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Best Tankless Water Heater 2021 | Our Top Picks And Buyer’s Guide

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BEST 8 WATER HOSE TIMERS: COMPLETE BUYING GUIDE AND REVIEW: This extensive write-up has been dedicated to helping you identify the correct tankless water heater for your needs. Complete reviews of all 8 of our favorite items have been included, a summary of the top brands, and a buyer’s guide on how to navigate the category effectively while shopping for your own tankless water heater. Then, we carefully sort through them, highlighting the specific features of each product in the review table below, so that you can make the right decision quickly. Let’s go! Go now!

1.Rinnai V75iN:

There is no need to wait for your faucet to come out of hot water! When you need it, it will always be available. Now, there’s no need for you to pick between chores. Without a hot water retention issue, you can run the dishwasher, do the laundry or take a shower. This revolutionary feature works through the pipes by recirculating hot water so that when needed, you will still have hot water. When you choose this tankless water heater, you can also rely on water savings all the time. Every single moment, there is no need to wastewater.

If you wish to save space, the Rinnai V75iN tankless hot water heater is also yours. It is not bulky, so one inch of space is not wasted. This water heater for indoor installations is small but effective. It has a lightweight nature, which makes it easy to install quickly. It can accommodate a small suitcase, which can be set up in a crawl room, attic or closet as well. The indoor water heater that runs on natural gas will give you a water flow rate of up to 7.5 GPM, making it one of the most powerful around. It also varies depending on groundwater temperature, however.

  • ThermaCirc360 technology
  • No more water wasting
  • Mobile app for remote control
  • Efficient and space-saving
  • Easy to install and use
  • Expensive

2.EcoSmart ECO 27:

The EcoSmart ECO 27 is a lightweight, highly efficient model with enough water heating power for two simultaneous running showers. For a fair price, if you’re on a tight budget, it’s arguably the best electric water heater. Thanks to the proprietary modulation method, which improves energy efficiency by up to 99.8 percent, it can save you up to 50 percent on electricity bills, perfect for a small household, cottage, or cabin. This water heater has a flow rate of up to 6 gallons per minute for those who are interested in scientific data points.

Sure, any tankless water heater worth your cash should allow you to painlessly regulate temperatures, right? Well, with the EcoSmart ECO 27, that is what you get, but with a little twist. In 1-degree increments, it helps you to raise the temps. That way, depending on your own use of hot water, you can set the exact temperature more precisely.

In areas with temperatures as low as 37 degrees Fahrenheit, the ECO 27 can send you up to 3 gallons of hot water per minute. It can heat almost 6 gallons per minute in places where the temperature of the incoming water is high, such as the southern United States. This potentially implies that you can simultaneously control up to four showers and a sink without running out of hot water. Brilliant! Brilliant!

  • Compact, stylish design
  • Stainless elements for durability
  • Occasional bouts of cold water

3.Rheem RTEX-18:

The Rheem RTEX-18 is almost our top pick in our list of electric water heaters and offers great value as either a whole-house solution (typically up to 2 bathrooms) or as an application point of use. It is so lightweight, it could also fit under the counter, offering a lot of versatility in installation locations. The Rheem RTEX series is highly energy-efficient and will help reduce your energy costs, as with many electric tankless water heaters, especially if you upgrade from a full tank heater. Note that 240V and sufficient circuit security will be needed for installation, so make sure you have the correct electrical specifications.

This electric tankless water heater is perfect for a tight installation, the lightweight casing (less than 19 “in the longest dimension and less than 4” thick) will fit in most spaces, whether under the counter or in the back of a small utility room. This heater still packs enough power to be the hot water source for a small to the medium-sized house (great for up to 2 bathrooms), but don’t let the size fool you. Flow rates can be in excess of 4 GPM.

The digital temperature monitor and ease & precision for adjusting temperature will be appreciated by purchasers of this electric tankless water heater. To set your ideal temperature in increments of 1 degree, simply use the dial on the front. This unit is simple and very reliable to manage, too. Because of Rheem’s broad distribution, most of the heating components are easily interchangeable and readily available from many vendors. The aim of this technology is to improve energy efficiency and reduce costs.

  • Rheem Reliability
  • Precise Temperature Settings
  • Install In Tight Spaces
  • Energy Efficient
  • Not For Larger Homes

4.Stiebel Eltron Tempra 29 Plus:

This model by Stiebel is the leading source of our best water heater reviews. It is a great option if you live in cold regions where incoming water temperatures will drop to as low as 40 degrees Fahrenheit, as a high-end device and one of the most efficient tankless water heaters you can find. If you’re looking for a heater with a high flow rate, it is a brilliant option (depending on the temperature of the incoming water, this thing will heat up to 8 gallons per minute).

The Stiebel Eltron promotes a brand-exclusive technology that automatically changes the flow of water when it senses the demand is greater than the heater can accommodate. If you know the meaning of this? Well, that means that, unlike most heaters that start producing cold water when the flow reaches the heating power, you will still enjoy hot water at a constant temperature.

The Eltron isn’t some fluke in our finest water heater roundup. It is one of the few models to change the power based on the incoming water temperature and the flow rate. To maintain the optimal temperature of the water coming out of your showerhead or tap, it will modulate its power output to balance the heating demands of the incoming water. Sweet! Lovely!

You’ll never have to guess at what temperature the Eltron heats water at. In an easy-to-read digital format, it has a large monitor that shows you the temps. In addition, it has a highly sensitive dial selector that allows temperatures between 86 and 140-degrees Fahrenheit to be set. This tankless heater, in short, is excellent in every way. We just wish that it was cheaper.

  • Five-star performance
  • Energy efficient
  • Automatic flow rate
  • Relatively expensive

5.Noritz NRC66DVNG:

A luxury gas tankless water heater with a flow rate to suit most residential needs is the Noritz NRC66DVNG. This model is intended for indoor installation and generates low Nox emissions that can be vented using normal PVC piping. The condensing technology of Noritz helps generate a high 0.91 energy factor, which distinguishes this device around this price point from other gas tankless water heaters. The NRC66DVNG is also the smallest gas unit in this review, offering maximum installation versatility, especially in small spaces.

This model is one of the more lightweight but still manages to equal the performance of far larger models of gas tankless water heaters on the market. The NRC66DVNG can accommodate a flow rate of up to 6.6 GPM, enough to run multiple fixtures or appliances at the same time, running at up to 120 K BTUs. In addition, the energy factor of 0.91 ensures that heat is applied in an energy-efficient and cost-efficient manner.

Specializing in tankless water heaters, Noritz is what they do. In terms of consistency and reliability, such an emphasis on tankless technology has made them a pioneer. They have also developed a world-class customer service agency, offering support and help with every aspect of service installation. Noritz also oversees all aspects of production, ensuring the consistency of materials and construction in the unit.

As you would expect from a company with as good a reputation as Noritz, minimal maintenance is needed for their heaters to be extremely durable. With some of the best warranties on the tankless water heater market, Noritz also supports their quality statements, up to 12 years on certain core components.

  • Highly Efficient
  • Compact Design
  • Remote Thermostat Included
  • Premium Price Point

6.Takagi T-H3-DV-N:

If you want a model that can rival the conventional tank heater, the Takagi T-H3-DV-N is the best on demand water heater in this series. This machine, fuelled by gas, has a flow rate of a whopping 10 gallons per minute, the highest of any roundup water heater. If you’re looking for a single tankless heater that can take care of all your requirements for hot water, this is it.

Its iconic strength thrives on the Takagi T-H3-DV-N. With its superior performance, this heater can provide up to four bathrooms at the same time with a continuous supply of hot water, and three in a colder environment. It has a commendable energy factor of 0.95 as well. It is also a certified ENERGY STAR standard.

Its ability to keep you and your family safe is one of the biggest questions you may have about choosing your tankless water heater. The brains behind Takagi T-H3-DV-N are well aware of this and, as such, have automated the safety functions of this device. All about this heater in terms of safety is on the agenda, from the built-in diagnostics and temperature controls to internal freeze security systems.

A robust commercial-grade copper heat exchanger comes with the Takagi T-H3-DV-N. This particular feature enables it to heat water within seconds on demand. And then there is the direct power vent that provides you with plenty of options inside your home on where to install it. Other notable highlights include the ease of operation of electronic ignition and the ultra-low emission control condensing technology for NOx.

  • Can link with up to four heaters with no additional tools required
  • Comes with factory-installed power cords
  • Allows PVC venting
  • Expensive

7.Bosch Tronic 3000 T 7-Gallon:

Without Bosch Tronic mentioning the 300 T, our reviews wouldn’t be complete. This is a cost-friendly alternative, a great choice if you don’t have the money to splurge on the more costly ones. Make no mistake about it, though; this unit may be affordable, but the functionality does not fall short.

On this list, the Bosch Tronic 3000 T is the smallest water tank. Yeah, it’s smaller even than the Takagi T-KJr2-IN-LP. This thing is so lightweight that it can fit under a sink cabinet. And this heater can fit perfectly with your interior decor since it has an elegant, trendy style.

The 3000 T can be installed practically anywhere, indoors and outdoors. The benefit of it is that this is a heater point of use, unlike other models that need venting, which, by definition, means that it is a ‘plug and play device. In fact, all you have to do to get it to function is simply and easily tap into your cold-water line and install it directly. This heater is perfect for your garage, patio kitchen, basement wet bar or powder rooms, with such versatility.

The Bosch Tronic 3000 T may be thin, but it is impressive in its heating efficiency. It heats water at a temperature range of 65 to 145 degrees Fahrenheit, which is appropriate in a typical household for most requirements. The flow rate of 7 gallons per minute, meanwhile, is more than enough. Note: in 2.5 and 4-gallon capacities, the 3000 T is also available.

  • Compact and lightweight
  • CFC-free foam insulation for optimal energy efficiency
  • Glass-lined tank for extended use
  • Affordable
  • Stylish design
  • Supports multiple placements
  • Not ideal for large homes

8.Titan N-120:


Provides 105 to 120 degrees (F) of outgoing water temperature. Delivers a flow rate at a 45-degree (F) increase of 2.3 gallons per minute. Recommended usage for places where the temperature of the incoming water is above 65 degrees (F). A wall mount style is featured.

  • Retrench of space
  • Energy Saving, UL Certified ETL Lead-Free, and Compliant
  • 29 years in business
  • Patented mounting design
  • Some customers reported as no reliable


Water heaters without tanks have their place, now and in the future. It is almost impossible to imagine that tankless water heaters will become obsolete as the globe shifts to green and sustainable energy. The best part is that, without using a lot of electricity, these units not only heat the water relatively easily but also do so, which means more money in your pocket. And hey, who doesn’t want to make some savings, particularly if it’s on recurring utility bills? The argument we are trying to make here is that now, more than any other time, you’re better off getting a tankless water heater.

Due to its combination of performance and value, our top pick for 2020’s best tankless water heater is the gas-powered Rinnai V75iN. This unit’s energy efficiency will help you save money, while the 7.5 GPM flow rate will be enough for the hot water requirements of most homes. However, everyone’s needs are different, so we recommend reading on for our complete review of this model and our other top picks.

You have to shop correctly, as is the case for any home appliances, however. We hope you have been taken closer to choosing the right model for your situation by the information given here. Above all, we feel that our reviews have helped to shed light on why you would prefer one style over the other.

Manufacturers will continue to innovate, bringing to the market new models with the latest technology, functionality, and features. We will continue to update our rankings and the data available on this page, as they do. Finally, through the form on our contact page, you are welcome to send us any questions you may have concerning tankless water heaters, and we will get back to you. Good luck with your decision to buy and with your new tankless water heater!