Purchasing a tankless water heater can help save money spent on electric or gas bills yearly. Some heaters are sourced by electrical systems and others by natural gas.

We have carefully reviewed the best tankless water heaters for you and have listed the most important factors to consider before buying a tankless water heater.

Best Tankless Water Heater Reviews


Takagi T-H3S-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 8-Gallon Per Minute
Takagi T-H3S-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 8-Gallon Per ...
5.0 out of 5 stars
View on Amazon


  • Size: Medium
  • Source of Power: Gas
  • Temperature range: 100 to 180 degrees Celsius
  • Level of Sound: 55dB
  • Rate of Flow: 10 gallons per minute
  • Low gas Emissions, Computerized Safety Settings
  • Energy conservation, space saving, endless supply of hot water


The Takagi Tankless Heater is a perfect option available if you use a gas system at home. All you have to do in order to pass hot water to all rooms in your house is to tap a button on the heater to turn it on, instead of lighting and relighting as with other heaters. This model was designed by Takagi for people who need much hot water over a long period.

The wonderful thing about this model is its being able to supply an endless amount of hot water for your needs. Whether you like to do laundry after bathing or your family takes multiple showers daily, there’ll be enough water for you. It also has a compact size which helps to save space in your home.

There are few new features added by Takagi to ensure your home and family is safe.  Asides the confident feeling of the heater not catching fire because of the absence of pilot light, you need not worry about gas emissions being released which might cause sickness. Its safety settings are computerized, and it meets every standard to have a low emission label.

The quantity of hot water produced by the Takagi T-H3 depends largely on the ground water temperature in your environment. In warm climates, it can produce enough water to serve four bathrooms, while in cold climates; you may not get enough water for more than three bathrooms.

The Takagi T-H3 water heater has temperature range which can be adjusted between 100 and 180 degrees Fahrenheit. With lower sound rating which some people like, its rate of flow per minute is 10 gallons each minute.

Rheem RTG-64XLN 6.4 GPM Low NOX Outdoor Tankless Water Heater (Gas)

Rheem RTG-64XLN 6.4 GPM Low NOx Outdoor Tankless Natural Gas Water heater
Rheem RTG-64XLN 6.4 GPM Low NOx Outdoor Tankless Natural Gas Water heater
3.6 out of 5 stars
Not available
View on Amazon


  • Source of Power: Hard-wired or plug, 120v AC
  • Method of Installation: Wall-mounted, outdoor
  • The heat exchanger is full copper (1st of its kind), Unique film wrap to protect heat exchanger.
  • Rate of flow: 6gallons per minute, 35-degree rise
  • Included: 10 ft thermostat, remote control (digital)


Rheem is a very popular name in home appliances market. It is designed with a metal cabinet which gives the internal components protection. With this tankless water heater, you are sure to save some good bucks totaling up to $200 yearly on your energy bills.

This Rheem water heater is designed for mounting and installation on outdoor walls. There is an option plug that comes with it which allows it to be used with any 120V power source outdoors, but it can also be hard wired into an electric system. Professional help is usually needed for hard wiring. For hard wiring, Rheem recommends outdoor use only.

The Rheem tankless water heater is the first of its kind to produce a heat exchanger which is made completely from copper. This keeps the water hot and allows you to enjoy hot water from the bath. There is also an Overheat film wrap which protects the heat exchanger and helps to avoid rusting.

It also comes with a remote control (digital) which helps to control the water temperature and other adjustments and settings without having to touch the water heater. The batteries of the remote control can be easily replaced if it stops working. The remote can be used to adjust settings from outside or inside your house.

This Rheem tankless water heater has a 6 gallons/minute flow rate that ensures you always get the exact quantity of water you need. The model has a 35 degree Fahrenheit rise which allows for adjustment of the temperature of the water either up or down according to your need.


Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas
Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas
4.2 out of 5 stars
View on Amazon


  • 6 gallons per minute flow rate
  • 140000 BTU
  • 81-0.83 energy factor
  • Thermosistors for monitoring temperature
  • 38 pounds weight


For a second time, Takagi makes this list with this tankless water heater meant for indoor use, which has about the same characteristics as its top-ranked and more expensive model does. The size of this model is more compact, so the space needed for a water heater is reduced. This model weighing less than thirty pounds is much lighter in weight compared to other models which we found.

This model has two certifications; Energy Star guarantees that you will save money on utility bills and consume less water. The other certification ensures that you won’t experience the hassles or frustrations that other model users do.

The design is made of heavy-duty coupling at the bottom. The couplings allow easy installation of the water heater and to shut it off in the case of emergency. To stop the power or water flow, the couplings can easily be unscrewed.

The Takagi model has an energy factor which reaches as high as 0.83. This helps you to know that the water heater produces a large quantity of hot water when compared to the quantity of energy it expends daily.

Some unique components are added to this Takagi model to monitor the heater and the hot water temperature. In other models, the temperature can change during the day and drop below the level you prefer. These unique components will monitor and regulate the water to make sure that the temperature of the water does exceed or go below the level you set it, to avoid taking shower which is cold or boiling.


EcoSmart ECO 27 Electric Tankless Water Heater, 27 KW at 240 Volts, 112.5 Amps with Patented Self Modulating Technology
EcoSmart ECO 27 Electric Tankless Water Heater, 27 KW at 240 Volts, 112.5 Amps with Patented Self Mo...
4.0 out of 5 stars
View on Amazon


  • Compact size, advanced design
  • Better degree increment in temperature display
  • Saves about 50% of energy bills
  • Copper, stainless components for durability and efficiency
  • 8 pounds weight


Ecosmart appears multiple times on the list because of the efficiency and affective essential of its tankless heater models. The ECO27 has loaded features which can slash your energy bills halfway and temperature control (digital) to enable you set the temperature of the water.

The ECO27 design is more modern than some other Ecosmart models. Right in the middle of the heater, there is a silver knob and also at the top is a digital display. As the water temperature is being adjusted, the display shows exactly what degree it is being set. Also, when the knob is turned to the right, the temperature increased and when it’s turned to the left, the temperature decreases. To get a preferred temperature, you need to focus on the digital display.

You can switch between the Celsius and Fahrenheit measurement by holding down the knob and touching the power button simultaneously, and then moving the silver knob back. Though it has between eighty and one hundred and forty degrees Fahrenheit temperature range, it is recommended to stick to a maximum of 110 degrees temperature.

For the installation of the ECO27, 240 volts and 40 watts breakers are needed. Electrical systems that have less power can’t support this model and can cause an overheating of the electrical system as a whole. Asides the ECO27 being compact enough to take less space, it is also made of brass and copper which are durable enough to last for a long period.


EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology
EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Tech...
4.0 out of 5 stars
View on Amazon


  • Little degree increments in temperature control display
  • Endless supply of hot water
  • Save about 60% on energy costs
  • Weighs 6.5 pounds, 240V


The ECO11 Tankless Water is another Ecosmart model that makes our list. Though it doesn’t work on gas systems but only electric systems, it can help to save over 60% of the energy bills in your home. Ecosmart also gives a lifetime warranty for people who use it in residential apartments.

One common problem with tankless heaters is their lack of tanks which limits the quantity to be used at a time. This model is designed by Ecosmart to provide as much quantity of water is desired. The water is heated up to the selected temperature and ensures the water keeps flowing from the faucet or tap.

The ECO11 is very easy to use. Unlike many other models which can get you confused with many different buttons and knobs, this water heater has only one button at the front. To switch on the heater, press te knob and hold for 3 seconds, and to switch it off, hold down the button again for three more seconds. To adjust the water temperature up or down, wind the knob to the left or right.

You do not have to worry about the water being a little hotter than you desire. It has a digital display at the front which shows the temperature that you set. When the knob is turned to the right, the display will show that the temperature has been lowered and vice versa.

For installation of the ECO11, a 125 amps electrical panel, AWG wire and a double pole 60 amps breaker are needed to ensure the water heater works fine and doesn’t cause an overheating of the electrical system.


Rheem RTE 9 Electric Tankless Water Heater, 3 GPM
Rheem RTE 9 Electric Tankless Water Heater, 3 GPM
3.4 out of 5 stars
Not available
View on Amazon


  • Rugged copper/brass heat exchanger
  • 1 pounds weight,
  • Modulating power
  • LED lights indicate standby and active mode
  • Flow rate: 3 gallons per minute


The Rheem RTE9 Electric Water Heater provides the desired quantity of hot water you need. It is made up of a strong metal cabinet which protects the wires and other important components inside. It has two hook ups on both sides of the box for quick installation.

One of the major features of this model is the simple design, with basic lights and a knob at the front. When the knob is turned to the left, the temperature increases to medium setting, and then follows the highest setting. The actual water temperature can’t be seen except the general setting which some people may not like.

There is a red and a green button at the front to help you know whether the system is active. The system is active if the red light is on, and on standby mode if the green light is on. When you do not use or need hot water, the water heater will be in standby mode.

This Rheem model has a heat exchanger made of copper which will last longer than other types. There is a film on the exchanger’s surface to protect the metal from rust. The heat exchanger also has brass components to make it more durable.

This model more hot water than you need, as it has 9 gallons per minute flow rate. There will be enough hot water to do dishes, take showers and do some laundry before the hot water is exhausted. It also weighs less than 8 pounds, which is compact for most homes.


Ecosmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Technology
Ecosmart ECO 18 Electric Tankless Water Heater, 18 KW at 240 Volts with Patented Self Modulating Tec...
4.0 out of 5 stars
View on Amazon


  • Simple to use, durable
  • Lifetime warranty
  • Self-modulate technology, save about 60% in energy bills
  • Endless supply of hot water
  • Saves about twelve cubic ft of space, 14 pounds weight


The Ecosmart ECO18 electric tankless water heater can easily switch between Fahrenheit and Celsius within few seconds. It is easy to use and is perfect for people who like something basic which still produce gallons of water as needed. It has a simple design that anyone can use before getting in the shower.

It has a digital display and a silver knob. It is preset in Fahrenheit, but when the knob is held down and turned left or right, the settings can be seen in Celsius. EcoSmart is among few companies that give room for 1-degree temperature adjustment at a time. When the knob is turned left, the temperature increases, and vice versa.

The ECO18 model has a flow technology that self-modulates; this distinguishes this model from others. The technology monitors the temperature needed, and the quantity of water used and then adjusts the system to consume less power automatically. This helps to slash up to 60 % of utility bills.

This model also has a thermostat which can be reset automatically. This is perfect for those who like various water temperatures. When the central button is held down for 3 seconds, the heater resets itself automatically. The desired temperature can then be selected by adjusting the knob.

EcoSmart issues a lifetime limited warranty on this model which covers most of its components and parts.


Lotus LTS-3HP 3.5kW/120V Electric Tankless Water Heater
Lotus LTS-3HP 3.5kW/120V Electric Tankless Water Heater
2.8 out of 5 stars
View on Amazon


  • 5 gallons per minute
  • 3kw, 110V(No plug, Hardwire only)
  • Designed for only single sink
  • 4 pounds weight


The Lotus electric tankless water heater can produce as much hot water as you need. The reason it ranks low on our list is that it is perfect in warmer climates. The Lotus heater may not produce the desired temperature, depending on the water ground temperature.

The design has two couplings for the power and water sources. Though installing it looks easy, hiring a professional to do it is recommended by Lotus. You can call a licensed contractor to help decide on the location to install and make sure it functions perfectly and produces the needed quantity of hot water.

This water heater can’t produce as much water as needed in your home. You can only get water for washing dishes or prepare a meal. The hot water provided can only fill a sink. There is a power button on the front of the heater. To turn the heater off and on, you have to flip the switch. This helps to save more on energy usage as it doesn’t have to be run all day.

Though this Lotus model has a degree rise of forty-five degrees Fahrenheit, when installed with an aerator you will get the best result. This ensures that the flowing water gets to the desired maximum temperature. Its compact size makes it suitable for recreational apartments, boats and vehicles.


Bosch Electric Tankless Water Heater
Bosch Electric Tankless Water Heater
3.5 out of 5 stars
View on Amazon


  • Saves space, 5 pounds light weight, ultra-compact
  • Easy installation below kitchen or bathroom sink
  • 98% efficiency
  • 2kW output, 220V, 208V


If you are looking for a tankless water heater to supply your kitchen or bathroom sink, the Bosch Tronic 3000 is a perfect choice. With a low-temperature setting and flow rate, it may not work perfectly for laundry or taking long baths and showers. It can be used to supply quick hot water for dish washing, cleaning hands or other simple chores in your home, and can be installed with other heaters too.

Its easy installation is one of the reasons some people like it. With the instructions that come with it, you can easily install the Bosch Tronic 3000 without the help of a contractor. It has a compact size which makes it suitable for installing inside your bathroom cabinet or under the kitchen sink.

The Bosch Tronic 3000 is a perfect option for people who already have a smaller heater which can’t hot water to the whole house. It can produce hot water which is hot enough to kill germs and remove bacteria from the hands.

The Bosch Tronic 3000 tankless water heater can be used with either a 208V or 220V breaker. It weighs about 5 pounds, and can also. With a flow rate of 0.5 gallons per minute, it is great for hotels and offices which have private bathrooms but might not be the perfect deal for your household needs.


Eccotemp L5 Tankless Water Heater with EccoFlo Pump and Strainer
Eccotemp L5 Tankless Water Heater with EccoFlo Pump and Strainer
4.1 out of 5 stars
Not available
View on Amazon


  • Powered by liquid propane
  • 5 gallons per minute, 12V, 50 PSI, 13 pounds weight
  • Electricity not needed(Battery igniter)
  • Includes 6-inch stainless shower hose


Though the Ecootemp L5 portable tankless water heater is the cheapest on our list, it is a reliable outdoor water heater. Most other models need a gas or electric hook up inside the home and warn against using them outdoor. This Ecootemp model uses two dry cell batteries which can be safely used outdoors.

It has a light weight which makes it convenient to go with on vacation, camping or hiking. It can easily be connected to any large or small propane tank to get enough hot water for cleaning up or showering.

It has a regulator knob for the gas which allows you to adjust the flow of gas to either a minimum or maximum level. With this, you can enjoy cooler or hotter water as you desire. The knob can also be used for regulation of the water pressure.

Despite the small size of the Ecootemp L5 water heater, it still beats our imagination that it produces up to 1.4 gallons per minute. If more hot water is needed, you only have to use the water heater for a longer period.

It has a metal handle at the top which makes it easy to pick up the water heater and carry around conveniently. It comes with a shower nozzle which can be used for washing easily. Because of its smaller size and lower flow rate, it ranks this low on our list.

Buying Guide: choosing the best tankless water heater

When you have a tankless water heater, finding space to contain a newly bought water heater will be nothing to start worrying about. While looking at water heaters online, make sure you find and buy the best that suits you. When choosing the best, these factors are to be considered.


Traditional water heaters have space inside them to increase the water temperature. Tankless designs do not have tanks of water which is perfectly heated at one’s disposal. Its capacity should be put into consideration to make sure it can meet your family needs.

If your family does much laundry, daily meal and food preparation, and takes over three showers, only then will you need a water heater that has over 55 gallons capacity. Otherwise, a water heater which will heat less than fifty-five gallons daily should be suitable for you.


The rate of flow each minute which is usually listed in the features on the box should be considered too. The flow per minute refers to how much water the heater can heat up in a minute. Most designs can heat up to 3 or more gallons per minute; enough amount to take a shower or do dishes.


Heaters which have LCD or digital display are very easy to use. With the listed buttons on the front, changes can be made to the settings such as the water temperature being adjusted.


Although tankless heaters do not take up as much space as traditional models, the overall size still needs to be considered. Most designs are now built in compact shapes which are as small as average suitcases. This will reduce the stress that comes with installing them.


Having electric or gas system will determine which water heater is right for you. If you have an electric system and buy a gas water heater, installing it will require more cost. Making sure the water heater will work perfectly with your home energy system.


When taking a shower, the temperature of the water gets to about 105 degrees. Some people prefer taking hotter showers, and others enjoy cooler showers. Carefully examine the box to know the temperature limits of the heater.

ENERGY-efficiency ratings

This is not essential to all, but few people will consider the energy efficiency ratings. The energy efficiency rating is a measure of how efficient and effective the water heater is. Some water heaters come with very high ratings from Energy Star which can be seen at the front of the gadget.


Most times, tankless heaters do not produce as much hot water as traditional water heaters. Though, with the invention of recirculation technology which is found on few models, hot water will always be available.

The recirculation system brings in water and makes the water to circulate the coils which bring it to a perfect temperature. As the water flows over the hot coils, there’ll be enough water for all of your needs.


Buying the right water heater for your home depends on your overall demand for hot water, the cost of the product, and the climate in your environment. Having studied our buying guide and review on the best 10 products, you can now get to a nearby store and get the best tankless water heater of your choice. Good luck!