Best Tankless Water Heaters 2023 (Top 10 Picks)

Are you looking for the best tankless water heater? We tried multiple heaters from different companies to check the efficiency & energy costs for your best decision.

Tankless water heater saves up a lot of space and offers higher energy efficiency than conventional water heaters. Besides, it never runs out of warm water.

Since there is no storage tank, you can use it within the limitations. The basic unit is the GPM of hot water; think about peak activity periods and determine how many water fixtures might be

Best Tankless Water Heaters (Our Top Picks):

Let’s explore our top ten choices; our best picks will help you make the right decision. 



Power Source


Rinnai Indoor Tankless Hot Water Heater


Gas Powered

EcoSmart ECO 18



Bosch Tronic 3000


Corded Electric

Takagi T-H3-DV-N


Gas Powered

EcoSmart ECO 11



Rinnai V65IN


Gas Powered

Rheem 240V


Battery Powered

Rheem RTG-84DVP


Gas Powered

AO Smith ATI-310-P



Stiebel Eltron Tankless Water Heater


Battery Powered

1. Rinnai Indoor Tankless Hot Water Heater

The first on our list is a natural gas tankless water heater. This unit is an efficient way to get a ready-made hot water supply on demand.

Also, Rinnai is a famous brand; all of its products are pretty durable and effective. 

After trying and testing this product over time, we can ensure that this model combines value and efficiency. A faster flow rate is one of the best parts of the Rinnai Indoor Tankless water heater.

Compared to a conventional tank water heater, this unit is highly effective and won’t disappoint you when it comes to hot water.

This heater offers 7.5 GPM of hot water; that can support up to 5-6 fixtures simultaneously. However, it also depends upon the incoming groundwater temperature. 

The Rinnai heater can serve as a bonus if you live in a cold-weather climate; this unit can provide a water temperature of at least 57 degrees.

In addition to this, the Circ-logic recirculation technology optimizes the tank’s recirculation pump energy usage. 

Highlighting features:

  • This unit comes with a standard digital controller. 
  • The Circ-logic recirculation technology optimizes the energy 
  • It comes with an error code indicator. 
  • It can offer 82% thermal efficiency. 

The reviews for this heater are no surprise, considering the excellent features and the efficient heating mechanism.

Since it works in extreme cold, you can rely on this heater if you move to Alaska or further North! However, the thermal efficiency and the brand name make it a great pick for everyone. 


  • The flow rate is fast
  • The recirculation pump feature is an additional feature
  • Works well in all seasons


  • Requires maintenance by professional

Check Current Price and Rating on Amazon

2. EcoSmart ECO 18

Next on our list is EcoSmart tankless water heater. This heater is an electrical water heater, but it’s pretty affordable. Also, this unit heats more than 2.5 GPM and can easily support multiple showers at one time.

The incoming water temperature is 62 degrees Fahrenheit or more, so people living in the colder regions prefer buying this unit. 

Besides, this mode; offers electric operations, and it is pretty easy to install in a conventional tank water heater.

The overall design is aesthetic and does not take much of the space. But, in comparison to the Rinnai Indoor Tankless Water Heater, this model is limited in capacity. 

Highlighting features: 

  • This product is highly durable in terms of longevity. 
  • Easy installation and comes with a digital meter. 
  • The copper and stainless components prevent corrosion. 
  • It Saves up to 60% on the water heating costs. 
  • This unit is equipped with self-modulating technology.

EcoSmart is a good choice for home use as this heater can supply enough water for personal consumption. However, you must compare each heater before you buy.

Our comparison made this brand a clear topper and that is why we mentioned it before the others! 


  • Aesthetically smart heater
  • It comes with a digital meter
  • It is equipped with self-modulating technology


  • Frequent tripping of the heater

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3. Bosch Tronic 3000

There are countless benefits of buying a tankless water heater. The next on our list is the highly compact and highly-effIcient; Bosch Tronic 3000.

This unit is small enough to fit under the sinks easily. Moreover, this is one of the most recommended models for smaller houses and apartments. 

As compared to, ECOsmart; this model is indeed more productive. You can quickly get the water boost in your kitchens and bathrooms, and there will always be hot water available with this heater.

This product is indeed a hot seller with a 98% energy efficiency rating. 

This compact tankless heater has a 2.5 GPM and easily fits into a small place.

The stable features include quality and easy maintenance, and this product comes with a premium glass-lined material.

Besides, you do not need to hire an HVAC technician to install this model—Independent installation with a 120-volt outlet. 

Highlighting features:

  • 2.5 GPM with a thermal efficiency of 98%.
  • Fast recovery rate; supplies water to two sinks at one time. 
  • Easy installation; and mounting process. 
  • This unit prevents corrosion and abrasion from water.

Bosch enjoys fame and now we know why! This heater was a winner because of the compact size and convenient use in kitchens and bathrooms.

If you like to keep the electricity bill under control, (who doesn’t!) then this model is worth a second look! 


  • The rate of flow is commendable
  • The installation process is easy
  • It does not require maintenance


  • Corrosion is an issue

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4. Takagi T-H3-DV-N

Tankless water heaters work hard to capture the right amount of energy and improve efficiency. Takagi T-H3-DV-N; is not less than any conventional condensing water heater.

This unit can produce 10 GPM of hot water, and it can also supply water to up to four fixtures in the warm weather and three fixtures when the temperature is more relaxed. 

Compared to Bosch Tronic 3000 or Ecosmart, this unit saves more energy by capturing the heat from the exhaust produced using a secondary heat exchanger.

In addition to this, Takagi is an energy-star certified tankless water heater. Moreover, this is a 199,000 BTU tankless water heater by a Japanese company, and they are known for providing a reliable flow of water for showers and other household needs.

However, you will need a service technician to troubleshoot or repair this water heater. 

Highlighting features:

  • Endless consumption of hot water. 
  • Compact and space-saving model. 
  • The computerized system with no pilot light. 
  • This unit offers freezing, overheating, and surge protection. 

Japanese technology at its best, the Takagi tankless heater is an excellent way to enjoy lavish showers without paying exorbitantly.

The economy feature makes this sturdy and long-life heater an excellent choice. We found the Japanese technology easy, and the need for a technician was not for every user either.

In case anything does not work the way you wanted, you can turn for help, but the Takagi ensures that happens once in a blue moon. 


  • The water flow is reliable
  • It can supply water to up to 4 fixtures
  • The installation process is simple


  • Cleaning and maintenance is an issue

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5. EcoSmart ECO 11

Are you looking for a tankless water heater for a small home or apartment? Consider EcoSmart 11; this unit is perfect for a small family.

It is indeed a great option if you want to run 1-3 water fixtures simultaneously. For example, you can use two sinks and one shower at one time. 

However, if you compare this unit with Ecosmart eco 18, this unit has a limited capacity. This model can heat up to 2 GPM and produces a reasonable flow rate.

Even if you live in a colder climate, the incoming water temperature sinks below 72 degrees. Besides, this unit saves up to 60% on your water heating cost. 

The best part; you will never run out of hot water with this tankless water heating. With self-modulating technology and design, this unit is indeed recommended. 

Highlighting features:

  • This unit comes with a 60% water heating cost feature.
  • The self-modulating design and technology prevent insulation. 
  • With 2GPM, it produces a reasonable flow rate. 
  • Compact and space-saving design.

Now that there are two EcoSmart tankless heaters, you have a choice between convenience, and even more convenience.

While this list is not in perfect ranking, EcoSmart ECO 11 is cost-efficient but you may think the water heated per minute is less than the other models. However, for household use the amount of water is enough. 


  • It comes with a technology that prevents insulation.
  • It can supply water to up to 3 fixtures
  • This unit saves up to 60% on your water heating cost.


  • Installation is a task

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6. Rinnai V65IN

Next on our list is Rinnai V65IN; this unit is a superb appliance capable of simultaneously serving up to five different fixtures. However, the product can supply 6.5 gallons of heated water per minute during warm weather. 

This unit is slow if we compare this model to our previously listed Rinnai Indoor Tankless water heater. It comes with a handy feature of automatic shutdown; that cuts down the risk of overheating and damage caused by mineral deposits.

We are highly satisfied by this product’s overall structure as it has a robust construction that prevents corrosion and abrasion. 

Highlighting features:

  • This unit offers up to a 6.5GPM hot water flow rate. 
  • You can control it through mobile app features. 
  • Automatic system vacation mode.
  • Buyers can use it for residential and factory purposes. 

Rinnai V65IN is reliable and we found this heater more convenient than others due to the mobile app feature, which makes it easier to control the heating process even when you are not near. 


  • It can supply water to up to 5 fixtures
  • It prevents corrosion and abrasion.
  • It can be used for commercial purposes as well


  • It requires a special vent system for condensation reasons

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7. Rheem 240V

Rheem 240V is one of our most favorite tankless water heaters on our list. It is indeed one of the impressive units with a 99% efficiency rate.

We had a perfect time trying this product as it can be an excellent choice for smaller households. 

Usually, many people are concerned about buying a tankless water heater for small families as they are worried about the BTU.

Rheem 240V has a maximum BTU of 45,000 and comes with a 4 GPM max flow rate. However, it is not a good choice; if you have more than three people. Also, if you are a fan of aesthetics, this model can be an excellent option. 

In addition to this, it comes with external adjustable digital thermostat control with an LED display. Self-modulating power control and easy installation are two good features. 

Highlighting features:

  • This unit offers 99% energy efficiency. 
  • Provides External control to adjust the temperatures in increments. 
  • It provides easy replacement and simple installation. 
  • This unit has durable copper immersion and two heating elements. 

By now you can easily see why this heater made it to our list. The tankless heater is an excellent product, and Rheem has added features that make it an economical choice. 


  • It comes with a 4 GPM max flow rate.
  • It is equipped with Self-modulating power control
  • It has two heating elements.


  • Maintenance is an issue

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8. Rheem RTG-84DVP

Next on our list is Rheem RTG-84DVP; this is a high-efficient appliance designed for all kinds of rural and suburban homes running on gas.

Also, this unit extracts every ounce of heat energy by using a secondary heat exchange component that pulls the heat out of the exhaust. 

In simpler words, this product is more of a condensing appliance. This tankless heater can provide up to 8.4 GPM; of heated water per minute.

This product offers a .40 minimum activation flow rate along with 180,000 BTU. In addition to this, it comes with a remote control and 10 feet of thermostat wire. 

Besides, this is more of an eco-friendly product as it meets low nitrogen oxide emission standards. 

Highlighting features:

  • Maximum flow rate .40GPM. 
  • This unit comes with a remote control and 10 feet of thermostat wire. 
  • An environment-friendly, space-saving tankless water heater. 
  • The heater includes a UMC 117 remote control. 

With a high GPM the Rheem RTG takes the lead but what made this heater shine out for us was that it is environment-friendly. You can take a second look at this heater and it will only impress you more!


  • It comes with a remote control
  • The flow rate is fast
  • The installation process is easy


  • Corrosion is an issue

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9. AO Smith ATI-310-P

Well, this unit in our list is an exceptional case. This heater is perfect for smaller houses as well as travelers. Consider yourself having the time of your life on a lake, but you cannot take a good shower. 

This unit is the 38-pound tankless water heater that delivers nearly nine gallons per minute. Yes, 9 GPM; do not go on the size, as this unit outperforms others.

Moreover, this unit works in the suburbs too. You need to install this unit outside or on a hidden back or maybe on a sidewall.

This model can supply water to two fixtures at the same time. You can use the remote control to adjust the temperature. 

Highlighting features:

  • This unit comes with built-in freeze protection. 
  • This unit offers an Inlet and outlet thermostat for constant monitoring of temperature.
  • Manual reset limit. 
  • Automatic shutdown on overheating. 

The travelfast tankless heater makes it possible for users to enjoy a safe and warm bath anywhere they land!

The compact and easy-to-carry heater is a must-buy for those who travel and have experienced a shock when the power fails in public accommodations!

For your safety and peace of mind, the AO Smith is a good choice!


  • It works well in the suburbs too
  • It comes with a remote control
  • It has built-in freeze protection


  • Maintenance is an issue

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10. Stiebel Eltron Tankless Water Heater

The last on our list is the Stiebel Eltron Tankless Water heater. This heater is from a German manufacturer and the best and most renowned product of Stibel Eltron.

Moreover, this unit comes with a GPM of 4.0; it is considered one of the most decent electric instantaneous water heaters. 

However, this model is suitable for a small home only. Besides, this model can only provide water to two fixtures simultaneously.

However, the EF rating is pretty good; highly-reasonable heat with 99% energy efficiency. The advanced flow control patented technology automatically maintains the temperature of the water for ultimate comfort. 

The sleek and small design saves up a lot of space yet provides endless water. Besides, the electronic switch activates the hot water, and it’s easy on the ears too. 

Highlighting features:

  • A continuous flow of water with optimal temperature.
  • Sleek and space-saving design. 
  • Easy operation and simple installation. 
  • Noise-free operations; and comes with a digital temperature display. 

Stiebel Elton is a popular name when it comes to tankless heaters, and it is all due to this model!

Following positive user reviews, you can give this compact tankless heater a try and we are quite sure there will be no disappointments! 


  • The EF rating is pretty good
  • The installation process is simple
  • It comes with a digital temperature display


  • High-maintenance heater

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What to Consider When Buying a Tankless Water Heater?

Reduced energy consumption and immediate access to hot water all day long, counting just a few benefits of buying a tankless water heater.

However, to choose tankless water, keep the following factors in mind. 

Fuel Type: There are three main fuel types for a tankless water heater: natural gas, propane, and electricity. The power of electrical models is less than the of gas models. However, installing an electrical heater is more accessible than the gas one. 

Flow rate: GPM (Gallon per minute) is the maximum volume of hot water that the tank can produce. Flow rate is measured in gallons per minute with each fixture.

A tub uses 4GPM, and a shower uses 3 GPM. Therefore, you need to decide to depend upon the persons and size of your family. 

Power Input (BTU): A British thermal unit (BTU) measures the energy required to heat water to a targeted temperature is measured in a British thermal unit (BTU). The more the BTU, the more the rising temperature.

Size: You have to choose the size of tankless water heater to get the maximum benefits. If you have hot tubs at your place or other such usage of water, then the heater with larger capacity will be required.

Well, we hope that this article will help you make the right choice. However, we would recommend you to go through the other options and factors to consider while making a choice. 

How we tested the tankless water heater?

Before buying any appliance, it is important to do your research. I read many tankless water heater reviews online and consulted with experts to find the best models on the market. After much deliberation, that is how I tested the tankless water heater.

Fuel Type

One of my friends recommended buying a tankless water heater, so I researched it before making my purchase. I learned that these heaters have three main fuel types: natural gas, propane, and electricity. I ultimately chose an electric model because it seemed like the most efficient option for my home.

However, I used to have a gas model in my old home, and it worked well too. Electric-powered heaters are becoming increasingly popular, so I would try one. They are very efficient and do not require any ventilation.

Hybrids also use gas and electricity, but I did not explore this option in depth. From what I understand, these heaters are a bit more expensive and may not be as efficient as electric models.

EF Rating & Durability

I checked the EF ratings of the tankless water heaters because  I wanted to know which would be the most efficient. I also looked at the durability of each tankless water heater.

I figured that the more durable the tankless water heater, the longer it would last. Most importantly, my mother already had a tankless water heater, which lasted for over ten years, so I knew tankless water heaters could be durable.

Tankless water heaters are more energy efficient than traditional tank-style heaters because they only heat water when needed. This can save you money on your energy bill over time.

The first thing I looked at when choosing a tankless water heater was the EF rating. This is because the EF rating measures the efficiency of a given appliance. The higher the EF rating, the more efficient an appliance is. I wanted to choose the most efficient tankless water heater because I wanted to save money on my energy bill.

Flow Rate Capability

To find the best tankless water heater, I looked at the maximum flow rate that each model could handle. This is an important metric because it tells you how much hot water the unit can deliver at once.

One of my colleagues told me to check the flow rate capability. If you have a large household with multiple bathrooms and appliances that use hot water, you’ll want a tankless water heater with a high flow rate.

Tankless water heaters come in various capacities that determine the maximum flow rate of hot water they can deliver. Smaller units have lower flow rates, meaning they can’t supply as much hot water as larger models.

I was told to find the capacity by this method. To find the best tankless water heater for your needs, calculate the maximum flow rate your household will demand at any given time. To do this, add up the flow rates of all the fixtures in your home that will be using hot water at the same time.

For example, if you have a shower with a flow rate of 2 gallons per minute (GPM) and a sink with a flow rate of 1 GPM, the maximum flow rate your household will demand is 3 GPM.

Once you know your maximum flow rate, consult a sizing guide or calculator to find the right tankless water heater.

I found that the average flow rate for tankless water heaters was about 3 gallons per minute (GPM). However, some models could handle up to 8 GPM or more.

Drain Valves:

Most tankless water heaters available in the market come with a drain valve. Drain valves are generally located at the bottom of the unit. They help drain out all the unit’s water for maintenance and cleaning purposes. My mother told me to check the drain valves, which is an extremely convenient feature.


Is tankless water heater efficient?

Yes, tankless water heaters are much more efficient than traditional storage tank water heaters. They heat water on demand, so you’re not wasting energy keeping a tank of water hot all the time. Tankless water heaters can save you up to 50% on your water heating costs.

What size tankless water heater do I need for a family of 2?

A tankless water heater will be able to provide hot water for a family of two, as long as the total flow rate of all the fixtures in the house does not exceed the maximum flow rate of the water heater.

Depending on the model, tankless water heaters typically have a maximum flow rate between 4 and 8 gallons per minute. Additionally, it is important to consider the peak hot water demand when sizing a tankless water heater. The peak hot water demand is the maximum amount of hot water that will be used at any one time.

For a family of two, the peak hot water demand is typically between 10 and 15 gallons per minute. Therefore, it is recommended to select a tankless water heater with a flow rate that meets or exceeds the peak hot water demand.

Is there a chance of growing bacteria in a tankless water heater?

It is possible for bacteria to grow in a tankless water heater, but the chances are much lower than if you had a traditional water heater. This is because tankless water heaters do not have standing water that can become stagnant and provide an ideal environment for bacteria to grow. Additionally, tankless water heaters typically have built-in filters that help to remove impurities from the water before it enters the unit, further reducing the chances of bacteria growth.

Is it difficult to maintain a tankless water heater?

It is not difficult to maintain a tankless water heater. You will need to regularly flush the unit to remove any sediments that may have accumulated. You should also descale the unit every few months to prevent mineral buildup. Other than that, you will just need to keep an eye on the filters and perform routine maintenance according to the manufacturer’s instructions.

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