GPM
  • Fuel: Electricity
  • Temperature Range: 86°F to 140°F

Stiebel Eltron is undoubtedly one of the best tankless water heater brands on the market. They make excellent tankless water heaters as well as other high-quality shower accessories. This current model is no different.

It is aesthetically pleasing and looks very modern. When installed in the bathroom, it will immediately uplift its looks and adds some modernity to it.

Additionally, controlling the various settings like water temperature and water flow is very easy with this tankless water heater.

You can do so with the wide range of controls available right at the front of the unit. There is a wide display that shows you the flow rate as well as the current water temperature which is very neat.

But what we like the most about this tankless water heater is that it comes in different styles and sizes to suit your need as well to the style of your bathroom.

Also, the recommended water temperatures for specific uses are also printed right at the front of the heater for better ease-of-use.

Whether you have a high-water heating demand or need a model for casual use, you will find it with the Stiebel Eltron.

Installation is very easy and can be done by absolute beginners. This tankless water heater also comes with no less than 7 years warranty on leakages and 3 years warranty on parts which is awesome.

Pros:

  • Modern and aesthetically pleasing
  • Flexible. Available in a wide range of styles and sizes
  • Easy to install by beginners
  • Solid warranty on leakages and parts by the manufacturer

Cons:

  • The flow rate is pretty average

4. Rheem RTGH-95DVLN – High Performing & an Efficient

Editor's Rating: 4.2 out of 5 stars (4.2 / 5)

Rheem RTGH-95DVLN
  • Flow Rate: 9.5 GPM
  • Fuel: Gas
  • Temperature Range: N/A

Many users of the Rheem RTGH-95DVLN rank it as one of the best gas tankless water heaters on the market. This is because this unit has a very high flow rate of 9.5 GPM.

Which shows that this heater has a high-water heating capacity and able to work with any type of showerhead.

It will work comfortably with your regular handheld showerhead to a full-size rainfall showerhead.

Moreover, the manufacturer rates this model as 94% energy efficient which means that it does not waste a lot of gas.

The bottom line is, you will consume less gas with this unit, so it is more economical to maintain in the long run. It has also been tested by the manufacturer to be perfectly safe to use.

The only caveat we note with this product is that it does not have a display to show the water temperature or water flow. However, it does come with digital remote control and 10 feet of thermostat wire to help in the installation.

Pros:

  • You get a digital remote control with this purchase
  • 94% energy efficient. Consumes less gas
  • Comes with 10 feet of thermostat wire

Cons:

  • It is the most expensive tankless water heater in this review
  • No temperature or water flow display

Notes

This water heater is ideally installed outside of the bathroom. All functions like water temperature and water flow can then be controlled inside using the provided digital remote control.

5. Takagi T-KJr2-IN-NG – Reliable & Heavy-duty

Editor's Rating: 4.3 out of 5 stars (4.3 / 5)

Takagi T-KJr2-IN-NG
  • Flow Rate: 6.6 GPM
  • Fuel: Gas
  • Temperature Range: 113°F to 140°F

There is nothing fancy about this Takagi tankless water heater. In fact, it is quite modest in terms of looks as it looks like a regular shower heater.

However, under the hood hides a true beast because this tankless water heater has a flow rate of 6.6 GPM and a versatile temperature range.

It is able to heater water quite fast, even if the low-temperature range of 113°F is not the best we have seen.

While this tankless water heater does not have a temperature or water flow rate controller built into it, you get a remote wall-mounted controller with this purchase.

This makes it more convenient as you can now control this water heater anywhere you want.

But what this tankless water heater is reputed for is its ease-of-use and ease of installation. If you have never installed a tactless water heater before, then you will have no problem with this unit.

The only caveat is that it does not come with a 4 inches venting system and you will have to install it separately.

Pros:

  • Reliable and heavy-duty
  • Above average flow rate of 6.6 GPM
  • Easy to install by absolute beginners
  • Comes with a wall-mounted remote control

Cons:

  • Not the best low water temperature range

Notes

We recommend this tankless water heater only for those who live in a fairly hot climate because of its weak low-temperature range of 113°F

6. Rheem RTEX-13 – Very Energy Efficient

Editor's Rating: 4.2 out of 5 stars (4.2 / 5)

Rheem RTEX-13
  • Flow Rate: 3.17 GPM
  • Fuel: Electricity
  • Temperature Range: 80°F to 140°F

The Rheem RTEX-13 is a top-rated tankless water heater that has been designed with energy efficiency in mind. In fact, according to the manufacturer, this heater has an energy efficiency of 99.8%.

Also, despite being less expensive than other models, it is full-featured and comes with functions like a display and adjustable controls. The display will show you the water temperature only.

Further, installation is very easy as this water heater uses standard threaded connectors. It comes with all installation accessories so you will not have to purchase them separately.

Its flow rate of 3.17 GPM is definitely not the best we have seen, but it is still strong enough to drive most showerheads on the market with great ease.

If you are looking for an easy to install and easy to use tankless water heater, the Rheem RTEX-13 is an excellent choice to consider.

All things considered; this unit is the ideal solution especially for those who do not have a high-water flow in their bathroom.

Pros:

  • 99.8% energy efficiency
  • Front display shows the water temperature
  • Easy to adjust the water temperature
  • Comes with all installation accessories

Cons:

  • Not the best flow rate at 3.17 GPM

7. Rinnai RL75IN – Durable & Long-lasting

Editor's Rating: 3.9 out of 5 stars (3.9 / 5)

Rinnai RL75IN
  • Flow Rate: 7.5 GPM
  • Fuel: Gas
  • Temperature Range: 98°F to 140°F

The Rinnai RL75IN concentrates on build construction. With its high flow rate of 7.5 GPM, this is a heavy-duty tankless water heater that is ideal for a large family who constantly needs to switch on the water heater for a shower.

It is reliable and able to heat water quite fast, making it an excellent model for those who live in temperate environments where the water is very cold.

Moreover, this tankless water heater has an outstanding feature that allows it to display an error code on its display.

This will allow you to troubleshoot any problems like poor water flow. Of course, the display also shows the temperature of the water as well.

Pros:

  • The decent flow rate of 7.5 GPM
  • Excellent build construction. Durable and long-lasting
  • The display shows water temperature and errors

Cons:

  • The price. It is expensive
  • The venting can be difficult to install by beginners

8. EccoTemp L10 – Most Affordable Solution 

Editor's Rating: 3.8 out of 5 stars (3.8 / 5)

EccoTemp L10
  • Flow Rate: 2.6 GPM
  • Fuel: Gas
  • Temperature Range: 50°F to 140°F

Not everybody has hundreds of dollars, if not thousands to spend on a tankless water heater.

This is where models like this EccoTemp L10 comes into play. Indeed, the L10 is the best tankless water heater based on price only.

Furthermore, this unit still comes with temperature control as well as with a water flow controller knob.

It also has safety features like a 20-minute safety shutoff that will automatically shut off this water heater. This feature is in place in case you forget to turn off the water flow.

Also, since this tankless water heater uses common 1/2-inch threaded connectors, you will have no problem installing it in your bathroom.

If you are on a short budget and need a reliable and performing tankless water heater, then the EccoTemp L10 is definitely worth considering.

Sure, it does not have the aesthetics or features of more premium an expensive tankless water heater, but it definitely gets the job done!

Especially with its low temperature of 50°, F is which shows that it is able to heat very cold water with ease.

This model is definitely ideal for those who live in an environment where the winter is particularly severe.

Pros:

  • The most affordable solution in this review
  • The excellent low temperature of 50°FThe flame indicator at the front
  • Easy to install by absolute beginners

Cons:

  • The weak flow rate of 2.6 GPM

9. Atmor AT-910-27TP Slim, Compact & Highly Performing

Editor's Rating: 3.6 out of 5 stars (3.6 / 5)

Atmor AT-910-27TP
  • Flow Rate: 5.1 GPM
  • Fuel: Electricity
  • Temperature Range: 90°F to 135°F

This Atmor electric tankless water heater has a mix of many interesting features. For one, it is small and compact which means that it will not consume a lot of space when installed.

Therefore, you can easily install it in a small bathroom like an RV bathroom where space is always limited.

Also, it has a decent flow rate of 5.1 GPM which is definitely not the best we have seen but still more than adequate for most people.

The temperature range of 90°F to 135°F is also quite versatile as it shows that this tankless water heater will have no problem dealing with common temperatures that people use in their shower.

All in all, despite its small size, this unit by Atmor remains one of the best electric tankless water heaters on the market.

Pros:

  • Small and compact. Does not need a lot of space
  • High performing and able to heat water fast
  • Digital display and easy to adjust the temperature

Cons:

  • Not as durable when compared to other models

10. Marey Gas 10L Simple & Effective

Editor's Rating: 3.4 out of 5 stars (3.4 / 5)

Marey Gas 10L
  • Flow Rate: 3.1 GPM
  • Fuel: Gas
  • Temperature Range: N/A

One problem with many tankless water heaters is that they tend to be complicated, both in terms of usage and in terms of installation.

This is definitely not a problem with this Marey Gas 10L as it is a simple but yet highly effective tankless water heater. It is easy to install and even easier to use.

There are 3 knobs at the front of this water heater that allows you to adjust various functions like the water flow and water temperature.

Since this is a simple tankless water heater, the installation is equally simple. If you have no experience of installing a water heater before, you will have no problem with this Marey model.

Not to mention that the price is also very cost-effective and hard to beat.

Pros:

  • Cost-effective pricing
  • Simple and yet highly effective water heater
  • Easy to install by absolute beginners
  • No electrical installations to make. Powered by gas

Cons:

  • No water temperature display

Advantages/Disadvantages of Tankless Water Heater

Pros and Cons of Tankless Water Heater

As with everything, the tankless water heater has both its advantages and disadvantages. Here are a few of the most common pros and cons:

#1. Advantages:

Energy Saving: Since the tankless water heater only needs to heat water it receives on demand and not a whole water tank, it consumes less electricity or gas to do so.

This makes it more cost-effective when compared to other types of water heaters on the market

Compact Design: One of the biggest advantages of the tankless water heater is its small and compact design.

You will have no problem installing this heater in the bathroom with a limited installation space.

Clean Water: There is no tank to store water in the tankless water heater.

Therefore, minerals, rust, and other debris do not accumulate in this type of heater which makes it outputs only clean water.

Endless heating: The tankless water heater will continue heating the water as long as the device is turned on.

So, it provides you with an endless hot water supply for you to shower. Which is highly beneficial especially if you need to take a shower for an extended period of time.

Ease of Installation: You will have absolutely no problem installing the tankless water heater because it is extremely easy to install.

Furthermore, most models use standard 1/2-inch connectors for the installation.

#2. Disadvantages 

High Initial Cost: When compared to other types of water heaters on the market, the tankless water heater is usually much more expensive. So, it has a high initial cost.

Water Flow: You will need a consistent water flow for the tankless water heater to work reliably.

If you do not have a high enough water pressure, then you will have difficulty regulating the temperature of this type of heater.

Power Usage: The electric tankless water heater will need a lot of electricity to the heater the water.

If you are using the tankless water heater in an RV, you may need to make sure that you have this kind of power for your heater.

Gas Vents: In case you choose to go with a tankless gas water heater, then you need to install the venting system for your heater. This venting system is usually quite expensive.

How to Buy the Best Tankless Water Heater

How to Buy the Best Tankless Water Heater

#1. Size

Finding the right size for this type of heater is different than a water heater that comes with a tank. With the tankless water heater, “size” is related to the flow rate of the heater.

The higher the flow rate of the tankless water heater, the bigger the “size” can be assumed to be.

With that logic, a tankless water heater that has a flow rate of 8 GPM will have a bigger size than a water heater with a flow rate of 2 GPM.

For most people, a tankless water heater that has a flow rate in the range of 4 GPM to 8 GPM is more than enough.

However, if you enjoy a high-water pressure in your bathroom, then it is always best to go with a water heater that has the highest flow rate that you can afford.

Yes, the higher the flow rate of the tankless water heater, the higher the price will also be. At least, most of the time.

Therefore, the size of your tankless water heater will also depend on your budget. Choose a model that strikes the right balance.

#2. Temperature Rise

As its name suggests, the temperature rise is simply how fast the temperature of the water rises.

If you live in a temperate region where the water is very cold, then you need to go with a tankless water heater that has a high-temperature rise.

This is because you do not want to wait too long for the temperature of the water to heat up. You want it to heat up as fast as possible.

The temperature rise is usually the remainder of the desired temperature limit subtracted to the groundwater temperature.

For example, if the temperature of your water outlet is 40°F and you adjusted the tankless water heater to a maximum of 120°F, then the temperature rise is 120°F - 40°F = 80°F.

In short, the best tankless water heater that you can purchase is simply a model that has the highest temperature rise.

Note that the temperature rise is also dependent on the water flow as well as the temperature of the groundwater.

A smaller flow rate will result in a higher temperature rise, but the showering experience will be less pleasurable because obviously there is less water coming from the showerhead.

#3. Fuel Type

Most tankless water heaters use either 2 types of fuels. Electricity which is an alternate fuel and natural gas which is usually propane gas.

When choosing between those 2 types of fuel, you will need to take into account your need and purpose.

Additionally, a tankless water heater powered by natural gas is generally more versatile because you can use it in places where there is no electricity.

The contrary is not true because an electric tankless water heater is 100% dependent on electricity.

#4. Installation Cost

The installation cost is usually minimal if you choose to go with an electric tankless water heater.

However, for those opting for a tankless water heater powered by natural gas, then you will need to take into account the venting system.

This venting system is simply a way to evacuate all the toxic gases produced during the process of heating the water.

It is very important, and you will be charged extra by your professional expert during installation in case you are not installing the heater yourself.

#5. Climate

You also need to take your climate into account when purchasing a tankless water heater.

This is because if you live in a very cold and temperate climate, then the temperature of the water will be very low.

So, you will need a water heater that is performing and has a high-temperature rise so as to heat up the water as fast as possible.

#6. Brand

Since the tankless water heater is often times quite expensive, many people are tempted to go with a no-name brand so as to save money.

We do not advise you do this because a no-name tankless water heater is usually of lower quality.

Additionally, it is less safe, less efficient, and not as durable and long-lasting as a reputed model.

So, you will benefit more in terms of reliability and fuel cost with a tankless water heater made by a reputable brand in the long term.

Conclusion

One of the biggest advantages of the tankless water heater is its slim and compact form factor. Despite this slim shape, it is still a heavy-duty heater that is able to heat water fast and reliably.

Furthermore, due to its small size, it will not occupy a lot of space in the bathroom and can be installed in places like an RV bathroom where space is limited.

Moreover, the tankless water heater is powered by either electricity or gas depending on the model you choose, so it is quite versatile.

Hopefully, by now you have gone through our tankless water heater review above and already decided on a model.