10+ Best Tankless Water Heater Reviews 2021– [Buyer’s Guide]

Over the last decade, the popularity of tankless water heaters have skyrocketed and for all the right reasons. One of the biggest reasons behind the growing popularity of tankless water heaters is the benefits associated with it. Tankless water heaters are any day better and more advanced than the traditional water heaters.

With the help of a tankless water heater, you no longer have to waste your time waiting for the water to get heated. For big families with more than 4 members, a tankless water heater serves to be the best option. These water heaters are designed to provide on-demand hot water. Not just that, but a tankless water heater is also loaded with several useful features which makes it more convenient to use it.

Another big reason why you should switch to tankless water heaters is that they are more durable and long lasting. Most of these water heaters are backed by a long warranty period of 5 years or more. Some of the models even come with a lifetime warranty.

Now if you are thinking of switching to a tankless water heater, you are at the right place. Since there are numerous water heater companies manufacturing quality products, it may get difficult for you to choose the best one. To make things easy for you, we have listed 12 best tankless water heaters 2021 to choose from.

Go through the best tankless water heater reviews given below and you will get an idea about the products that are worth investing in. For your convenience, we have also added a tankless water heater buyer’s guide in one of the initial sections below.

Buyer’s Guide

Size:

Gas Vs Electric:

Energy star ratings:

Installation:

The next important conization is the installation process. Although most of the water heaters can be installed easily, however, there are certain models that may require professional help. Before, making your purchase, check out with the manufacturer whether the unit requires professional installation or not. Having to hire a professional in order to install the unit means you have to spend extra money. This is why it is suggested that you go for a water heater model that can be installed easily without any professional help.

Rate of flow:

This is yet another important feature that you need to look into. When you visit a store to buy a water heater, you will notice the term GPM everywhere. GPM means Gallons Per Minute. GPA indicates the amount of hot water the unit can supply.

Durability:

Ratings:

When it comes to buying a tankless water heater, you should also check the ratings it has received by the other buyers. You should also check the reviews given by other users so that you get a good idea about the product. This will help you to decide whether the product is worth investing or not. You should avoid investing in a product with low ratings.

Additional features:

If you want to buy the best tankless water heater, you should also check for additional features. Like for example, Wi-Fi control and remote control. These are some of the extra features that you can get with some water heaters. Other than that many of the models also provide you with a lot of free accessories as well. Before, buying a water heater you should check the number of features and accessories that you are getting along with the product. However, it’s obvious that the more the number of features, the higher the price of the water heater. So if you are willing to spend a little extra cash, you can enjoy some of the best features in a tankless water heater.

Budget:

Best Tankless Water Heater Reviews 2021

Now that you already know how to buy the best tankless water heater, it’s time that we move on to our best tankless water heaters reviews. We have shortlisted some of the best tankless water heaters for you to choose from. You can find products in all ranges and sizes. You can go through the details of each of the products and choose the ones that best suits your need. Here you go with the list.

#1 Atmor Electric Water Heater:

On the first spot, we have the Atmor Electric Water Heater which is tagged as the best tankless water heater in 2021. The product has received high ratings from the buyers which clearly shows how happy the customers are with the product. This tankless water heater is ideal for users who do not have access to liquid natural gas or propane. In that case, you can make good use of this tankless water heater. The best thing about this tankless water heater is that you can get an unlimited supply of hot water instantly. With this product at your disposal, you never have to go without hot water. Also, you don’t have to waste your time for the boiler to start. This tankless water heater is designed to provide you with instant access to hot water whenever you want. The energy saving design of the product allows it to save a lot of energy. It is equipped with an advanced thermo-pro self-modulating system which allows the product to control the amount of energy it consumes to boil the water. This very feature helps the product to save maximum energy and thus, making it energy efficient. Not just the features but even the construction of the water heater is worth mentioning. The interior of the water heater is crafted with high-quality stainless steel which makes the product more durable. It is corrosion resistant as well. If you have space issues, you wouldn’t find a chance to complain about this water heater. The compact design of the product makes it easier for you to store it even when you have less space availabl. Also, the product doesn’t need venting. The water heater is great for installing in a garage or home. It has a capacity of 3.7 GPM which is good enough to supply 3 taps simultaneously. The water heater also comes with digital controls which are quite easy to use. The product is also IP54 certified as it is a splash-proof product. This means you can install the water heater even in your bathroom. You will also be provided with a 2 year warranty period on parts along with 7-year warranty against leakage. Considering all the given features of the product, it is safe to say that this is the best tankless water heater in the market. With this tankless water heater at home, you will never have to run without hot water ever.

#2 Rheem RTEX-13 Tankless Water Heater:

If you are in search of an affordable tankless water heater Rheem RTEX-13 water heater is the classic example. The high ratings of the product clearly indicate that this is the best tankless water heater in the market. Buyers who have already used the product are quite satisfied with its performance. The water heater can be easily installed without much effort. Not just that, but replacing the old parts of the product is also quite easy because of its construction. The water heater also comes with a LED screen where you can read the current water temperature and can also adjust it by 1 degree Fahrenheit accuracy. What makes the water heater great is the self-modulating feature which allows it to control the total amount of energy consumed. With the use of this water heater, you can save regularly on your electric bills. The water heater is made with high-quality steel which makes it extremely durable. Both the heating elements are constructed of copper which makes it field serviceable and long lasting. The product has a high energy efficiency of up to 99.8%. In addition, it also comes with easy to use external controls. The water heater is designed to provide you with 1.5 gallons of flow rate in every minute. This is enough to supply 2 taps at once. To make the installation process of the water heater easy, it comes with a 3 feet long electric cable, side ½ inch compression water connections and ½ NPT adapters. The product is also lightweight which makes it more easier to install it in your house. The product comes with a 1 year warranty period for parts. Other than that, you will also get a 5-year warranty on the heater chamber as well. This water heater is not only affordable but it also provides you with excellent performance which makes it one of the best tankless water heaters 2021.

#3 Stiebel Eltron Tempra Plus 36 Electric Water Heater:

Made in Germany, Stiebel Eltron Tempra Plus 36 Electric Water Heater makes the ideal choice for your home. The compact design of the product makes it easy to install. Also, it doesn’t require venting. With this tankless water heater, you are assured to get plenty of benefits. One of the good things about the water heater is that it runs silently. This means you don’t have to tolerate the annoying noises of a water heater. Not just that, but the product is also designed to provide you with instant hot water access. Stiebel Eltron has over 90 years of experience in manufacturing water heaters. They know what is best for their customers. With this water heater, there is no need for you to waste your time for hot water. What buyers love about this product, is that it can automatically adjust the temperature of the water when the demand for hot water increases. There are no fluctuations at all. Not many tankless water heaters in the market comes with such features. The water heater is also equipped with the self-modulating technology which makes the product 99% energy efficient. With the use of this product, you are sure to save a lot on your monthly electric bills. This water heater is considered to be the best tankless water heater in the market. The product can provide you with both reliability and comfort. With this product, you can get a flow rate of around 0.77 gallons per minute. You can adjust the desired water temperature with the easy to use digital controls. In addition, you also get a 3-year warranty along with a 7-year warranty on leakage. This is by far one of the best tankless water heaters 2021 with all the right features that you need.

#4 Ecosmart ECO 27 Electric Tankless Water Heater:

The next on the list we have is the Ecosmart ECO 27 Electric Tankless Water Heater which has received high ratings on Amazon. It has been reviewed by about 2000 people and they are all happy with the performance of this best tankless water heater. The product is mainly known for its efficiency and quality. This is the Editor’s Choice tankless water heater that is designed to provide you with excellent performance. It is guaranteed that you won’t regret getting this product home. It is meant for everyone who is looking for an efficient electric water heater. With this water heater at home, you’ll never have to run out of hot water ever again. The product comes with a digital control unit which allows you to adjust the temperature according to your preference. With the help of this feature, you can set the ideal temperature for your family. The small size of the product also makes it easy to install. If you have less space in your house, you can surely consider going for this product. It can save 12 cubic feet of total space. Other than being efficient, the product also comes with stylish looks. It has got a pleasing design for a water heater. It is constructed with high-quality stainless steel and copper which adds to its reliability andd durability. Not just that, but you can even replace the old parts of the product easily. The water heater has been designed to save maximum energy. It can save up to 50% on your electricity bills. So if you want to cut down on your monthly energy expenses, you already know which water heater model you should opt for. The water heater can provide you with 6 gallons of hot water per minute which is enough to supply 3 taps at once. Considering the capacity of the water heater, it can be considered as an ideal product for large families. The water heater has a high capacity to supply 4 taps and a sink at once. The water heater is also equipped with the self-modulating technology which allows the product to save more energy. The list of benefits doesn’t end here. The water heater also comes with a lifetime warranty. This is one of the major benefits of getting this product. If you are looking for the best tankless water heater, look no further as you have got Ecosmart ECO 27 Electric Tankless Water Heater. This is the best that you can get and that too at an affordable rate.

#5 Stiebel Eltron Tempra 24 Plus Electric Tankless Water Heater:

Stiebel Eltron Tempra 24 Plus Electric Tankless Water Heater is one of the highly rated products currently available on the market. It has a huge base of satisfied customers who are just more than happy to use this product. The water heater may be small in size but it is definitely not small in its performance. This lightweight water heater is designed to provide you with everything that you need in a high-quality tankless water heater. The compact size of the water heater makes it ideal for small houses and families. The product is just the size of a briefcase. Stiebel is one of the well-known German companies that have been providing a-grade quality water heaters to its customers. Each of their products is worth praising and this one is no exception. The German build quality of the product makes it the best tankless water heater in the market. The best thing about the water heater is that it doesn’t produce much noise. The silent operation of the product makes it more convenient to use. Also, the product doesn’t need any venting at all. The main benefit of using this machine is that it is energy efficient. With the use of this product, you can save a lot of money on your energy bills. The water heater is designed to turn on only when you turn the power on. This allows the product to save maximum energy. The water heater is loaded with all the unique features that you could have asked for. When you have a high demand of hot water, the product will automatically adjust the temperature of the water to supply you with warm water. This is achieved with the help of advanced flow control technology. Just like the rest of the water heaters on the list, even this one comes with the self-modulating technology which enables the product to save around 99% of the energy. The product also provides you with 0.5 GMP of flow rate which is quite good. You also get a 3-year warranty that covers the parts of the water heater. Also, the product provides you with a 7-year long warranty on leakage. The offers you get with the product are unbelievably good. In addition, you can also mount the product easily on the wall. This is possible because of the lightweight of the machine. There is no denying that this is one of the best tankless water heaters 2021.

#6 Eccotemp FVI-12 Electric Tankless Water Heater:

Eccotemp FVI-12 Electric Tankless Water Heater is a complete value for your money. This budget-friendly tankless water heater is equipped with all the right features that you need. Despite its low price, the product provides with great performance. It is powered by liquid propane and requires a steady propane fuel source to provide you with hot water supply. This water heater is best suited for small houses with two or less numb of bathrooms. With this water heater, you get 3.5 gallons of flow rate per minute. The product is designed to be energy efficient. The best thing about the water heater is that it will switch on only when you activate it. This allows the water heater to save maximum energy. The lightweight of the product also makes it easier for you to install it safely. This product is ideal for small cabins and houses with less available space. This means that you don’t have to worry about managing your space to store the product. The product also comes with a UL power cord which can be connected to an outlet of 120V. This helps in the safe electronic ignition system to heat the water heater. Also, the product comes with an easy to use temperature controls that allow you to easily adjust the temperature according to your need. The product can be easily installed without any fuss. All you need is a fuel source and water to connect the ½ inch NPT. You will also get a digital thermostat for free. not just that, but you will also be provided with a manual water controller, safety till switch, stainless steel horizontal vent kit, hose, gas regulator and many other accessories. You can get all of these for free which makes it a valuable purchase. The product also comes with a 2 year warranty period if you order it from Amazon. All the features together make this product the best tankless water heater.

#7 Takagi T-K4-OS-NG Tankless Water Heater:

For a change, if you are in search of the best natural gas tankless water heater, you can surely go for the high-quality Takagi T-K4-OS-NG Tankless Water Heater. The product has been designed to provide you with high performance at all times. With the use of this product, you can get an unlimited supply of hot water whenever you want. The best part is that you can use this water heater in hydroponic systems, storage tanks, domestic applications, radiant floor systems, and recirculation systems. Considering the efficiency of the product, it can be said that this is the best you can get. The product is also backed by a 15 year long warranty period on the heat exchanger. In addition, you also get a 5-year warranty that covers residential use. This clearly indicates the quality and the confidence of the manufacturer on the product. Unlike, other tankless water heaters, this one can be controlled with remote control. This will make it even easier for you to use and operate the product. The product also doesn’t require any venting. This is an outdoor unit which is mainly known for its efficiency. The product has a power rating of 190,000 BTU which enables the product to deliver 8 gallons of non-stop hot water every minute. This is one of the biggest reasons behind the popularity of the product in the market. Not just that, but the product also has a high flow rate which enables the water heater to supply hot water to more than 2 bathrooms simultaneously. The product is also equipped with outlet and inlet thermistors which allows you to continuously keep a check on the water temperature. The compact size of the product makes it lightweight. This, as a result, makes it more convenient for you to use it. The product comes with a 0.82 energy factor which adds to the efficiency of the water heater. In addition, the product is also environmental friendly. One of the biggest benefits of using this water heater is that it is money saving. It runs on natural gas and works only when hot water is needed. This enables the water heater to save around 45% of total energy consumption. This means that you can save a good amount of money with the help of this water heater. The product also comes with a number of safety features including overheat protections, freeze protection, and surge protection. It includes the troubleshooting diagnostic codes as well. All these features together contribute to the greatness of the product. This product is ideal for the ones who are in search of a good and reliable outdoor water heater. With loads of safety features, this product serves to be the best option for you. Overall, it can be concluded that this is the best tankless water heater currently available on the market.

#8 Rinnai RUR98IN Ultra Series Natural Gas Tankless Water Heater:

Rinnai RUR98IN Ultra Series Natural Gas Tankless Water Heater is yet another great tankless water heater that you can consider buying. This is a high-end water heater with all the important features that you need. This water heater is ideal for the ones who are looking for an indoor tankless water heater. The product provides you with a high GPM rate. The water heater is designed to provide you with 9.8 gallons of hot water on demand. This is enough water to supply 3 to 4 taps at once. If you have a big family with more than 4 to 5 family members, this particular model will serve to be the best choice for you. This model can also be used for flats as well. However, the water temperature may fluctuate depending on the area you live in. In case, you reside in a very cold area, the temperature of the water may drop a bit. The recirculation capability of the product allows the water heater to supply an unlimited amount of hot water even if there is no dedicated recirculation line. This is one of the best features of the product because of which it is so popular among the buyers. The water heater is designed to be installed indoors and comes with a tankless rack system. This is made compatible with ½ inch natural gas lines. The water heater requires venting for which you can opt for PVC type venting. One of the best features of the water heater is its patented condensing technology which gives the product a 0.96 energy factor rating. Other than that, the product is also equipped with dual exchangers which are known to make the water heater more efficient. This massive indoor tankless water heater is ideal for big families with multiple bathrooms. The product is designed to provide you with maximum efficiency. With 9.8 GPM of flow rate, this is the best tankless water heater on the market.

#9 Rheem RTG-84XLN Natural Gas Tankless Water Heater:

Rheem RTG-84XLN Natural Gas Tankless Water Heater is one of the best outdoor tankless water heaters you can get in the market. With 4.5 stars rating on Amazon, this water heater serves to be as one of the best options. The product has been designed to provide you with 8.4 gallons of hot water every minute. This is more than enough to supply 3 bathrooms at the same time. The high capacity of the water heater makes it ideal for big families. In fact, this is one of the highest volume water heaters available out there. With the help of this product, you can get an unlimited supply of hot water all day long. The product comes with a UMC-117 remote control for free. Using the remote, you can easily control the water heater. This makes it more convenient for you to operate the product. You also get a 10 feet thermostat wire with your purchase. Adjusting the water temperature becomes quite easy with the remote control. One of the best features of the product is the LOW NOx variant. This makes the product eco-friendly in nature. The compact size of the product makes it easier for you to store the product. In case, you have less space, you can definitely go for this product. You can even mount the product easily on your garage wall or at any available outdoor space. The product has a BTU rating of 11,000 to 180,000 max. The product is also equipped with the next generation burner technology. This enables the water heater to be energy efficient and thus, you can save money on energy bills. In addition, you also get a 12 year long warranty period along with the product. This product is best suited for people who are looking for a tankless water heater powered by natural gas. Considering all the given features, this is undoubtedly the best tankless water heater available in the market.

#10. Rheem RTG-95DVLN & RTGH- 95XLN Tankless Water Heater:

Rheem RTG-95DVLN & RTGH- 95XLN Tankless Water Heater is yet another great natural gas water heater available in the market. With 4.3 stars rating on Amazon, the product is one of the most popular ones. People who have already used the product are more than just satisfied with the performance of the water heater. With all its features, this particular model is no less than the other tankless water heaters on the list. It has a 0.96 energy factor rating. With the use of this water heater, you can save loads of money on your energy bills. One of the highlighted features of the product is its water-saving activation technology. With the help of this feature, you can save around 1,100 gallons of water every year. This is achieved by reducing the flow rate in the water pipes until the set temperature is reached. This is one of the fewest water heaters that is equipped with a low flow activation technology. This enables the water heater to provide you hot water even when the demand is high. The product also comes with a recirculation pump kit. This speeds up the water circulation before it gets cold. As a result, it is able to save around 12,000 gallons of hot water per year. With this water heater at your disposal, you’ll never have to face cold water bursts. With the help of the ECONET smartphone application, you can easily control the water heater. All you need to do is connect ECONET accessory kit to the product and you are all set. The product also provides you with 9.5 GPM of flow rate which is quite good. If you want to increase the hot water flow rate, all you need to do is connect an additional unit with the water heater. The product is also backed by a 12 year warranty period that covers all the parts of the water heater. In short, this is one of the quality tankless water heaters available out there. It is ideal for serving 5 to 8 rooms easily. Loaded with all the latest features, this is the best tankless water heater out there.

#11 Eccotemp L10 Outdoor Tankless Water Heater:

On the second last spot, we have the Eccotemp L10 Outdoor Tankless Water Heater which can be a perfect choice for you. This outdoor tankless water heater has received quite a lot of good reviews from the buyers. The water heater is powered by propane. The water heaters is lightweight and weighs only 27 pounds. This is one of the smallest water heaters available in the market. The company Eccotemp has been manufacturing water heaters since 2004 and it surely knows how to keep its buyers happy. The product comes with a removable weather resistant cap on the top. Not just that, but you also get many other features including a manual temperature controlling knobs along with one adjustable water pressure gauge. The best thing about this model is that it can be used anywhere you want. All you need is a propane tank in order to power the water heater. A 20 pounds propane tank is enough for the water heater. The liquid propane is heated with two D cell batteries. You can also connect the water heater with any standard hose you want and it will work. This is possible because of its low-pressure activation technology which is only of 20 PS. One of the best features of the product is the auto shutoff. The water heater will automatically shut off after 20 minutes of continuous operation. It will also shut down automatically if you tilt the water heater beyond 45 degrees. This particular feature is provided to ensure your safety. The product has also been tested on 5,500 feet elevation and the product works perfectly fine. With the help of this water heater, you can get a 2.6 GPM flow rate of hot water. Not just that, but the product is also easy to install. It comes with a shower compatible design which makes it ideal choice for camping. The product is backed by 1 year of warranty. After going through the review of the product, it can be stated that this is the best water heater for RVs and campers. If you are looking for a portable tankless water heater, you can surely count on this one. This product is not only efficient but also a reliable one.

#12 Takagi T-KJR2-IN-NG Natural Gas Tankless Water Heater:

Takagi T-KJR2-IN-NG Natural Gas Tankless Water Heater is one of the best tankless water heaters available out there. Before you invest in this particular model, you should know that the product has received high ratings on Amazon. Buyers who have already used the product are happy with its performance. This should give you an idea about the efficiency of the product. The product comes with a 140,000 BTU power which allows the water heater to provide you with 6.6 gallons of hot water every minute. The water heater is good enough to supply water to 2 sinks and 3 bathrooms at once. For a big family, this is an ideal choice. However, you need to call for professional help in order to get the product installed. That’s because the product requires a 4 inch III stainless steel venting. Other than that, the product is just fine. The best thing about this product is that you can use it both indoors and outdoors. Originally, the water heater has been designed to be used on the indoors but you can easily transform it into an outdoor unit as well. The main advantage of using this product is that it is cost effective. Not just that, but the product is environment-friendly as well. With this water heater, you can get a .82 energy factor. This allows the water heater to save a lot of energy. As a result, you will be able to cut down on your monthly energy bills as well. This is one of the smallest water heater units from Takagi. The compact size of the product makes it lightweight and is thus comfortable to use. This product is best suited for small apartments and homes. You also get a lot of free accessories with your purchase. For example, you will get a set of inlet and outlet thermistors which will help you to keep a continuous check on the temperature. After reviewing all the features of the product, it can be concluded that this is an ideal water heater for small families. If you are looking for the best natural gas tankless water heater, you can surely opt for this one.

Conclusion:

After going through the best tankless water heaters reviews, hope you now have a good idea about all the best tankless water heaters available on the market. The list contains water heaters of all ranges and sizes. You can make your selection based on your requirement. You can also check out other models based on the factors mentioned and find a tankless water heater that best suits your need.