Tankless water heaters are great and affordable systems to heat water in a household or commercial establishment. As compared to tank-based water heater systems, tankless systems have the advantage of being able to provide continuous and on-demand hot water flow. Unlike tank-based water heaters, which can supply only the hot water that is stored in the tank, tankless systems can provide an endless flow of hot water whenever you need it.

Tankless systems also consume significantly less electricity. Tank-based systems tend to work even when there is no demand for hot water, whereas tankless systems work only when the hot water faucet is turned on. Since there is no tank present, the design of tankless systems is more compact and small. They can fit wherever you want to install them.

In this guide, we take a look at the best tankless water heaters and discuss who should get one.

Budget
Best-budget-
Rheem RTEX-13
4.5/5.0
4 pounds
Flow Rate 4.8 GPM
Low price, 5 year warranty, and compact design.
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Best Value
Best-value-
Takagi T-KJr2-IN-NG
4.6/5.0
38 pounds
Flow Rate 6.6 GPM
10 year warranty on heat exchanger and 5 years on parts.
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Top Pick
Top-value-
Rinnai RUC98iN
4.8/5.0
82 pounds
Flow Rate 9.8 GPM
Energy Star certification and good for cold climate areas.
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Tankless water heater systems have a wide variety of features. They are either electric or gas-powered, they have different flow rates, power or gas consumption requirements, and some of them even have fancy digital controls. Different models have different designs and warranty periods. All of these factors have to be looked into before purchasing the right tankless water heater system for your needs.

This guide will help you in making an informed decision about purchasing the best tankless water heater system, and you will also learn how to compare various systems that are available on the market. First, let us look at some of the features that various tankless water heater systems offer:

Now that we have all the various metrics and features of tankless water heater systems listed out, let us compare various models and how they stack up against each other in terms of these metrics:

10 Best Tankless Water Heaters Comparison Table

Make and ModelElectric or GasDigital Controls/ ThermostatPrice
Eccotemp L10GasNoCheck Price
Eccotemp FVI-12-LPGasYesCheck Price
EcoSmart ECO 11ElectricYesCheck Price
Rheem RTEX-13ElectricYesCheck Price
EcoSmart ECO 27ElectricYesCheck Price
Stiebel Eltron Tempra 24 PlusElectricYesCheck Price
Takagi T-KJr2-IN-NGGasHas a remote controlCheck Price
Rinnai RL75iNGasYesCheck Price
Rinnai RUC98iNGasYesCheck Price
Rheem RTGH-95DVLNGasYesCheck Price

Best Tankless Water Heater Systems By Budget:

Click below to get detailed information on each heater by price.

Tankless Water Heater Systems under $400

Tankless water heater systems that are reasonably priced have basic features. While they may not have high flow rate or good cold climate performance, they certainly offer a fairly decent heating function. If you are looking for a simple system, then these models below will interest you.

1. Eccotemp L10

Eccotemp L10View on Amazon

Editor’s Rating: 3.5/5

The Eccotemp L10 is a unique tankless water heating system. It is a small and portable system designed for travel. It can be installed pretty much anywhere, indoors or outdoors. You can even use it on an RV or if you go out camping. In fact, the system is field-tested for use at high elevations of 5,500 feet above sea level. You can even hook one of these up in your backyard and use it to bathe your dogs or other pets. The system uses a battery to power ignition.

The flow rate on this system is not very high, it only gives out about 2.6 gallons per minute. However, the flow rate is not the big draw for this system. It is the price. This is a low budget water heater. It is designed for specific situations. It may not give you the powerhouse capacity of more expensive systems, but the compact design and ease of installation are what the Eccotemp L10 offers. Given the features you get for the price you pay, we have given this system a rating of 3.5.

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Tech Specs
Part Number: L10
Item Weight: 27 pounds
Product Dimensions: 8 x 14 x 25.5 inches
Item model number: L10
Flow Rate: 2.6 GPM
Max Gas Input: 74,500 BTU
The Pros
Portable Design
Low Price
The Cons
Only 1 year warranty
Low Flow Rate of 2.6 GPM
No digital controls

2. Eccotemp FVI-12-LP

Eccotemp FVI-12-LPView on Amazon

Editor’s Rating: 3.8/5

The Eccotemp FVI-12iLP is a slightly better yet more expensive version of the Eccotemp L10. It is a no-thrills no-frills budget water heater system. It is good for household use, where the requirements are not very high. A single or small family may be able to get by, but this system is very basic indeed.

The Eccotemp FVI-12-LP has a flow rate of 3.6 gallons per minute. This can take care of a bathroom shower and one or two appliances. This system does have digital controls. It also comes with a 2-year warranty, as opposed to the 1-year warranty on the Eccotemp L10. It is a gas-powered model, running on propane. So make sure you have an input line to feed this system.

The Eccotemp FVI-12-LP is very price competitive, but at the same time, it also does not heat the water to the extent to which a more advanced system would. This factor is critical in cold climate areas. If your flow rate requirement is not very high and/or if you live in a temperate/hot climate area, then this system would be a decent budget option.

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Tech Specs
Part Number: FVI-12-LP
Item Weight: 29.4 pounds
Product Dimensions: 28 x 17 x 10.5 inches
Item model number: FVI-12-LP
Flow Rate: 3.6 GPM
Max Gas Input: 74,500 BTU
The Pros
Portable Design
Low Price
Digital Display and Control
The Cons
Only 2 years of warranty
Low Flow Rate of 3.6 GPM

3. EcoSmart ECO 11

EcoSmart ECO 11View on Amazon

Editor’s Rating: 3.8/5

The first thing that strikes about the EcoSmart ECO 11 is the lifetime warranty. It is the only tankless water heater system in this entire guide which comes with a lifetime warranty. The EcoSmart ECO 11 is an electric powered system. Hence, the installation process is not very extensive. Its compact design can also allow you to install it in tight spaces. The EcoSmart ECO 11 has a low flow rate of 2 gallons per minute and will be fit to serve basic water heating needs in a small household. One shower and a small sink will consume 2 gallons per minute quite easily.

This system does have some electronic controls. The digital temperature controller will allow the user to set or change the temperature of the water. Bear in mind that in colder environments, the heater will have to work doubly hard to heat the water. That, in turn, would lower the flow rate coming out of the system. Hence, if you live in a cold climate or your flow rate requirements are higher than a mere 2 gallons per minute, then you need to look for a more advanced system than the EcoSmart ECO 11. This system is a simple, basic, and cheap water heater for a low-end operating environment.

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Tech Specs
Part Number: ECO 11
Item Weight: 6.5 pounds
Product Dimensions: 12 x 8 x 4 inches
Item model number: ECO 11
Flow Rate: 2 GPM
Voltage/Power: 240V/13kW
Warranty Description: Lifetime
The Pros
Compact Design
Easy Installation
Low Price
Digital Controls
The Cons
Low Flow Rate of 2 GPM
Not suitable for cold climate areas

4. Rheem RTEX-13

Rheem RTEX-13View on Amazon

Editor’s Rating: 4.5/5

The Raheem RTEX-13 is one of the most popular electric tankless water heater systems. It scores well on the price as well as features aspects. Firstly, being an electric system, it has a compact design and light weight. It can be installed in small spaces. Secondly, the Rheem RTEX-13 offers a solid 4.8 gallons per minute of flow rate. Such a flow rate is good for a small to medium household with a couple of bathrooms. Along with the two showers in both the bathrooms, there will be some spare flow rate for operating appliances or a kitchen sink as well.

This system also has a sleek-looking digital thermostat. You can set the temperature and adjust the setting by turning an external knob. The Rheem RTEX-13 is also an energy efficient system. The specs say it is 99.8% energy efficient. Overall, this system offers the best flow rate in the budget price range. It also has good features which cover most of the basic household uses. The combination of all these factors makes this our top budget pick. We have given the Rheem RTEX-13 a rating of 4.5.

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Tech Specs
Part Number: RTEX-13
Item Weight: 4 pounds
Product Dimensions: 4 x 9 x 13 inches
Item model number: RTEX-13
Flow Rate: 4.8 GPM
Voltage/Power: 240V/13kW
Warranty Description: 5 years (heating chamber) ; 1year (parts)
The Pros
Decent Flow Rate of 4.8 GPM
Low Price
5 year warranty
Compact Design
Easy-to-install
The Cons
Not suitable for large households
Flow rate will drop in cold-climate zones

Tankless Water Heater Systems under $1000

Tankless water heater systems that are priced in the mid-range offer a balance of features vs price. They do have certain features which budget models do not offer, but the price is also a bit higher. If certain features such as a very high flow rate or a long warranty period are important for you, then select the models with those particular options. The information listed below will allow you to compare the pros and cons of mid-range models.

5. EcoSmart ECO 27

EcoSmart ECO 27View on Amazon

Editor’s Rating: 4.3/5

The EcoSmart ECO 27 is a great electric-powered tankless water heating system. It comes with a lifetime warranty similar to the EcoSmart ECO 11. That will ensure peace of mind for you throughout the operating life of your water heater system. This system has a flow rate of 3 gallons per minute at low temperatures, which is reasonably good for cold climate areas. Maximum flow rate in warmer temperature conditions is closer to 6 gallons per minute. The flow rate capacity is good enough to serve basic functions of a few showers and some kitchen sink usage. The EcoSmart ECO 27 runs on 240V and has a power watts rating of 27kW.

The digital control on this system allows you to change and set the water temperature in 1-degree increments. The EcoSmart ECO 27 also comes with a self-modulating technology, which allows the system to adjust its energy usage according to the demand for hot water. This makes the system very energy efficient. The compact design allows for installation in places with space constraints. The lifetime warranty on this system does come with some fine print, so make sure you read it before you purchase the EcoSmart ECO 27. Overall, it is a great mid-range option, offering a nice balance of features and favorable pricing.

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Tech Specs
Part Number: ECO27
Item Weight: 16.8 pounds
Product Dimensions: 3.6 x 17 x 17 inches
Item model number: ECO27
Flow Rate: 6 GPM (3 in cold weather conditions)
Voltage/Power: 240V/27kW
Warranty Description: Lifetime
The Pros
Compact Design
Easy Installation
Reasonable Price
Digital Controls with adjustment for 1 degree increments
Good Flow Rate
The Cons
Lifetime warranty comes with some fine print

6. Stiebel Eltron Tempra 24 Plus

Stiebel Eltron Tempra 24 PlusView on Amazon

Editor’s Rating: 4.2/5

The Stiebel Eltron Tempra 24 Plus is one of the best and most expensive electric-powered water heating systems. It has a stellar flow rate of 5.4 gallons per minute. Such a flow rate is good enough to handle the requirements of medium to large-sized households. As the name suggests, this system is German-engineered and has received some rave reviews in terms of quality and reliability. The unique part about the Stiebel Eltron Tempra 24 Plus is its Advance Flow Control. This special control system ensures that you get a continuous flow of hot water no matter how much the demand fluctuates.

This system has great digital controls as well, allowing you to accurately adjust the desired temperature of the water coming out. On the warranty front, the Stiebel Eltron Tempra 24 Plus has a 7-year warranty for leaks and 3 years for parts. While the warranty is not the longest in the list of heaters reviewed in this guide, the quality and reputation of this system ensure that you will have a hassle-free time using the Tempra 24 Plus. This system uses 15-20% less kW than a conventional tank-based heater, so it is a great system in terms of energy efficiency as well.

Overall, this is a great electric-powered system with high customer feedback. It is suitable for use in cold climates as well. Though we have reviewed the 24 Plus, there are other models with lower/higher power rating available as well. So, depending on your requirements, you can choose from a variety of options.

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Tech Specs
Part Number: Tempra 24 Plus
Item Weight: 16.1 pounds
Product Dimensions: 21.7 x 20.1 x 9.6 inches
Item model number: Tempra 24 Plus
Flow Rate: 5.4 GPM
Voltage/Power: 240V/24kW
Warranty Description: 7 yr (leak) ; 3 yr (parts)
The Pros
Compact Design
Easy Installation
Unique Advance Low Control
Energy Efficient
Good Flow Rate of 5.4 GPM
The Cons
Only 3 years warranty on parts
Price is a little expensive

7. Takagi T-KJr2-IN-NG

Takagi T-KJr2-IN-NGView on Amazon

Editor’s Rating: 4.6/5

The odd-sounding Takagi T-KJr2-IN-NG is our top pick in the mid-range tankless water heaters. It combines a great combination of reasonable price and features. This system is a gas-powered system. It comes with an Energy Star certificate. Hence, it is one of the most energy efficient gas-powered models in the market. It has an energy factor of 0.81 – 0.83. The Tagaki T-KJr2-IN-NG is able to monitor the incoming and outgoing water, thus minimizing fluctuations in the temperature of hot water that you use.

Since this system is a gas-powered one, it requires a vent to allow for the gas to escape. It requires at 4-inch category III stainless steel venting. The system has a solid flow rate of 6.6 gallons per minute. This makes it a good fit for use in cold climates and in medium-sized households. You can be confident of using multiple showers and some appliances simultaneously without a hitch.

The Takagi T-KJr2-IN-NG is also not the most compact system. It weighs 38 pounds and will take up some space. The installation costs on this system will be a bit expensive. But once you have everything up and running, not many gas-powered systems perform better than the Takagi T-KJr2-IN-NG.

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Tech Specs
Part Number: T-KJr2-IN-NG
Item Weight: 38 pounds
Product Dimensions: 6.7 x 13.8 x 20.3 inches
Item model number: T-KJr2-IN-NG
Flow Rate: 6.6 GPM
Voltage/Power: 140,000 BTU
Warranty Description: 10 yrs (heat exchanger) 5 yr (parts)
The Pros
High Flow Rate of 6.6 GPM
Digital Display and Control
10 years warranty on heat exchanger and 5 years on parts
Suitable for cold climates
The Cons
Expensive installation process

Tankless Water Heater Systems above $1000

Tankless water heater systems with extensive features are priced higher as well. They do cost a lot of money, but they offer you pretty much everything that you would need in a water heating system. The models listed below are some of the best in the industry, and if the price is not a concern, then this section is for you.

8. Rinnai RL75iN

Rinnai RL75iNView on Amazon

Editor’s Rating: 4.5/5

Rinnai is a trusted name in the tankless water heater industry. The RL75iN is a gas-powered water heating system which offers a flow rate of 7.5 gallons per minute. This kind of capacity is enough for a house with a few bedrooms and bathrooms. The high flow rate also means that you will not have a problem using this system in cold climate areas. A few showers and a kitchen sink being used simultaneously should be easy to do.

The Rinnai RL75iN has a digital control system. It allows the user to adjust the temperature of the water to the nearest degree. This system does need a vent for the gas to escape, and the installation can be a costly affair. The gas usage on this system is also high. It has a max input of 180,000 BTU. You will need to make sure you have a natural gas line available to hook up to the Rinnai RL75iN. If you want to use propane instead of natural gas, then you need to buy the model “75iP” instead of “75iN”.

The warranty on this system is quite good, offering 12 years on the heat exchanger and 5 years on parts. Additionally, there is a 1-year warranty on the labor costs associated with installation. The Rinnai RL75iN does not come cheap. But for the relatively high price that you pay, you can be sure of buying into a reliable and hassle-free system with a reputable brand attached to it. The system is also highly energy efficient and has an Energy Star certification.

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Tech Specs
Part Number: RL75iN
Item Weight: 65.9 pounds
Product Dimensions: 14 x 9.3 x 23 inches
Item model number: RL75iN
Flow Rate: 7.5 GPM
Voltage/Power: 180,000 BTU
Warranty Description: 12 yrs (heat exchanger) 5 yr (parts); 1 yr on labor for install
The Pros
High Flow Rate of 7.5 GPM
Digital Controls
Good for cold climate areas
Energy Star certification
The Cons
Very High Price
Bulky and heavy
High installation cost

9. Rinnai RUC98iN

Rinnai RUC98iNView on Amazon

Editor’s Rating: 4.8/5

The Rinnai RUC98iN is a more advanced version of the Rinnai RL75iN. This system has the highest flow rate among all the systems reviewed in this guide. It also has the highest energy efficiency that we have seen in our reviews. This stellar system also happens to be our top pick for tankless water heater systems in this guide.

The Rinnai RUC98iN has an incredible flow rate of 9.8 gallons per minute. That is good enough for a large house with multiple showers, kitchen, and appliances all running simultaneously. This system also has the reputation of being one of the quietest in the market. Even when running at full capacity, you will barely hear a sound, as the Rinnai RUC98iN goes about its heating process.

It has a very high energy factor of 0.96. One thing is for sure, your energy bills are not going to be very high with the Rinnai RUC98iN. It will indeed save you a lot, even though it costs quite a bit up front. Since this system is a gas-powered one, it requires venting. But Rinnai gives you two options, a concentric pipe or twin pipe PVC venting. This allows for some flexibility during the somewhat costly installation process.

The warranty on the Rinnai RUC98iN is 12 years for the heat exchanger, 5 years for parts, and 1 year for installation related labor cost. This is the same as the Rinnai RL75iN. If you are thinking long-term, then the Rinnai RUC98iN will save you a lot of money and run efficiently. However, you will have to pay a hefty price at the beginning to buy and set this system up.

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Tech Specs
Part Number: RUC98IN
Item Weight: 82 pounds
Product Dimensions: 10 x 18.5 x 26 inches
Item model number: RUC98IN
Flow Rate: 9.8 GPM
Voltage/Power: 199,000 BTU
Warranty Description: 12 yrs (heat exchanger) 5 yr (parts); 1 yr on labor for install
The Pros
High Flow Rate of 9.8 GPM
Digital Controls
Good for cold climate areas
Energy Star certification
One of the most energy efficient
The Cons
Very High Price
Bulky and heavy
High installation cost

10. Rheem RTGH-95DVLN

Rheem RTGH-95DVLNView on Amazon

Editor’s Rating: 4.7/5

Our final system in this guide is the Rheem RTGH-95DVLN. It is a gas-powered system with lots of technology. This system is another energy efficiency rockstar. It has 94% energy efficiency, and it is sure to save you money in the long run. If you are an environmentally conscious person, then this system fulfills that purpose as well. The flow rate on the Rheem RTGH-95DVLN is a strong 9.5 gallons per minute. That kind of flow rate can support a large house with multiple bathrooms, kitchen, and appliances. You will not have to worry about flow rates ever with this system.

Its electronic control system is one of the best. The electronics even has a self-diagnostic mode. With such controls, you can be sure to sit back and enjoy the hot water without worrying about maintenance or operational issues. There is a water saving setting as well, which limits the flow of water till the temperature threshold is reached. Lastly, this system also has a minimum flow rate and activation point feature. What this does is gives out hot water even with very low demand. Many other water heating systems give out hot water only when there is enough demand beyond a certain minimum level. With the Rheem RTGH-95DVLN, that is not the case.

In terms of warranty and other features, this system is similar to the Rinnai models reviewed above. More details can be seen in the technical specifications table below. Overall, if you have the money to spend and the love for technology, then you will love the features that the Rheem RTGH-95DVLN offers.

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Tech Specs
Part Number: RTGH-95DVLN
Item Weight: 79 pounds
Product Dimensions: 18.5 x 9.8 x 27.5 inches
Item model number: RTGH-95DVLN
Flow Rate: 9.5 GPM
Voltage/Power: 199,000 BTU
Warranty Description: 12 yrs (heat exchanger) 5 yr (parts); 1 yr on labor for install
The Pros
High Flow Rate of 9.8 GPM
Digital Controls
Good for cold climate areas
Energy Star certification
One of the most energy efficient
The Cons
Very High Price
Bulky and heavy
High installation cost

So there you have it, we have reviewed 10 amazing tankless water heater systems to help you decide which one is the best for your needs. Remember to compare the different features, warranty periods and pricing. With all the information mentioned above, you are sure to make an informed decision. Good luck!