The 7 Best Tankless Water Heaters for Your Home: Reviewed, Compared, and Ranked(2024)

Updated on:
January 6, 2024

Tank water heaters are the most common water heating systems in most American homes. However, homeowners have started to accept the benefits of switching to a tankless water heating system.

Tankless water heaters can be up to 34% more energy efficient than traditional storage tank water heaters in households that consume 41 gallons or less of hot water each day. Tankless water heaters (if gas powered) will save households more than $100 a year the longer they are in service. According to the US Department of Energy, electric tankless water heaters still save homeowners roughly $44 per year.

To help you make the right choice for your home, I’ve reviewed the seven best tankless water heaters currently in the market. 

Here are my results.

1. Rinnai Ultra Sensei Natural Gas Tankless Water Heater — 9.4/10 (Best natural gas tankless water heater)

When it comes to gas tankless water heaters, Rinnai is a household name. You could even say their RUR160 Sensei is the “Cadillac of tankless water heaters.” There are two versions in this model category: the RUR160i and the RUR160e. These two have basically the same features. The only difference is the RUR160i is for indoor installations while the RUR160e is for outdoor installations. 


The RUR160 Sensei is designed to be highly efficient. It is recommended for new homes and those in need of an upgrade, as well as instances where an outdated tank-type or a less efficient unit cannot meet the hot water demand of a growing household.

Because the RUR160 Sensei is a condensing tankless water heater, it can harness and reuse exhaust gas to maximize heat efficiency, earning it an Energy Star certification. This also means that homeowners who have made energy-efficient adjustments, such as upgrading to a Rinnai Tankless Water Heater, may be eligible for the Nonbusiness Energy Property Credit, a $300 US federal tax credit.

Both RUR160 condensing tankless water heaters can produce up to 160,000 Btu (British thermal units) and deliver up to nine GPM (gallons per minute) of hot water, making them perfect for supplying hot water to between two and five fixtures working simultaneously.

If your home does not have a dedicated hot water return line, the Rinnai RUR160 comes with a unique technology called ThermaCirc360. This innovation makes it easy to install a thermal bypass valve at the fixture farthest away from the water heater. When properly installed, the device temporarily uses the cold water supply for recirculation.

This function provides quicker hot water distribution throughout the home, resulting in dramatically decreased hot water wait time, increased convenience, and comfort. It also cuts down on energy use and greenhouse gas emissions. 

Here is a list of the RUR160’s advantageous features for your home:

  • A digital water temperature controller is built into the front panel. This feature displays the water flow rate, temperatures, unit combustion hours, fan frequency, and pump cycles. It also displays error codes that come in handy during maintenance or repairs.
  • An ultra low NOx natural gas burner produces 160,000 Btu of heat and delivers nine GPM of hot water.
  • Rinnai Control-R WiFi module (available at an extra) allows you to control and monitor your water heater from any smart device in your home (includes voice activation technology).
  • This gas tankless water heater can be installed in altitudes of up to 10,200 ft.
  • The RUR160 Sensei has a UEF (uniform energy factor) rating of 0.93, which rates the overall energy efficiency of the unit.
  • Safety features include a flame rod, boiling protection, combustion fan RPM check, thermal fuse, frost protection, and over-current protection.
  • Purchase includes a 15-year warranty on the heat exchanger, 5-year warranty on parts, and 1-year warranty on labor.
  • With a compact design that fits in every space, this model can also be used in mobile homes and recreational vehicles (RV).
  • The RUR160i (indoor model) has a direct venting system with a concentric vent and a twin-pipe PVC/CPVC arrangement, giving it more versatility than other Rinnai non-condensing variants.
  • An optional filter can be installed in the water heater to prevent sediment buildup. 
  • ThermaCirc360 technology delivers fast hot water even without a dedicated return line.
  • This model can use propane or natural gas.
  • An optional Hugo X-1 battery backup system, built exclusively to run your Rinnai tankless water heater without electricity for several days, will also keep your computer or mobile phone charged until power is restored.
  • Reliable customer support is available round the clock.
  • The Rinnai RUR160 models have an extended 20-year lifespan.


Tankless water heaters are more expensive to purchase and install than standard storage tank water heaters. There are no exceptions with the Rinnai RUR160 models. The indoor model costs $2,244 whereas the outdoor version costs $1,554 (due to the particular PVC/CPVC plumbing layout, the indoor model is more expensive). The cost per unit is rather significant when you include the $120 WiFi controller module, and the $1,587 Hugo X-1 battery pack.

Tankless water heaters, even natural gas types, require electricity to operate or regulate, so if the power goes out, so does your hot water. A tankless water heater may not be the ideal option if you live in a region prone to power outages.


Despite the hefty price tag that comes with both models of the Rinnai RUR160 Sensei, it is quite simply the best water heater available on the market today. RUR models save space and are easy to install and maintain because of their light and compact design. They provide unlimited hot water in constant supply, quickly, and with minimal energy and water waste.

While the initial cost may be a deterrent, bear in mind that this tankless water heater, with its extended 20-years lifespan and energy savings, will pay for itself in the span of a few years.

If you need a tankless water heater that will supply hot water to your entire household without any issues, check out the Rinnai RUR160 Sensei Tankless Water Heaters today.

2. Rheem Professional Classic Series — 8.3/10 (Best electric tankless water heater)

Rheem is well known for manufacturing dependable, low-cost gas and electric units that are simple to install and maintain. Their RTEX-36 Professional Classic Series is the best electric tankless water heater for your home. 


The RTEX-36 tankless electric water heater provides endless hot water on demand for single point-of-use applications such as sinks, showers, or bathrooms, as well as multiple other uses throughout the home. The compact low profile design of Rheem’s eight-gallon per minute point of use electric tankless water heaters allows them to fit conveniently in tight spaces, such as under kitchen counters and bathroom sinks.

This electric tankless water heater can supply quick and continuous energy-efficient hot water for entire households with up to two or three bathrooms. 

The Rheem RTEX-36 tankless electric water heater is perfect for houses and families with significant demands because this technology offers a constant supply of hot water efficiently and only when needed. The integration of modern technology, innovative features, and professional-grade quality are some of the benefits of this tankless water heater.

Here are some notable RTEX-36 performance features:

  • Robust copper immersion heating components with brass tops that boost longevity and are threaded for easy replacement
  • A digital temperature control display that allows you to control water temperature in increments of 1°F ranging from 80°F to 140°F
  • Advanced self-modulating system available that adjusts electricity to suit your household’s hot water demands
  • Free UPS ground delivery throughout the continental United States
  • Five-year warranty on the heating chamber and one-year warranty on parts
  • Compact and lightweight design
  • Easy installation: For flex hose installation, compatible with 12- and 34-inch water connections, no venting or T&P valve necessary
  • Ideal for big homes, homes with an undersized main system, or homes undergoing renovations where point-of-use heaters might increase comfort and convenience
  • Heats water only when needed, resulting in cost savings of up to 50% when used in a point-of-use application or 34% when utilized as a whole-home solution
  • Instantly produces sufficient hot water, eliminating the need to wait and saves both time and water


Just like the Rinnai unit mentioned above, this premium electric water heater also comes at a big-ticket price. It’s available for purchase for around $1,650. Also unlike the Rinnai tankless water heater, this Rheem unit has a shorter lifespan, usually between 7 and 10 years.

Despite stating on the brochure that this electric tankless water heater has a cost savings of up to 50%, it’s worth mentioning that electric versions tend to have higher operating costs than gas-powered alternatives. Therefore you should be ready for a spike in your energy bills when using the Rheem RTEX-36 tankless water heater.

This electric water heater does not have an energy star rating, thus it’s not liable for any federal tax rebates.


The Rheem RTEX-36 Professional Classic Series electric tankless water heater is ideal for single point-of-use or numerous applications that require continuous hot water on demand.

It provides water to entire households with up to two or three bathrooms, and has a compact and lightweight design that can fit anywhere in your home, a self-modulating system that adjusts energy use according to hot water demands, easy installation, and a five-year manufacturer’s warranty.

3. The EcoSmart ECO 11 Electric Tankless Water Heater — 7.6/10 (Best budget tankless water heater)

The EcoSmart ECO 11 electric tankless water heater is one of the smallest and most affordable tankless water heaters I’ve reviewed to date. But don’t be fooled by its miniature size, this water heater packs quite a punch!


This 13-kilowatt electric tankless heater can provide enough water for a single location, such as a kitchen or bathroom, or a small residence. It’s a cost-effective choice that warms water just when you need it, resulting in little waste and electricity use. It’s especially useful for those who live in cities where the water flow is pretty constant, but it may also be used in more isolated regions provided the water flow can be maintained.

At around $250, this affordable water heater provides great value for money. The ECO 11 can provide continuous hot water at up to 2.6 gallons per minute. This inexpensive water heater offers excellent value for money at roughly $250. It will not only deliver rapid and reliable hot water, but it will also do it with guaranteed energy savings of roughly 60%.

Here is a list of features that sets apart the ECO 11 on-demand hot water heater from other tankless water heaters on this list:

  • This tankless water heater can adjust its own energy output for maximum performance thanks to a patented self-modulating technology.
  • The output temperature is shown on a digital display that may be adjusted in one-degree increments.
  • The entire unit measures 11.5 x 8 x 3.75 inches and weighs only 6.5 pounds—perfect for small apartments and mobile homes.
  • This tankless water heater has a highly efficient Uniform Energy Factor of 0.98.
  • This model’s element, electronics, and exchanger are all covered by an EcoSmart lifetime warranty.


The ECO 11 is a “point of use” design, which means it should (preferably) be positioned at the faucet where you’ll require the quickest hot water supply (e.g. the kitchen sink or a main bathroom shower). This has been a concern for several consumers since, due to a lack of storage space in a small apartment or home, the unit must be positioned in a prominent area.

Also, because the self-modulating process takes time, expect a flow delay of 15 to 30 seconds after turning on a faucet. According to user feedback, when the heating element has been active for a length of time, the delay time shortens.

Another thing to keep in mind is that cleaning the ECO 11 will take some time, maybe more than with other tankless heaters. To keep it in excellent working order, the components must be washed down every few months, but this is a little price to pay given the benefits it provides.

The system must be installed by a professional or a licensed plumber in order for the manufacturer to honor the warranty. The warranty will be invalidated if you install it yourself.


If you’re thinking about going with a tankless water heater, the Ecosmart ECO 11 is a great option. This affordable tankless water heater will be a great addition to your home as long as it is properly placed. This product’s main advantage is its ability to save energy. The equipment, on the other hand, is quick, efficient, and simple to install in your home.

This is not a high-capacity water heater and is not recommended for large families or households. However, for individuals who just want a little amount of hot water, the Ecosmart ECO 11 will suffice. This is especially beneficial for people seeking a more environmentally friendly “hot water on demand” option.

4. Bosch Tronic 3000 2.5GL Gallon Semi Tankless Water Heater

The Bosch Tronic 3000 2.5GL water heater is not what I’d call a full tankless heater. It’s a mini-tank water heater that is distinctly made to fit under kitchen counters, sinks, and other tight spaces within your home.

With its tiny and lightweight form, this $182 water heater is so simple to operate that it only needs a simple tap to deliver hot water. The aesthetics of this under-sink water heater set it apart from other current versions in terms of outward appearance, while the glass-lined interior ensures its endurance.

It’s also a high-scoring water heater because of its quick recovery rate, which means you won’t have to wait as long for hot water. Because of its pressure release valve, it actually ensures perfect safety. 

Some of the interesting features of the Bosch Tronic 3000 2.5GL include a fast recovery rate that supplies hot water to up to two sinks simultaneously, a conventional 120 VAC plug-in (1440 watts), a clean and stylish style that can blend well with any environment, a compact size that’s perfect for apartments, RVs and boats, a six-year unit warranty, and a two-year parts warranty.

Some of the downsides I came across while reviewing this unit were customer reports of a damaged anode that turns water brown due to oxidation (Bosch does specify the need to replace the part annually), the six-year warranty only applies if the water heater is installed by a professional, reports of leaks due to corrosion, and an unresponsive customer support department. 

All in all, the 94% thermal efficiency of the Bosch Tronic 3000 2.5GL gives it an edge over the competition when it comes to heating water. If you want to bring home a sleek and feature-rich under-sink fast water heater, the Bosch Tronic 3000 2.5GL is a good option to consider.

5. Stiebel Eltron Tempra 12 Plus (12 KW) Electric Tankless Water Heater 

The German-made Stiebel Eltron Tempra 12 Plus (12 KW) electric tankless water heater is a popular and cost-effective thermostatically controlled point-of-use tankless water heater for low-flow applications, such as single sinks in restrooms, kitchens, and pool-house showers. Even in moderately warm locations, this model is not deemed adequate for whole-house solutions.

This $698 tankless water heater has a compact design and is probably the most technical unit I’ve reviewed. 

It features a microprocessor-controlled temperature management system, as well as a simple digital temperature LCD display and dial selection that lets you adjust the desired water output temperature anywhere between 86 and 140 degrees Fahrenheit.

The Tempra 12 Plus will adapt its power output to meet fluctuations in incoming water temperature and flow rate, ensuring that the required water temperature is maintained accurately.

Stiebel Eltron’s proprietary dynamic Advanced Flow Control technology is also included in this tankless water heater. When the unit’s sensors detect that the flow demand exceeds the heater’s capacity, this technology automatically regulates the flow of water. 

This function is especially beneficial if you have occasional high flow demands but live in a cold area or have an electrical grid that does not allow for the installation of a larger model. It’s also useful in situations that require high output temperatures for temperature-sensitive applications (in dishwashers, for example) and flow rates aren’t always consistent.

Just like other tankless water heaters I reviewed, the Tempra 12 Plus has its fair share of disadvantages. Some customers I talked to complained of purchasing faulty units that failed safety inspections by city inspectors during home renovations while others complained of not getting sufficient hot water from their fixtures.

6. Eemax Electric Water Heater

The Eemax EEM24018 Electric Tankless Water Heater is lightweight and compact, making it easy to place practically anywhere in your home. The sleek design won’t change the look of the room in any way. The Eemax Electric Tankless Water Heater looks great and is inconspicuous no matter where you put it.

Looks aside, this tankless water heater includes some interesting features, including self-modulating technology that allows the water heater to regulate the amount of energy needed based on the amount of hot water being delivered. It can also provide hot water for up to four showers or sinks simultaneously, and it includes a five-year leak warranty, and a one-year warranty on parts.

The reason this water heater ranks low on my list is that a lot of users have complaints about its build quality. I discovered reports of the unit failing after a few years of use even though the manufacturer claims a 20-year lifespan. There are also complaints about hot/cold water temperature fluctuations while using the heater. 

There are indeed some drawbacks with the Eemax EEM24018 Tankless Water Heater, but there is no such thing as a perfect tankless water heater, although the Rinnai RUR160 series comes close.

7. Camplux 5L Portable Propane Tankless Water Heater

For those who are always on the move, the Camplux 5L Propane Tankless Water Heater is your best choice for your hot water needs regardless of where you go camping.

For activation, the 5L Camplux Propane Tankless Water Heater just needs 2 PSI of gas pressure. This tankless water heater has one of the lowest activation requirements compared to the great majority of other natural gas tankless water heaters, hence, even if your gas intake flow is extremely low, this device will function just fine.

The Camplux outdoor gas tankless water heater has a capacity of 1.32 gallons per minute, which is on the lower end of the spectrum. It does, however, allow this device to supply hot water for a prolonged period. The propane unit, which has a power output of no less than 34,000 Btu/hr, requires a minimum pressure of 0.4 PSI. Also, to use this tankless water heater, you’ll need a 12-volt water supply pump. It also comes with a one-year warranty.

As with the Eemax unit above, there are a lot of complaints about the build quality of the Camplux gas tankless water heater, with some users claiming that the unit started falling apart after a few months of use. However, most online reviews are generally positive.

If you need a portable tankless water heater, the Camplux outdoor tankless water heater will sort out your hot water needs so you can focus on enjoying the great outdoors.

The Bottom Line

I spent a whole week trying to find the best tankless water heater that money can buy. In the end, the Rinnai RUR160 Sensei Natural Gas Water Heater proved to be the most obvious choice.

I like the fact that there are two available versions of the same water heater (an outdoor version and an indoor version). It also incorporates myriad technical features that ensure optimum delivery of hot water whenever I need it. 

These features include a WiFi-control module for remote control and monitoring, ThermaCirc360 technology for fast hot water delivery even without a dedicated return line, an ultra low NOx natural gas burner that produces 160,000 Btu of heat and delivers nine GPM of hot water, a compact design that fits in every space, an optional Hugo X-1 battery backup system, ability to use propane or gas, 15-year warranty period, and a 20-year guaranteed extended lifespan.

Despite the hefty $2,244 price tag on the indoor version (RUR160i), and $1,554 on the outdoor version (RUR160e), both these tankless heaters provide excellent value for money. If you factor in the $300 Nonbusiness Energy Property Tax Credit, you should start to enjoy the return on investment within a few years.

If you need more information on the Rinnai RUR160 Sensei Natural Gas Heater, visit the website today.

Best Water Heaters Review Methodology

I used a four-step review process to find the best tankless water heaters on the market.

Step 1: Reviews

The first step was to read customer reviews for the major tankless water heaters in the United States. This necessitated hours of research on Consumer Affairs, Amazon, Lowes, Walmart, and the Better Business Bureau’s website, among others. Finally, I compiled a list of trustworthy tankless water heater manufacturers in two categories: gas-powered and electric-powered. In each category, there were an average of eight manufacturers. My work was cut out for me.

Step 2: Checklist

For the next step, I made a list of the major features I’d look for in a modern tankless water heater, including water flow capacity, electricity/gas consumption figures, price or affordability, safety and convenience features, after-sales service and support, ease of installation, and environmental friendliness. Any unit that did not meet at least 75% of the requirements on my stringent checklist was eliminated from the list.

Step 3: Speaking With Real Customers

With the shortlist of dependable water heaters at hand, it was time to track down customers who had made a purchase and speak with them about their experience. So, with the help of my partner, and a few friends, we put up “lemonade and cookies” stands in various hardware and retail stores in my town and handed out free beverages and cookies to anyone who wanted to chat about their experiences with the water heaters on my list. It was a costly endeavor, but I was determined it would pay off.

Amazingly, over 60 people turned up, and by the end of the day, I had gathered enough information to eliminate a few more firms from my list.

Step 4: Speaking With Customer Support Departments

This final step was contacting the remaining tankless water heater manufacturers’ customer service representatives and pressuring them to respond to some of the negative customer reviews they had received. This allowed me to see how each manufacturer dealt with negative feedback and how considerate their customer service representatives were. Because I don’t condone disrespect, I eliminated any manufacturer with unprofessional or unpleasant support personnel from my list as well.

In the end, I had managed to come up with a list of the best tankless water heaters that money could buy.


It took an entire week of rigorous research to find the seven best tankless water heaters, and the Rinnai RUR160 Sensei Tankless Water Heater proved to be the best of them all.

There’s a lot to like about this tankless water heater. For instance, it will supply hot water simultaneously to up to five fixtures in your home, provide myriad safety features that ensure your family and pets are not exposed to harmful emissions or electric currents, ThermaCirc360 technology for fast hot water delivery even without a dedicated return line, and WiFi remote control with voice activation, and it includes a $300 Nonbusiness Energy Property Tax Credit, a Uniform Energy Factor of 0.93, and 15-year warranty period.

There’s also an optional Hugo-X1 battery pack that will ensure hot water supply for days after a power outage (including charging your cell phone and other devices). Additionally, Rinnai provides round-the-clock customer support in case you need any assistance.

If you need a tankless water heater that will never disappoint you in any way, check out the Rinnai RUR160 Sensei Tankless Water Heater today.

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