Top Water Heaters - Updated August 2017

Our experts reviewed hundreds of water heaters and have picked the best 5 available on the market.

Best Value

Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater


Ecosmart ECO 27 Electric Tankless Water Heater


Best of the Best

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater


Stiebel Eltron Tempra 24 Plus Electric


Rinnai RL75iN Natural Gas Tankless Water Heater


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Low, budget-friendly price for low flow demand. Excellent energy conservation and enough flow for a medium-sized family. A long-lasting, consistent unit from a trusted brand. The Advanced Flow Control really makes a difference, and the device looks great. High flow output and capable of producing 180,000 BTUs.
You can't always run multiple taps and a relatively high minimum GPM. Lower flow than some others. Although installation is simple, doing it yourself voids the warranty. Short warranty and tenuous pressure with multiple applications. Fairly expensive and exceeds the flow requirements of most homes.
For small homes, this is an energy-saving, affordable option. Great for the environment and your wallet, plus no ventilation! Propane is cheap and this unit will likely last 10 years. A good choice. A nice, premium electric option made with German quality. The right choice for those with high plumbing demand.

Contenders


Tankless water heaters have a lot of benefits over traditional water heaters. Perhaps most importantly, they heat water on demand instead of storing hot water in a tank, so they consume less energy. They're also more compact, and some can even be placed outside the home. Although tankless water heating systems are typically more expensive to have installed professionally, the units are affordable and some can be installed by handy homeowners.

This list represents the best tankless water heaters on the market, fit for every budget. We've also included a range of output capacities, features, and installation requirements to make the choice easier.

Considerations


Price

People expect a water heater to last at least a decade, and for this reason are more willing to pay for quality. Tankless heaters are usually more expensive than the traditional alternative, but we've included tanks on this list fit for every budget. Prices range from a few hundred dollars to over $1000.

Features

Temperature control is a key feature for any water heater, whether you can manage the temperature remotely or through the panel and what level of control you have. Water heaters should also come with extensive safety features and a solid warranty.

Installation

Installation requirements vary between gas and electric models, and some warranties require you to have a professional install the unit to avoid potentially dangerous defects. The size and durability of the unit will also be taken into consideration.

Heat Output & Flow

Water heater capacity is measured by both flow, or gallons per minute (GPM), and by heat output, described in BTUs. Picking the right water heater for your home and lifestyle is essential, especially to maximize the energy-saving potential of the unit.

Price


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Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater

As the most wallet-friendly water heater on this list, it's easy to understand that it is intended for use in small homes or for low to medium output. At just $309.00, those with low output needs couldn't ask for a better deal. For this price, though, you won't get anything extravagant like self regulation or digital controls. You may also find it difficult to meet the 1.5 GPM minimum needed to engage the unit.

Ecosmart ECO 27 Electric Tankless Water Heater

This unit is available on Amazon for $442.81, a significant discount from list price. Even as a budget unit, however, the Ecosmart ECO 27 Electric Tankless Water Heater packs a powerful punch, delivering up to 6 GPM worth of self-modulated heat. With a focus on energy conservation and saving money, this water heater is bound to pay for itself many times over before needing to be replaced. Being that it's an electric heater, installation is also somewhat simpler.

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater

As we move up in price, so do we increase flow capacity and convenience of installation. The Takagi T-KJr2-IN-NG Indoor Tankless Water Heater is compact and powerful for only $544.99. It does require ventilation, but is as small as the first two models on this list. The warranty is only valid with proof of professional installation, however. This unit says it's intended for use in small homes, but it's maximum 6.6 GPM is suitable even for some large families.

Stiebel Eltron Tempra 24 Plus Electric

The list price for this unit starts at $915.00, but you can get it from Amazon for only $749.00. If you're looking for a premium electric tankless water heater, this is the product for you. It appears to have a modest flow rate, but customers rave about the long lasting, uninterrupted flow of this unit with multiple applications. Like the Ecosmart, the Stiebel is also electric, and so much easier to install if you already have a suitable breaker.

Rinnai RL75iN Natural Gas Tankless Water Heater

While the rest of the units on this list have been suitable for average families of 5 or less, some homes have greater needs. Providing a tremendous 7.5 GPM of precisely heated water, the Rinnai RL75iN Natural Gas Tankless Water Heater starts at $979.79. It is the priciest water heater on this list by a couple hundred dollars, but well worth the price if you have a large house and high hot water demand. This device will work with multiple showers AND multiple appliances working at once.

Features


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Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater

This small output machine uses only 2 Watts of power when idle, and 10 Watts in use, making it ideal for small properties where energy conservation is important. It also features automatic ventilation to ensure natural gas fumes are safely expelled outside. A digital display tells the current temperature setting, while the actual water and gas controls are manual knobs. The low price of this unit is reflected in the relatively short 2-year warranty.

Ecosmart ECO 27 Electric Tankless Water Heater

Those at Ecosmart believe so definitively in this device that they've given it a lifetime warranty which transfers to the next homeowner. They also employ hyper-reactive self-modulating technology, which Ecosmart claims will save users up to 50% on water heating costs. These almost unbelievable guarantees are backed up by the overwhelmingly satisfied consensus of the Ecosmart ECO 27 Electric Tankless Water Heater's reviews. Users both praise customer service and report lower bills. Set your desired water temperature to the degree with this unit's stylish digital interface, or even with the use of a separately sold remote.

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater

This unit dependably measures the temperature of incoming and outgoing flow with thermistors, and adjusts energy use to compensate. That means a better retention of temperature with fewer spurts of cold water, as well as superior energy conservation. Settings are easy to control using either the wall-mounted display or the remote. This unit comes with a 10-year warranty for the heating element and a 5-year warranty for parts, contingent upon installation by a licensed professional.

Stiebel Eltron Tempra 24 Plus Electric

Customers really loved the ease of use with this unit, as the stylish interface makes it easy to control temperature with a digital screen and simple analog settings. It is made in Germany and offers 7-year leak protection warranty and a 3-year parts warranty. These warranties are valid only after installation by a licensed professional. To eliminate temperature fluctuations, this unit regulates the flow with Advanced Flow Control, which some customers have complained causes slight variations in pressure.

Rinnai RL75iN Natural Gas Tankless Water Heater

This model offers tamper-proof settings on an easy-to-read digital display and push-button settings. This display includes and error code indicator. Interestingly, the maximum temperature for residential units is 140 degrees Fahrenheit, while it is usually set to 120 degrees to avoid scalding. The Rinnai RL75iN Natural Gas Tankless Water Heater has the most complicated warranty structure yet, with 12-year heat exchanger, 5-year parts, and 1-year labor for residential warranties. These are all contingent upon professional installation.

Installation


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Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater

As with all the water heaters on this list, if you do not feel comfortable installing your own unit, it's best to hire professionals. This water heater is gas powered, and its ventilation leads horizontally outside the home. Some consumers note that the ventilation pipe is 2.5” steel and can be difficult to find on your own if you need more length. In addition to ventilation, this unit requires a 110 volt electric supply. This is also one of the smallest heaters on our list, fitting for its capacity, at 15x24x4 inches.

Ecosmart ECO 27 Electric Tankless Water Heater

It's important to note that although this is an electric water heater, and therefore has no need for ventilation, it still requires a considerable amount of electricity to function and so many require an upgrade to your existing breaker. The company recommends running this device from a 200 amp breaker, though some users report being able to run it from a 150 amp breaker. Do not attempt to run this from 100 amp breaker, such as those found in older homes. This Is another small unit that can easily be mounted on the wall, measuring 20x20x6.5 inches.

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater

This small box measures 13.8x20.3x6.7 inches, on the small side for a tankless water heater. Unique on this list, the Takagi T-KJr2-IN-NG Indoor Tankless Water Heater uses propane, and like natural gas water heaters, requires ventilation. It also requires a 110 volt electric supply, like the Eccotemp. Users repeatedly praise the simple installation, especially if you already have existing ventilation. If you don't mind voiding the warranty, this is the simplest unit to install yourself.

Stiebel Eltron Tempra 24 Plus Electric

This electric unit has many of the same requirements as the Ecosmart. It requires 2 60-amp double pole circuit breakers, for a total of 120 amps, and should ideally be run from a 200 amp breaker. It also requires installation by a professional to keep the warranty, but the installation is made simpler without the need for ventilation. At 21.5x19.5x8.8 inches, this is another unit which should easily fit tucked away in any home.

Rinnai RL75iN Natural Gas Tankless Water Heater

As the largest unit on this list, the Rinnai RL75iN Natural Gas Tankless Water Heater measures 14x23x9.3 inches. Its size is understandable for its flow capacity. Similarly, the gas and water fittings are also larger than the others, at 3/4”. You will also need a slightly larger electrical supply of 120 volts. Like any gas water heater, this unit requires ventilation, which must be taken into consideration before installation.

Heat Output & Flow


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Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater

The Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater has the lowest flow of any on this list at 3.4 GPM. Similarly, it produces just 74,500 BTUs. This means that some users find themselves unable to use hot water from multiple faucets at once, especially because the minimum flow for this unit to engage is 0.9 GPM. Some users report minimum flow being as high as 1.5 GPM. This unit is really intended for use by just one or two people at a time.

Ecosmart ECO 27 Electric Tankless Water Heater

Interestingly, Ecosmart offers a large variety of water heaters depending on your geographic location in the United States, as well as your flow demand. The ECO 27 is designed to function anywhere between 3 GPM and 6 GPM depending on your location, applying a little over 90,000 BTUs. Chances are, your actual results will be somewhere in between, around 4-5 GPM. Incredibly, this unit only needs a minimum of .25 GPM to engage.

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater

Using up to 140,000 BTUs to heat up to 6.6 GPM of continuously hot water, the Takagi T-KJr2-IN-NG Indoor Tankless Water Heater offers tremendous performance and great energy conservation. A 40 gallon tank of propane can last up to 2 months providing a family of 4 consistent hot water. Users report that the minimum GPM required to engage the unit is between .5-1, leaving it somewhere between the Eccotemp and the Ecosmart, but effective enough for most homes.

Stiebel Eltron Tempra 24 Plus Electric

It's difficult to determine the exact GPM flow available from the Stiebel Eltron Tempra 24 Plus Electric. The Advanced Flow Control technology explains that instead of simply running out of hot water and producing cold water, like most water heaters, this model with slightly reduce pressure to all applications, keeping all the temperatures steady. Some customers notice this difference in pressure, but most reviewers are thrilled with the steady, ready supply of seemingly endless hot water. It creates 82,000 BTUs, making it similar to the other electric device on this list.

Rinnai RL75iN Natural Gas Tankless Water Heater

The amazing power of this unit produces a range of BTUs between 10,300 and 180,000 per hour. This amount of energy is needed to heat the impressive 7.5 maximum flow output. Requiring less than .5 GPM to engage, this water heater is ready to produce instant hot water for high, multiple-application demands. Gas-supply lines should be double-checked to make sure they can properly supply the Rinnai RL75iN Natural Gas Tankless Water Heater, though chances are, if your home is large enough to require this water heater, it has high-capacity gas-supply as well.

Best of the Best


Homes of 3-5 don't typically need the high-flow, 10 GPM water heaters some contractors may suggest for their home. Instead, you simply need reliable hot water for the rare times all the plumbing in your home is running at once. For such applications, the Takagi T-KJr2-IN-NG Indoor Tankless Water Heater meets all your needs.

Operating on inexpensive propane, installation and maintenance is easy. Regular use means consuming a gallon or less of propane a day, representing considerable savings over most other heating methods. Additionally, the 6.6 GPM flow ensures your family will never run out of water, no matter how many taps you run at once.

The Takagi name is trusted and supports many loyal customers. Become one today by investing in their affordable, whole-home tankless water heater.

Best Value


For more humble applications than devices like the Takagi or Rinnai, the Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater is intended for use by small families of 3 or less. Some people use it for vacation homes and cabins which are only visited occasionally.

It's easy to set your desired temperature with no added bells and whistles. For such a small unit, it produces a respectable 74,000 BTUs, bringing you quick and reliable heat. Although the warranty may seem short, for the price, and considering this unit may pay for itself in the first year, we think it's fine.

Users were especially impressed with how little energy it uses when not engaged. If you have a small family or an infrequently used but small property, this is the ideal value model for you.