Best Tankless Water Heaters - Reviews & Top Picks

Looking for the Best Electric ,Gas or Propane Tankless Water Heaters ? You've come to the right place.

Tankless water heaters are sweeping the nation as an alternative to bulky and wasteful water tanks.

But what if you aren't really sure how they work?

Or what if you're skeptical that making the switch is the right decision for you?

Here is my ultimate guide to find the top tankless water heater.

Hi there, my name is Anderson and I've been in the HVAC business for more than a decade now, and I know my way around water heaters. I can say with absolute confidence that tankless water heaters are the way to go.

Not only are they faster, more affordable and more convenient than traditional water heating systems, but they're also much more eco-friendly. You can save hundreds of dollars and thousands of gallons of water per year by switching to a tankless system!

Are you still unconvinced? You don't have to take my word for it. I've put together this guide so homeowners from all walks of life can see how tankless water heaters will change the way they warm up their taps. If you're considering an upgrade, let this guide answer all of your questions about tankless water heaters.

Top Rated

Stiebel Eltron Tempra 24 Plus

If you're looking for the best electric tankless water heater on the market, the Stiebel Eltron Tempra 24 might be exactly what you need. Not only is it a high-tech, energy-efficient system, but it's also one of the most highly-rated by homeowners across the country.

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Best Value for Money

Ecosmart ECO 27

ecosmart ECO 27 REVIEW

If you're looking for a water heater that you can control to the degree, this is the unit for you. The ECO 27 comes with a variety of functions and features that give you complete mastery of your hot water output.

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Best Budget Model

Rheem RTE 13


If you don't have a lot of money to spend on a tankless water heater, you may be wondering if it's even an option for you. The answer is "yes," and with something like the Rheem RTE 13, you won't even notice the difference between an affordable and a top-model brand.

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Top 11 Tankless Water Heaters : Comparison and Ratings

Here is a comparison of the top tankless water heaters based on their fuel type,price,ratings,flow rate and customer reviews. In short,the overall best tankless water heater award goes to Stiebel Eltron Tempra 24 Plus and the best value for money award goes to Ecosmart ECO 27 . (This model is worth every penny you spend and is a top-rated product.)



Flow Rate





*Top Rated*
Stiebel Eltron
Tempra 24 Plus

   - Electric

- Whole house




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ecosmart ECO 27 REVIEW

*Best Value*
Ecosmart ECO 27

      - Electric




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Takagi T-KJr2-IN-LP review

*Best Indoor Model*
Takagi T-K-Jr2-IN-NG

- Natural Gas
(Also available
in Propane)

- Indoor unit

6.6 GPM



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ECOTEMP L5 review

*Best Portable Model*
Eccotemp L5

- Liquid Propane

 - Portable

 - Comes with
  outdoor shower

1.4 GPM



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rheem rte 13

*Best Budget Model*
Rheem RTE 13

   - Electric




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*Best Natural Gas*

Rinnai RL75iN

  - Natural Gas

7.5 GPM



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ecosmart ECO 27 REVIEW

Ecosmart ECO 18

  - Electric

2.5 GPM



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Rheem RTE 9

  - Electric




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Ecosmart ECO 11

  - Electric

1.5 GPM



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Rheem RTG-64XLN review

Rheem RTG-64XLN

- Natural Gas

- Low NOx

- Outdoor

6.4 GPM



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Reviews by Fuel Used


Check out our guide on electric tankless water heater reviews.

Natural Gas

Check out our guide on natural gas tankless water heater reviews.


Check out our guide on propane tankless water heater reviews.

- General Information -

How Tankless Water Heaters Works

What is a tankless water heater?

To understand it, you first have to understand how traditional water heaters work.

working tankless water heaters

The conventional water heater system has a large tank where hot water is continuously stored. It’s zoomed to your faucets whenever you need it, but it’s also very wasteful because the unit is constantly expending energy to keep the water temperature-controlled even when it’s just sitting there.

There’s also a complicated system of vents, pipes and gas lines that all have to operate in tandem to keep your water heating system fully operational.If this sounds like a lot of work, that’s because it is.

Tankless water heaters are much simpler. Instead of storing, warming and piping hot water from another location, they simply heat up cold water as it travels through the tap.

This is done through small heating units that are attached to the wall and incorporated in your pipes.

Tankless water heaters can be powered by everything from natural gas to electric systems, but they all operate under the assumption that energy should only be expended when it’s actually needed to heat your H2O.

Why Should You Switch ?

All right, you may be saying. I understand what they do. But why should I bother?

tankles water heater

For starters, tankless water heaters can save you hundreds of dollars a year in energy costs. According to the U.S. Department of Energy, you can drastically reduce your energy consumption when you upgrade to a tankless water heater:

  • If you use a small or moderate amount of hot water every day (less than 41 gallons), you can reduce your energy consumption by 24 to 34 percent.
  • If you use a large amount of hot water on a daily basis (86 gallons or more), you’ll save somewhere in the range of eight to 14 percent.

In addition to reducing your energy bill, you’ll also be doing your part to help the environment.

Tankless water heaters are much more eco-friendly than traditional water heaters since they’re only used on an “as-needed” basis.

Remember, you only heat the water directly streaming from your tap when you use a tankless water heater. This means you aren’t wasting water or energy through big tanks sloshing with unwanted water.

All in all, tankless water heaters are an excellent investment for the future. Every family needs hot water, but tankless water heaters will ensure that you don’t rack up huge bills in pursuit of it.

Also check out : 7 Reasons Why you should move to a Tankless water heater

How to choose the Best Tankless Water Heater?

All right! I finally convinced you! Before you swipe your credit card, however, you should make sure you’re buying the right type of tankless water heater for your needs.

how to choose the best tankless water heater

Here are just a few things to consider:

  • Size

The best electric tankless water heater is as small as a book. Others, including gas and propane systems, might require more room for burners, valves, vents and other things of that nature. If it’s important to you that your tankless water system can fit under your sink, be sure to take some measurements before you go shopping.

  • Price

Prices vary so drastically that it’s pointless to give exact numbers. Generally speaking, the more basic systems start at $500 while the bells-and-whistles type can range anywhere from $1,000 to $2,000. You’ll also need to factor in things like delivery, installation and maintenance, so don’t forget these numbers when you’re working up a budget, either.

  • Power

How many gallons do you need your system to pump per minute? What’s your desired temperature rise and flow rate? You might also want to look up the unit’s cost of fuel per BTU (British Thermal Unit). All of these figures will help you determine your home’s hot water needs and the necessary power requirements for your tankless heating system.

Advantages & Disadvantages

Like anything else, tankless water heaters have their drawbacks. You’ll need to be well-informed about their pros and cons in order to make a smart purchase decision.

Advantage: Tankless heaters can save you more than $100 a year on your energy bill.
Disadvantage: They cost more as an initial investment. On the plus side, they’ll recoup their price in just a few short years, and they also have a longer life expectancy. Conventional heating tanks typically last 5-10 years, but tankless water heaters will keep on chugging for 20 years or more.

Advantage: They heat water directly at the tap, eliminating the need to wait around for your hot water tank to re-fill.
Disadvantage: A single tankless heater might not be enough to provide hot water for your entire home, especially if your family requires what’s known as “simultaneous usage.” For example, if you want to run the washing machine at the same time as the upstairs shower, you might need to install separate heating units at both sinks to get simultaneous hot water in both rooms.

Advantage: Electric heating units are eco-friendly thanks to their “as-needed” energy usage.
Disadvantage: Gas-powered heating units can sometimes offset energy savings through their use of gas burners. If your primary reason for buying a tankless water heater is to live a greener life, you might want to purchase an electric heating unit instead.

Types of Tankless Water Heaters

Natural Gas


In a tankless, gas-powered water heater, cold water is drawn into the unit and warmed through a series of burners and heat exchangers. Because they can handle high volumes of water, they’re great for large homes or those with high water demands, and they’re also the most popular model for families who live in very cold climates. However, they’re more expensive in both short- and long-term costs than other tankless models.

  • Provide the highest flow rates
  • Require ventilation, which can mean costly or complicated installation
  • Cost: $500+


Propane water heaters work very similarly to gas water heaters. In fact, among some manufacturers, they’re marketed and sold the same way. The difference is mostly in the way that propane and methane (natural gas) burn, which can in turn affect things like cost, energy efficiency and the longevity of the unit.


  • Work the same as natural gas water heaters
  • May need annual inspections

Electric units are the most affordable option in tankless water heaters. They cost less upfront and don’t require as much maintenance as other models. That said, they can’t supply as much power as gas or propane units, so they’re best for small homes or those with low or intermittent water needs.

  • Small, easy-to-install units
  • Can be fitted under sinks and inside closets

Some Frequently Asked Questions

What is a tankless water heater?

Tankless water heaters warm up your water on an “as needed” basis. Instead of hot water collecting in a water tank in your basement, tankless water heaters directly warm cold water as it travels through your tap.

Are they dangerous?

When properly used and maintained, tankless water heaters are no more dangerous than your existing water heating system. The gas and propane systems do use a live flame, but it’s no different than a gas stove using a pilot light.

Where can they be installed?

This depends on the type of tankless water heater you buy. Many electric units are small enough that they can be stored right under the sink, but gas or propane units need more room because they have burners and vents to consider.

How much do they cost?

Prices vary between hundreds and thousands. Federal Tax Credits are available for certain units and can reduce the price by as much as 30 percent.

Why do they cost more than traditional water heating systems?

They only cost more initially. When you look at the five- or ten-year price of owning a tankless water system versus a traditional water heating system, the tankless version is much cheaper.

How do you save money with a tankless water heater?

For one, the unit itself lasts 20+ years. That’s twice as long as a water tank. Tankless water heaters also waste less energy, and this means a much more affordable bill every month. Multiply those savings by 12 months a year, and that’s why tankless water heaters are so affordable in the long run.

Our Best Picks of Tankless Water Heaters - 2017

It’s time to get down to specifics. If you’re ready to make a purchase and are looking for some brands, models and specs to get you started, here are just a few tankless water heater reviews.

- Best All-Purpose Tankless Water Heater -

Ecosmart ECO 27 Electric


  • Small, self-modulating unit
  • Amazing control over temperature and pressure
  • Lifetime warranty for residential use


  • Minor flow restriction
  • Not suited for larger homes
  • May require re-wiring of other electrical appliances

If you’re looking for a water heater that you can control to the degree, this is the unit for you. The ECO 27 comes with a variety of functions and features that give you complete mastery of your hot water output.

The biggest advantage of the ECO 27 is its size. As a compact electric unit, it can be hidden in cupboards for interior design purposes or mounted on walls to free up floor space.

Just don’t think that its small size decreases it efficiency! The ECO 27 can heat almost three gallons of water per minute, and it’s also entirely self-modulating when it comes to energy efficiency.

It uses its own sensors to figure out how much energy is needed to heat up your water, offering you a hands-free experience that’s both convenient and refreshingly free of jargon. You don’t need to be a heating specialist to use this technology.

If you do like to fiddle with settings, however, you should know that the ECO 27 can be adjusted to your ideal temperature down to the degree. Very few electric water heaters offer this level of precision and control. You can thank the unit’s three separate 9KW heaters for its versatility.

One flaw of the ECO27 is that it isn’t really suited to large homes or offices unless multiple units are installed on the property. Like all electric water heating systems, it struggles during high-demand simultaneous usage, so you may have to choose between showering and running the dishwasher. It’s a small sacrifice for all the perks, but it’s still a sacrifice.

Bottom Line​

All things considered, the ECO 27 is one of the most versatile and energy-efficient tankless water heaters for its size.

It may lack the power of larger units, but for a compact system that can be mounted anywhere in your home, its convenience more than makes up for its deficits. Check out the ECO 27 on Amazon to learn more about this great product and what it can do for you!

- Top Rated Tankless Water Heater -

Stiebel Eltron Tempra 24 Plus


  • Easy-to-use interface
  • Reduces annual energy costs by 15-20 percent
  • Reliable temperature control


  • Requires contemporary wiring
  • Short (~30 second) flow delays
  • Automated customer service hotline

If you’re looking for the best electric tankless water heater on the market, the Stiebel Eltron Tempra 24 might be exactly what you need. Not only is it a high-tech, energy-efficient system, but it’s also one of the most highly-rated by homeowners across the country.

First things first:

The Tempra 24 is an electric system, so you won’t need to mess with burners and heat exchangers.

All the work is done for you inside the unit. It’s very safe and very reliable, especially if you have inquisitive children who like to roam around and get into trouble.

It also comes with a digital interface that will always give you the exact data you need in a brightly-lit, easy-to-read format.

Now, electric water heaters usually come with a glaring flaw in the sense that they don’t offer enough power to heat water throughout your entire house. I’m here to tell you that the Tempra 24 is the exception.

Like the name (“Whole House”) implies, this water heater can handle everything from washing machines to jacuzzi tubs with ease.

The secret is in its patented Advanced Flow Control technology, something that keeps your water temperature steady and entirely under your control no matter how many sinks or showers are demanding hot water. Never again suffer a fluctuating flow when you’re trying to get things done!

Make sure to check your electrical panel before buying the Tempra 24 because it needs to support two 60-amp circuits for installation. Unfortunately, if your electrical panel isn’t up to date, the Tempra 24 can’t be fit into your home.

Bottom Line:

It doesn’t get any better than the Tempra 24. Its only major drawback is that it requires up-to-date wiring in your electrical panel, but even if you don’t have it, you can always retrofit the correct circuits and install the Tempra 24 afterwards. Read about the product on Amazon to check it out and other tankless water heater reviews to help you make your purchase decision.

- Best Natural Gas Tankless Water Heater -

Rinnai RL75i Natural Gas


  • Adjustable settings and controls
  • Great for large-volume households
  • Can be converted to propane unit


  • Expensive
  • Can require up to 180,000 BTU an hour
  • Short (~15 second) flow delays

One of the most popular tankless water heaters on the market, the Rinnai RL75iN is what you buy if you only want to buy one water heater in your lifetime. A high-energy, high-tech unit, it comes with everything from combustion fans to digital controllers to ensure that your hot water is delivered exactly how you want it.

It’s also gas-powered, meaning that it can accommodate a large building or bustling household with ease. This isn’t a brand where you need to install multiple units around the house to get hot water at every faucet.

One Rinnai RL75iN is all that’s required to provide hot water for sinks, showers, dishwashers, washing machines and everything in between.

One drawback of this unit is that it needs a moment to lumber to life; users have reported that it can take anywhere from 15-30 seconds before they get hot water for their morning showers.

Once it’s on, however, the same users report unlimited hot water with no interruptions, so it’s up to you to decide if a short flow delay is an acceptable sacrifice for long, hot and luxurious showers.

If you admire the model but hate the methane, the Rinnai RL75iN can be converted to a propane unit, though this isn’t recommended as a DIY project. Talk to a Rinnai technician if you want to make the switch.

The Bottom Line :

With the Rinnai RL75iN, you get what you pay for, and what you pay for is quality. If you’re looking for a workhorse unit that will provide fast, piping hot water for decades to come, this is easily the best tankless water heater on the market. Check out its page on Amazon and see its amazing reviews for yourself!

- Best Portable Tankless Water Heater -

Eccotemp L5 Portable


  • Built-in safety controls
  • Great temperature and water pressure
  • Shower head included


  • Requires 20-80 PSI
  • May require multiple igniting attempts
  • Needs protection from the wind

best portable tankless water heaterbest portable tankless water heaterPerfect for campers, truckers, travellers and construction workers, the Eccotemp L5 is a godsend when it comes to portable hot water. Even if you aren’t sleeping under a traditional roof or washing your hands at a regular sink, the Eccotemp L5 will allow you to experience the luxury of hot water no matter where you are.

When I say hot, by the way, I mean hot. This isn’t a half-hearted unit that spurts out tiny streams of lukewarm water. Thanks to its high-powered propane burners, the water heated by the Eccotemp L5 can actually be uncomfortably hot unless you manually adjust the temperature and pressure controls.

The good news is that the unit comes with mounting equipment and tank accessories already in the box, so you can set up your shower with the buttons just a few inches away if you’d like. It also offers a built-in timer that will shut off the burner after 17 minutes for safety purposes.

Another great benefit of the Eccotemp L5 is its versatility. While quite popular among campers and off-roaders, it also has plenty of uses around the house; many customers, for example, have found it to be a welcome addition to hot tubs and outdoor saunas. If you only need hot water for something special every once in awhile, a portable unit can be much more convenient than hooking up your new device to a complicated stationary system.

A common complaint of the Eccotempt L5 is that the flame of the burner is easily snuffed out, so if you’re using the unit outdoors, make sure you protect it from the wind.

The Bottom Line:

Though not without flaws, the Eccotemp L5 is a worthy purchase if you’re looking for an alternative to traditional water heating systems. It can be used outdoors, around the house and even as a back-up water heater in case of blackouts or other disasters.Read more about the Eccotemp L5 on Amazon to figure out if it’s the right tankless water heater for you!

- Best Budget Tankless Water Heater -

Rheem RTE 13 Electric


  • Affordable price
  • Small, compact unit that can be placed anywhere
  • Easy to install and operate


  • Copper tubing needed
  • Controls by range (small, medium and high) instead of degree
  • Short-term warranty

If you don’t have a lot of money to spend on a tankless water heater, you may be wondering if it’s even an option for you. The answer is “yes,” and with something like the Rheem RTE 13, you won’t even notice the difference between an affordable and a top-model brand.

For one, the RTE 13 carefully modulates its power to ensure that you’re always getting a steady flow rate and an unchanging water temperature. I’ve seen many units in my time that suffer from sudden temperature fluctuations if the water heater gets overtaxed, but this doesn’t happen here. Whether you’re showering, running a load of laundry or even just washing dishes, you can count on the RTE 13 to keep your water temperature consistent.

Another great thing about the RTE 13 is that it’s one of the smallest and most convenient electric systems on the market. Many customers are so awed by its tiny box that they wonder if it’ll even work, but it does! It offers amazing power for its size, and what’s more, it does it all from a unit that can be installed just about anywhere. Say goodbye to huge water tanks or overly elaborate technological systems. The RTE 13 is so small and light that it might just fade into the wallpaper entirely.

You will need copper tubing for this water heater, so if you currently have plastic, it’s time to make a change. The cost of new tubing can sometimes offset the savings you get from the low price of the model, so the RTE 13 might not be for everyone. Check your plumping and electrical panels and use your best judgement.

The Bottom Line:

Small but powerful, the RTE 13 is an excellent choice for the budget-minded. It might not heat every sink running in your house at once, but if you’re smart in using it, it can be a great way to save money on your electric bill without breaking the bank to get it installed in the first place. Order it today from Amazon and see for yourself!

- Best Indoor Natural Gas Tankless Water Heater -

Takagi T-KJr2-IN-NG Indoor


  • Intricate and fully adjustable controls
  • Great for large residences and high-volume buildings
  • Only one unit needed


  • Requires stainless steel venting
  • Warranty voided if not installed by Takagi technician
  • Regular maintenance required for both safety and operational efficiency

Despite being tankless, the Takagi T-KJr2-IN-NG has a lot of similarities to a traditional water heating system, so it’s excellent for buyers who are uneasy or unsure about making the switch. It does require some know-how in terms of how heating systems work and how they need to be maintained, but if you’re willing to do your homework, it’s a system that will operate beautifully and for decades at a time.

The first thing you should know about the Takagi T-KJr2-IN-NG is that it usesnatural gas. This means it needs to be compatible with your existing gas lines and ventilation systems just like a conventional heating unit.

Once the business of installation is done, you can sit back and enjoy hot water delivered to every inch of your home from a single box. The Takagi T-KJr2-IN-NG doesn’t play around; you can even fill a bathtub with it! It’s an amazing unit that operates on a “seen and not heard” level where a fully-functional system is one that you don’t even have to think about. It’ll operate just as silently and efficiently as a water tank.

You’ll also enjoy very simple and straightforward controls with the Takagi T-KJr2-IN-NG. A wall-mounted controller will display options for flow rate, “in” temperature and “out” temperature, so you can customize everything according to your preferences or budget. If you’re concerned about your bill, adjust the settings down; if you want extremely hot water for your next load of laundry, adjust the settings up.

Be warned that the Takagi T-KJr2-IN-NG isn’t a system to cut your teeth on, not unless you’ve done extensive research beforehand.

The Bottom Line :

With all the power of a traditional water heater, the Takagi T-KJr2-IN-NG is a great choice if you’re worried about making the switch. It’ll operate out of sight and just as well as your old unit.

Just make sure that you aren’t taking any chances with the natural gas component; have it professionally inspected and installed if you aren’t confident in your DIY skills.

- Best Value Propane Tankless Water Heater -

Eccotemp FVI-12-LP High Capacity Propane


  • Affordable price
  • Independent controls for gas and water
  • Gas-powered but electronically ignited


  • Average flow rate
  • Outdoor ventilation required
  • Sub-par performance in larger homes

Another solid model from Eccotemp, the FVI-12-LP was specifically designed with smaller homes in mind, so look here first if you reside in a small house or don’t have extreme hot water demands. While it can and does provide hot water to large buildings, it’s best suited for individual and residential use.

The first thing you’ll notice about the FVI-12-LP is its price. It’s very affordable, especially when you consider that it’ll keep saving you money as it lowers your energy bills down the line. You can expect to save between 10 and 30 percent on your annual energy costs overall.

In terms of operation, it uses propane but has a electronic ignition system, so you’ll enjoy the best of both worlds. This dual system also extends to its wall-mounted controls; you’ll have separate knobs for gas and water, and you can control temperature, flow and pressure with a flick of the wrist. The FVI-12-LP delivers three gallons of water per minute, a rate that’s slightly low for a propane water heater but right on par with the average usage of a small home. It can also be used in cabins, cottages and vacation homes, so it’s a great alternative to water tanks if you only require it a few times a year.

Note that you’ll need to install a special outdoor vent to pump out harmful fumes.

The Bottom Line:

If you’re looking for the best tankless water heater for small homes, the Eccotemp FVI-12-LP is exactly what you need. While it can’t quite measure up to those designed for high-volume hot water requirements, it’s a great little system for non-strenuous demands.

A Few Final Words

As you can see, there’s a lot to consider when shopping for a tankless water heater. But don’t get discouraged by all the criteria! It’s easier than you think to make a change, especially if you do your homework and plan things out in advance. Take your time, make your measurements and browse all of your options. Then go out there and buy a tankless water heater that will completely revolutionize the way you use hot water in your home!