The Best Tankless Water Heater in 2021

Swapping out a traditional water heater for a smaller, more efficient tankless system is becoming increasingly popular. Homeowners are saying goodbye to those bulky, energy-hogging devices in place of sleeker, more modern models that feature no tanks. There is a slew of benefits that come from owning a tankless water heater in 2021, and if you’re looking to switch to the best products, we have you covered with the top 8.

First Here’s How We’ve Determined the Best tankless water heater

We searched high and low to find the best tankless water heaters in the market. These tankless water heaters were looked at to see how much hot water they are capable of producing as well as how much space they take up. We also looked into other features and other important bits of information while making our decision, such as price, type (gas or electric), and what people had to say about the device.

#1: Stiebel Eltron Tankless Heater Tempra Plus (Best Value)

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When it came to finding the best value in tankless water heaters, the only way to go was the Stiebel Eltron Tankless Heater Tempra Plus. This is all because the Tempra Plus combines state-of-the-art technology and precision with a price tag that can suit most individuals. It’s the biggest bang for your buck.

There’s a lot to love when it comes to the Stiebel Eltron Tankless Heater Tempra Plus. Known as the “World Leader in Hot Water Technology”, customers can feel confident purchasing from this company. They have also been in the tankless water heater “biz” for over 90 years now, which automatically sets them apart from the competition. 

One thing any homeowner will enjoy with the Tempra Plus is that it runs completely silently. This is a big change for some people who originally had larger, outdated equipment that could be heard from a mile away. Being small and compact with no venting required, it can fit in almost any home, anywhere, with ease. Plus it has a modern and sleek design that is aesthetically appealing.

The major bonus of owning Tempra Plus is that you will never have to worry about running out of hot water. That’s right – whether you spend 10 minutes or 2 hours in the shower, you can feel confident that you won’t run out of that much-needed hot water. This makes it a cinch to relax and enjoy, even when others are showering at the same time.

Another major bonus of the Tankless Heater Tempra Plus is that itprovides constant energy savings. Since the design is entirely tankless, you don’t have to worry about paying for standby losses that are found in traditional water heater systems. It’s known for being 99% energy efficient, which saves on bills, while the intelligent self-modulating technology works to save as much energy as possible.

The Tempra Plus is the second edition of the Tempera model, new-and-improved, and loaded with additional features and bonuses. And while the original model may have been a top-of-the-line choice for any homeowner, the newer model combines tried-and-true features with a slew of additional benefits including:

  • Keeping temperature consistent and constant thanks to an Advanced Flow Control. (New)
  • A handy digital temperature display that can be adjusted with ease. (New)
  • Designed with solid copper heating chambers to hold in heat better than ever before.
  • Providing continuous hot water to the user. 
  • Offering 240 Volt or 208 Volt.

There is a reason why customers are saying “Electric bill didn’t increase. 3 hot showers at once! Excellent!” and “Still running strong after 3 years” – it’s a product that works. For the greatest value in tankless water heaters, look no further than the Stiebel Eltron Tankless Heater Tempra Plus.

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#2: Rinnai RU 199iP Sensei Super High-Efficiency Tankless Water Heater (Best Tankless Water Heater)

If you are willing to spend a bit more money on a unit, then we highly recommend the Rinnai RU 199iP Sensei Super High-Efficiency Water Heater. Yes, this unit has a heftier price tag at $1,666.50; however, you have the option of monthly installments instead and free shipping is always included. Aside from that, any owner of this product will tell you that it’s worth every penny. And here’s why.

First and foremost, we should mention that the RU199iP Sensei SE is a unit that uses propane. With that in mind, it makes the top of the list for best tankless gas water heaters, but it also ranks highly against electrical models, too. With all of its added features and advantages, it quickly overshadows any unit – whether it’s an electric unit or a water heater tankless gas unit. As it is propane, it’s important to note that this particular model can only be installed indoors.

Secondly, the RU199iP Sensei SE is known for providing hot water continuously for the whole house. Even when it seems like everything in the whole house is turned on, this tank has the energy-efficient capabilities to provide the whole house with an endless supply of water with the perfect temperature. That being said, if you need water with the right temperature and you need it now, the RU199iP Sensei SE has you covered thanks to the superior water heating technology.

Reason #1 to Choose This Product: Superior Flow Rate

When it comes to opting for a tankless unit, one thing to never overlook is the flow rates. Almost every unit has a flow rate between 4 and 8 gallons per minute, but the RU199iP Sensei SE goes up to a whopping 11 GPM flow rate. Of course, the overall flow rates can change due to the groundwater temp, but with the possibility of a flow rate going to 11 GPM, this unit is fairly impressive.

The flow rate alone is enough to make this unit an exceptional tank to have inside of the home. The unit can quickly and easily heat up water for the whole house, which means multiple showers can be taken at once in conjunction with dishwashers, washing machines, and more. Another bonus is the 15,000 BTU (Minimum) / 199,000 BTU (Maximum) provided by the unit.

Reason #2 to Choose This Product: Circ-Logic Technology

One term you won’t find anywhere else on this list is Circ-Logic, and it comes with this unit. But what exactly is Circ-Logic technology and why is it beneficial to anyone who owns this gas tankless unit? Well, Circ-Technology is super water heating that allows this propane-powered unit the ability to recirculate hot water within the pipes while in use. This means that incoming water that has already been heated to the ideal temperature can be recirculated to other parts of the home, giving you access to the hot water flow more readily.

Reason #3 to Choose This Product: Convenient and Compact

You might notice that all of these best tankless water heaters have the advantage of being convenient and compact. It is one of the main reasons why people buy these superior water heating devices. But the RU199iP Sensei SE takes it a step further. This propane-powered device is designed to be so convenient and compact that it can be installed in some of the most non-traditional locations throughout the whole house, including crawl spaces and closets. That means you no longer have to worry about the behemoth taking up over 16 square feet of space in your home.

Secondly, this propane water heater is completely replicable. This means that any part that breaks or needs replacing on this gas-powered device can be swapped out with ease. This saves money in the long run, as you won’t have to worry about buying an entirely new propane-powered system – simply replace the broken pieces and get back to enjoying your energy-efficient heater.

There is one more way in which this device is convenient to the buyer – the life expectancy is 20 years, which is at least 10 more years than other units.

All in all, the RU199iP Sensei SE is a superior water heating device with excellent flow rates, unlike anything you will find in other devices. Yes, it is a bit more pricey than other tanks, but it’s well worth the money – especially considering you will be saving money in the long run.

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#3: Rinnai V65eN Tankless Hot Water Heater, Large (Best Gas Tankless Water Heater)

If you are looking for a natural gas water heater tankless system, then the Rinnai V65eN Tankless Hot Water Heater is an excellent choice. The company has a wide selection of tankless water heaters to choose from, all of which have high star ratings and raving reviews. As far as the Rinnai V65eN Tankless Hot Water Heater is concerned, it has over 200 positive reviews with customers stating “Very good folks. I couldn’t believe how small this unit [is]” and “Super Energy Efficient”.

The company prides itself on being the company that “puts an end to scheduling hot water needs”. The Rinnai Tankless Water Heater will never run out of hot water, even when you have the shower, washing machine, and dishwasher all running at once.

One major highlight of this natural gas water heater is that it isdesigned with a ThemaCirc360 Technology which is able to recirculate hot water through pipes with incredible speed, giving you hot water quickly when you need it. With traditional systems, you would need to wait for the heat to travel, wasting around 24 16-ounce water bottles each time. This problem can now be avoided thanks to state-of-the-art developments in the Rinnai V65eN Tankless Hot Water Heater.

What’s more to love about this tankless hot water heater is that it is surprisingly small (about the size of a small suitcase), which ultimately puts the days of larger-than-life traditional water heater tanks to rest. The super-compact design of this water heater means that you can install it almost anywhere – even in the attic or closet. 

Now let’s take a look at the energy efficiency factor. With the Rinnai V65eN Tankless Hot Water Heater, it’s all about affordability and efficiency. This model not only cuts CO2 emissions thanks to the natural gas design, but it also uses far less energy while conserving water. In fact, this tankless water heater uses 40% less energy since it only heats water when you’re using it.

Some other unique features you will find with this hot water heater is WiFi monitoring which allows for quick and easy monitoring right from your phone and a life expectancy of over 20 years, far more than a traditional hot water heater. It also offers a respectful max BTU’s of up to 120,000 and a max energy factor of 0.82. 

All in all, this tankless natural gas water heater is one that you can trust. Plus, it’s priced right at just $680.40 plus shipping. Rinnai has been a leader in the industry for over 100 years, which gives buyers automatic peace of mind when purchasing. They are the #1 trusted sellers for natural gas tankless water heaters and continuously strive to enhance their water heaters.

#4: EcoSmart ECO 27 Tankless Water Heater (Best Low Cost)

If you want to install a tankless hot water heater in your home but don’t have too much money on hand, then you’re likely looking for a solution that combines quality with a price tag you can feel comfortable with, and that’s where the EcoSmart ECO 27 Tankless Water Heater comes into play. This high-quality water heating device is priced at only $460.62 with free shipping, and customers love it. In fact, this product has over 2,000 positive reviews on Amazon. Those are facts you can depend on!

But what’s the buzz about the EcoSmart ECO 27 Electric Tankless Water Heater? Why is it so popular and continuing to rise to the top of the charts in terms of price and quality? Well, there are a few different reasons. Let’s take a look at the top features of the EcoSmart ECO 27 Tankless Water Heater.

  • You Save Money. Money rules the world, and we don’t want to spend all of our hard-earned money on energy bills. What customers love about this tankless water heater is that it can save up to 50% on your typical heating costs. That means more money in your pocket every month thanks to energy efficiency.
  • Handy Digital Temperature Control. Dealing with a traditional tank can be a major hassle and forget about fiddling with the temperatures. The EcoSmart ECO 27 Electric Tankless Water Heater makes it easier than ever before, though, with a convenient digital temperature control complete with 1-degree increments for complete control and operation of your tank. (Activation flow is 0.3 GPM.)
  • Designed With Copper and Stainless Components. The combination of copper and stainless components is beneficial in a number of ways. For one, they are more efficient and can hold in heat better than other materials. Secondly, they are far easier to replace (if necessary) so you can spend less time worrying about replacement parts and more time relaxing with hot water.
  • Compact and Stylish. Didn’t think a tankless water heater could be visually appealing and a great addition to the home? Think again! Unlike traditional tanks, this device features a compact style that can fit almost anywhere and has a modern, stylish design that works well in any home. 
  • Never Run Out of Hot Water. Perhaps the biggest benefit of owning a tankless water heater is that you never have to fear losing hot water, even with multiple people taking a shower at once.

Another important benefit with this tankless water heater is that it can handle all types of climates, hot or cold, which is not always applicable to these types of tanks. In areas where water temperatures dip down to 37 degrees Fahrenheit, the ECO 27 will be able to heat 3 gallons per minute for up to 2 showers at a time. In warmer climates, the ECO 27 provides 6 gallons per minute for up to 4 showers at a time.

If you want a tankless water heater that is known for energy efficiency, being compact and sleek, and able to work in any climate, then the ECO 27 may be the top option. Plus it’s priced right at under $500 – that’s a steal for a piece of equipment like this. Join the other 2,000+ positive reviewers on Amazon and buy this tank now!

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#5: Camplux 10L 2.64 GPM High Capacity Color Screen Propane Tankless Water Heater (Best Propane Tankless Water Heater)

For some consumers, propane is the only way to go. The good news is that there are tankless water heaters designed utilizing propane, just as the Camplux 10L 2.64 GPM High Capacity Color Screen Propane Tankless Water Heater does. The best part is, it’s built from a trusted company that thrives on providing top-of-the-line products, and this tankless heater is priced at just $229.99 plus free shipping.

There’s a lot to love about the Camplux Tankless Water Heater. The small, compact water tankless water heater is specifically designed for medium hot water production, which is ideal for smaller spaces like an apartment or cabin. The tank is specifically designed using a 120-volt power cord combined with an exhaust fan for safety and a color screen. It operates using 0.4 PSI with a maximum output of 68,000 BTU per hour.

Camplux is designed with safety in mind that goes beyond the exhaust fan and color screen, though. This tech-savvy propane tankless water heater utilizes an innovative combustion technology with multiple protection systems including an airflow pressure switch, automatic flame cut off, and protection from overheating as well as freezing. Together, these safety features allow the user to remain relaxed and confident.

Aside from being a convenient, small, and safe device for any smaller home or apartment, the Camplux 10L 2.64 GPM High Capacity Color Screen Propane Tankless Water Heater is also constructed with efficiency in mind. With this model, you can achieve high thermal efficiency at around 88.5%, which means you will save big time on those pesky monthly energy payments. 

Last but not least, let’s take a look at the ease of use the Camplux 10L 2.64 GPM High Capacity Color Screen Propane Tankless Water Heater has to offer. Instant hot water is as easy as a touch of a button and you can easily adjust the temperature of the water using the available summer/winter switch. The LED temperature display is big and easy to read so you know exactly what the output water temperature is at any given time.

Installation is also a breeze. The device comes with an inlet connector of ⅝” UNF inverted flare male with a ½” BSP water fitting. It can quickly and easily be installed indoors and comes with a safe and highly efficient ventilation system for optimal use. It also comes with approved adapters to enhance the ease of use and safety of the tank.

If you’re looking for a propane tankless water heater, then this is one of the top water heater models to choose from. It’s cheap and effective while also remaining high-quality and safe, two factors which are both incredibly important when it comes to water heaters.

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What About the Cheapies? Our Best Products Under $X

#1 Best Under $500: Rheem 240V 3 Heating Chambers RTEX-24 Residential Tankless Water Heater

Tankless heaters don’t always have to be super expensive. If you are in need of a high-quality device that is on the cheaper side, without being too cheap, you will enjoy the Rheem 240V 3 Heating Chambers RTEX-24 Residential Tankless Water Heater. It’s a tad pricier than the other low-ballers in this section, but it’s still a reasonable price for an outstanding water heater.

This is one of the top tankless heaters on the market that you can get for under $500 – in fact, the product is priced at a nice $485.99 with free shipping. Too much money upfront? Do you need to make payments? Then you will be glad to know that the  Rheem 240V 3 Heating Chambers RTEX-24 Residential Tankless Water Heater also offers payment plans, too. 

So what exactly do these water heaters have to offer? 

  • Easy to Use. One of the issues with water heaters – especially of the traditional tank water heater variety – is that they can be difficult to operate. If you don’t know what you’re doing, you can really mess with the water temperature. Aside from that, the bulky tanks can be difficult to work with in general. These water heaters are different. They come complete with an external digital thermostatic control and with an easy-to-read LED display, showing temperatures with 1-degree accuracy. That means that you can readily change the water temperature with just a click of a button.
  • Self-Modulation Technology. We have seen this technology mentioned here and there in this must-see list of water heaters, and by now you know that it’s a very good thing to have. With self-modulation, you won’t spend a penny more than what you actually use. It is one of the top ways to enjoy energy efficiency from an energy-efficient appliance.
  • Made with Copper Immersion. Copper is known for its ability to hold in heat and water temperature with ease. Having copper means that you won’t have to worry about losing heat anytime soon. The copper is also durable and reliable as well as easily replaceable when the time comes. The  Rheem 240V 3 Heating Chambers RTEX-24 Residential Tankless Water Heater comes with a three-heating copper element for ultimate success.
  • Easy Installation. Unlike traditional tank water heaters, these water heaters are designed to install quickly and easily. This means less time fussing with cold showers and finally being able to hop into the shower with your favorite water temperature. You’ll need only a few minutes to configure it!
  • Superior Flow Rate. With a superior flow rate of 5.9 GPM, users can feel confident in the product they are buying.
  • Aesthetically Pleasing. Ditch those grotesque, larger-than-life water heaters and replace them with the  Rheem 240V 3 Heating Chambers RTEX-24 Residential Tankless Water Heater. This device is sleek and snazzy with a silver exterior that suits any contemporary home with ease.

Altogether, the  Rheem 240V 3 Heating Chambers RTEX-24 Residential Tankless Water Heater is one of the top water heaters in the market. If you want to spend less and indulge in a perfect water temperature, superior flow rate, and easy installation, you will find this device is the one for you.

#2 Best Under $200: EcoSmart ECO 11 Electric Tankless Water Heater

Purchasing a tankless water heater for your small home or apartment should not have to cost an arm and a leg – and that’s what the EcoSmart ECO 11 tank is all about. We already know that EcoSmart is a company we can trust, so opting for this cost-effective yet highly durable, reliable, and high-quality heater is a no brainer. Did we mention it’s only $192.47 with free shipping and has over 1,000 positive reviews on Amazon?

There’s so much to love about this EcoSmart model – not just because the company is leading the industry with innovative equipment, but because the huge number of features makes the purchase worth every cent. This tank in particular utilizes self-modulated technology that allows for control over energy output, making this one of the most energy-efficient tankless water heaters in the market today. 

The EcoSmart ECO 11 is specifically designed to accommodate smaller areas, so keep that in mind when deciding which model to purchase. It can also be used for small point of use applications, too, making this a versatile piece of equipment anyone can find useful and enjoyable. 

With the EcoSmart ECO 11, you will receive 2 gallons of hot water per minute, and the supply is virtually limitless. However, it’s also worth mentioning that this product should only be used in warmer climates as it is optimal to be used with water at 67 degrees Fahrenheit. That’s not to say it “won’t work” elsewhere, it just won’t work as good in colder climates, and hot water output may be a bit slower. 

An added bonus of opting for the EcoSmart ECO 11 water heater is that it only turns on when you need it. In turn, this cuts down on energy bills and can save you up to a whopping 50% on your water heating costs. That’s a definite bang for your buck! 

Last but not least, this tankless water is known to be one of the smallest devices on the market. It has a sleek, yet sturdy design that can easily be fixed onto the wall. This offers a major difference from traditional hot water tanks, which are huge, bulky, and unsightly no matter where they are placed. But the ECO 11 is different – it saves space and looks great whether it’s mounted in the hallway, closet, basement – you name it. 

Needless to say, for less than $200 you can get your hands on a highly efficient and affordable tankless water heater. The EcoSmart ECO 11 water tank is everything you need to enjoy hot water in a clever and aesthetically pleasing device. 

#3 Best Under $170: Bosch Electric Mini-Tank Water Heater Tronic 3000

Anyone who has ever been camping, or doing something similar, may struggle with the fact that there is a lack of hot water. Carrying around a water heater is less than ideal – if not impossible. So what’s the camper enthusiast supposed to do? How can one get hot water when there is truly no access to it? The answer is a miniature water heater. 

The Bosch Electric Mini-Tank Water Heater is our number one pick when it comes to portable water heaters that get the job done and get it done right. It is the most convenient hot water heater on the market. Simply plug it in under your sink and enjoy 4-gallon, point of use hot water in an instant with a thermal efficiency of 98%. 

Now, when some people hear the word “portable” or “point of use” they automatically think of something flimsy that may have a tendency to break easily. This simply is not the case with the Bosch Electric Mini-Tank Water Heater. This portable hot water heater is known for its long-lasting quality, which means you can take it just about anywhere without hassle, thanks to the premium glass-lined material.

Worried about installation? Although other water heaters – especially traditional tanks – most likely need professional installation, this portable, point of use hot water heater is easy enough to do it all on your own. The 36.3” cord plugs into any 120-volt outlet or any kind of in-line source that provides a hot water. It’s a cinch, even for beginners.

When you’re all plugged in, don’t forget to mount the point of use water heater – which is just as easy, if not easier, than the initial installation. Mounting can be done on just about any shelf, wall, or floor, and the package comes equipped with the brackets needed to do so. When you’re ready, tap into the cold water line, then install the tankless water heater at the sink, and you’re ready to enjoy hot water.

The Bosch Electric Mini-Tank Water Heater works quickly and efficiently and can provide point of use hot water for up to two sinks at a single time. You will love that you will finally have access to hot water whenever you need it and at a timely rate, too. 

For only $169.57 plus free shipping you can get your hands on the  Bosch Electric Mini-Tank Water Heater and join the 1,000+ positive reviewers on Amazon stating “Very impressed with performance so far!” and “Hot Water NOW: Solid, attractive, well built, and easy installation!”

Electric or Gas Water Heater?

A lot of consumers are curious as to which is better – electric water heaters or gas water heaters? Well, the major difference between these two water heaters is their overall energy efficiency. As far as electric water heaters are concerned, they tend to be around 98% or more efficient. When it comes to gas water heaters, the energy efficiency drops to around 85%. Of course, gas-powered water heaters are known for costing much less (per month) than electric water heaters and are known to last longer, too.

Are These Better Than Regular Water Heaters?

Tankless water heaters come with their own range of advantages and disadvantages. The major benefit of tankless water heaters is that they use 30% to 50% less energy than traditional tank water heaters. This energy factor contributes to consumers saving $100 or more every year – although this depends on overall water usage.

Some of the advantages that come with tankless water heaters include:

  • Tankless water heaters only heat water when a faucet is turned on. This means that you don’t have to worry about water being held in the tank for an extended, unwanted period of time.
  • Customers have options when it comes to tankless water heaters with options like natural gas, propane, and electric. They are able to heat water better and provide a supply of hot water to the user. Each style has their own slew of benefits.
  • Tankless water heaters provide an endless supply of hot water. This is especially beneficial to those who are filling large bodies of water, such as a giant bathtub or even a hot tub. The supply of hot water won’t run out like traditional tank water heaters.
  • Lastly, tankless water heaters are more compact and convenient. Standard water heaters are known for being bulky, let alone an eyesore. Tankless water heaters are smaller and can fit in tinier spaces. They are also more visually appealing as well.

Overall, tankless water heaters are known to be able to heat water quickly and efficiently while offering a continuous flow of hot water. They are also far cheaper than traditional tanks and don’t take up as much space. For these reasons, tankless water heaters are known for being superior to traditional tank water heaters.

What are the Maintenance Costs?

It’s true that a tankless unit will cost far less than a traditional unit, but you’ll need to provide maintenance fairly regularly. You’ll need to have the unit professionally periodically flushed to stop minerals and sediments from building up in the tank. This isn’t too expensive, and most other types of maintenance for a tankless unit are around $100 to $800. Keep in mind, though, that most maintenance for a unit is cheaper and the overall lifespan of this type of tank is far more than a traditional tank.


If you want the best value for money, pick the Stiebel Eltron Tankless Heater Tempra Plus.

If you need a propane unit, pick the Camplux 10L 2.64 GPM High Capacity Color Screen Propane Tankless Water Heater.

If you want to keep your spend under $200, pick the EcoSmart ECO 11 Electric Tankless Water Heater.

When it comes to finding the best tankless water heater, it’s important to look at all of the different features such as flow rate and research whether you prefer a natural gas-powered, propane-powered, or electric unit. Every tank on this list has been selected thanks to the superior quality compared to others on the market. With that in mind, you can’t go wrong with ditching your traditional tank and opting for a tankless unit on this list.