Best Tankless Water Heaters of 2017: Our 5 Favorite Picks

Best Tankless Water Heater of 2017


Are you looking for the best tankless water heater? Tankless water heaters have gained popularity over the years because they deliver hot water nearly instantaneously.

With a considerably longer service life than traditional tank style water heaters, the ability to fit into tight spaces, and their environmental appeal, tankless systems are a smart choice for many home owners.

Save Time

Check Out Our Best Tankless Water Heaters NOW

However, finding the right unit to meet your lifestyle and household hot water needs can be a daunting task. We've taken an in-depth look and selected what we feel are the best of the best.

Best Tankless Water Heaters for 2017

Check Price

Stiebel 

Tempra 24

EcoSmart

ECO27 

Takagi

T-KJr2

Rinnai

RL75iN

Rheem

RTGH-95

Fuel Source

Electric

Electric

Gas

Gas

Gas

Location

Indoor

Indoor

Indoor

Indoor

Indoor

Efficiency 

99%

99.8%

82%

82%

94%

Max. GPM

5.0

6.0

6.6

7.5

9.5

BTU

82,000

92,000

140,000

180,000

199,900

Warranty 

7 / 3 years

Lifetime

15 / 5 years

12 / 5 years 

12 / 5 years

Website

Stiebel Eltron

EcoSmart

Takagi

Rinnai

Rheem

BTU - British Thermal Unit is the amount of energy needed to cool or heat 1 pound of water by 1 degree Fahrenheit. It is an excellent metric to use for comparison

GPM - Gallons per Minute of hot water delivered. Also known as the flow rate

Our Best Tankless Water Heater list covers a wide range of tankless units. Both electric and gas, non-condensing and condensing, and a variety of flow rates to meet many different household hot water needs. Although, each of the reviewed units are indoor models, all of the gas units are available in outdoor models as well. 

Keep in mind that there isn't a single "best" choice because every situation is different. However, these are our favorites and we're confident that you can find a unit on the list that will be a good fit for your home and family.



Best Tankless Water Heaters: Electric

Best Electric Tankless Water Heaters

Electric tankless water heaters have many advantages over their gas fueled cousin. Here's a quick list of a few of their strengths and weaknesses, read our article on Gas vs Electric HERE for a more extensive comparison. 

Pro's and Con's of Electric Tankless Water Heaters


Pro's


  • Less expensive than gas units
  • Easier to install since ventilation it not necessary. This also allows them to fit into tight spaces
  • Extremely efficient 
  • Less maintenance required and easier to repair due to the simplistic design
  • Environmentally friendly

Con's


  • ​Flow rate tends to be lower than gas units
  • An electrical upgrade may be required to power the unit since they use a substantial amount of electricity to heat water


Check Price

Stiebel Eltron

Tempra 24 Plus​

EcoSmart

Eco 27

Efficiency

99%

99.8%

 Max. GPM

5.0

6.0

Min. Flow Activation

.50 GPM

.30 GPM

Voltage

240 v

240v

Wattage

24 w

27 kW

Amp Draw

2 x 50 A

112.5 A

Min. Circuit

2 x 50 A

3 x 40 DP

Max. BTU

82,000

92,000

Minimum Flow Activation - The amount of water flowing into the unit to activate or "fire-up" the tankless water heater


Stiebel Eltron Tempra 24 Plus

Electric Tankless Water Heater

At a Glance

Fuel: Electric

Dimensions: 17 1/2"H x 16 5/8" W x 4 5/8" D

Weight: 16.1 lb​

Venting: None Required​

Efficiency: 99%​

GPM: 5.0

Made in Germany

The Stiebel Eltron Tempra 24 is a high-performing, well designed electric tankless water heater with exceptional technology. With a sleek gray finished case and visible controls this unit showcases over 90 years of superior German technology and delivers impressive energy saving performance.

Features
  • Advanced Flow Control - This feature ensures that there won't be any cold water surprises during high hot water demand times. Stiebel Eltron explains this feature like this: "If the demand asked of a Tempra Plus is greater than the unit can handle, Tempra Advanced Flow Control works by slightly reducing the flow of water. Instead of delivering colder water than the set point, a Tempra Plus automatically delivers slightly less water, but at the correct temperature."
  • Smart Microprocessor Technology - Designed with several temperature and flow sensors that continually send readings into a microprocessor, the incoming and outgoing water temperature is constantly monitored and adjusted. When flow rates increase or decrease the Tempra 24 Plus adjusts to deliver a steady output temperature.
  • Electronic Temperature Control - Set the temperature knob on the unit and the water will always be delivered to that temperature.
  • Voltage Input Options - Depending on your needs, Stiebel Eltron offers the option to run the unit at 208v or 240v.
  • Self-Modulating Energy Savings - The heating elements are engaged in stages which allows the tankless water heater to operate very efficiently, saving both money and energy.
  • Safety - Equipped with a high-limit safety switch with manual reset.
  • Very Quiet - Without mechanical switches the Tempra units are virtually silent when operating. 
Warranty

The limited warranty covers 7 years of leakage and 3 years against defects in workmanship and materials. However, installation must be done by a licensed professional. See the complete warranty HERE. 

The limited warranty is the shortest of all the units on our Best Tankless Water Heaters list, which is surprising for such a well designed, quality product. However, the Tempra 24 Plus is loved by those who own it, and the unit should provide 20+ years of service if properly maintained. 

Value

With attention to detail, excellent customer service and pride in workmanship  Stiebel Eltron is clearly a leader in the industry.

The Tempra 24 Plus is on the higher side of the price range, especially for an electric tankless. However, since venting will not be necessary, the installation costs should be substantially lower.

With the trademarked Advanced Flow Control feature and the self modulating technology, the Tempra 24 is among the best of the best, especially if you are looking for a quality unit with years of experience in the industry.

We wish the warranty was more competitive, but, those who own this unit rave about it's performance, and it is clearly built to deliver impressive results and stand the test of time.

One look at the Stiebel Eltron Tempra 24 Plus and it's easy to see why it made our best tankless water heater list.

Performance

The company expects the Tempra 24 Plus to be able to deliver a flow rate of 8.0 GPM if the temperature rise is 20 degrees Fahrenheit. In colder climates, this unit can deliver an impressive 4.0 GPM if the temperature rise is 40F. 

  • Rule of Thumb: A typical shower uses 2.0 to 2.5 GPM

Stiebel Eltron have a wide variety of units in their Tempra Plus line. We like the 24 because we feel it is a strong performing unit that should be able to meet the average household's hot water needs.

The trademarked Advanced Flow Control feature adds a level of protection during high hot water demand times, and ensures that no one in the house will find themselves in cold water!

This unit is designed to deliver, but if your household hot water needs exceed the Tempra 24 Plus model, Stiebel Eltron manufacturers more powerful models.

If you are looking for a whole-house electric tankless this is an excellent choice and should definitely be on your short list!

EcoSmart ECO 27

Electric Tankless Water Heater

At a Glance

Fuel: Electric

Dimensions: 17"H x 17"W x 3.75"D

Weight: 13.75 lbs

Venting: None Required

Efficiency: 99.8%

GPM: 6.0

Made in China

The EcoSmart ECO27 has a sleek, no-nonsense design and impressive lifetime warranty. As a relatively new company, EcoSmart products are rapidly gaining the reputation of delivering solid performance at a budget price.

Features
  • Precise Control: The ability to increase the outgoing water temperature by 1 degree increments. 
  • Self-Modulating Technology: The amount of electricity the unit draws is based on the demand for hot water. Saving energy while still delivering hot water.
  • Digital Temperature Display: Shows the exact outgoing water temperature as it leaves the machine. 
  • Compact: Because this unit has a sleek, compact design, the EcoSmart 27 can fit into tight spaces.
Warranty

​With the only limited lifetime warranty unit that made our list, EcoSmart clearly has confidence in their products. The exchangers, electronics, and heating elements on the ECO27 are all covered under their warranty. 

However, for the warranty to be valid, the unit must be installed by a licensed plumber/electrician within 30 days of purchase. Click HERE for warranty information. 

Value

The ECO27 is a very reasonably priced electric tankless water heater. For the initial price, on-going energy savings due to the self-modulating technology, and the incredible lifetime warranty this unit is hard to beat.

One note to keep in mind, if you are buying this unit, or any other electric unit, to replace a tank style water heater, be sure your household has adequate electricity. If you need to upgrade your household electrical supply you will undoubtedly add substantially to the initial cost. 

The positive customer reviews, lifetime warranty and low entry price helped put the EcoSmart ECO27 on our Best Tankless Water Heater list.​

Performance

EcoSmart is very upfront about the flow rate expectations of their products. The ECO27 should be able to achieve a 2.7 GPM if the incoming water temperature is 37F. However, if the incoming water temperature is 77F, the unit can deliver it's maximum flow rate of 6.6 GPM. 

The popularity the EcoSmart tankless water heaters ​have seen over recent years could be largely because they provide a solid product that is reasonably priced and environmentally focused. Combined with the lifetime warranty the ECO27 is an excellent choice and well worth a second look! 

Out of all of the tankless units on our Best Tankless Water Heater list, this unit delivers the best bang for the dollar!​

Best Tankless Water Heaters: Gas

Best Gas Tankless Water Heaters

Gas tankless water heaters are extremely popular because of their ability to deliver high volumes of hot water. Read our article on Gas vs Electric Tankless Water Heaters for a more in-depth comparison.

Pro's and Con's of Gas Tankless Water Heaters


Pro's


  • Increased efficiency over tank style water heaters
  • Gas fuel is currently less expensive than electricity
  • Capable of delivering a higher flow rate (GPM) than electric units

Con's


  • ​More expensive than electric tankless units
  • Requires expensive venting for non-condensing units
  • Requires more maintenance
  • Emits green-house gases



Check Price

Takagi

T-KJr2

Rinnai

RL75i

Rheem

RTGH95

Efficiency 

82%

82%

94%

Max. GPM

6.6

7.5

9.5

Min. Flow Activation

40 psi

.40 GPM

.40 GPM

Max. BTU

140,000

180,000

199,900

Ventalation

Power Vent

Concentric

Direct Vent

Ignition

Direct 

Direct Electronic

Direct

Electrical

120 v

120 v

120 v

Venting

Non-Condensing

Non-Condensing

Condensing

Maximum GPM - The best flow rate the tankless is capable of delivering measured in gallons per minute (GPM)


Takagi T-KJr2

Gas Tankless Water Heater

At a Glance

Fuel: Natural Gas 

Dimensions: 20 1/4" H x 13 3/4" W x 7 3/4" D

Weight: 33 lbs

Venting: Direct / Non-Condensing

Efficiency: 82%

GPM: 6.6

The Takagi T-KJr2 is a solid performer with plenty of flexibility since Takagi offers this model in both indoor and outdoor options, as well as natural gas and propane fuel options.

Features
  • Environmentally Friendly -  The Takagi T-KJr2 is a Low NOx model which helps reduce nitrogen oxide emissions.
  • Remote Control - A remote control is included as a standard feature.
  • AFR Sensor - The AFR sensor monitors and maintains the combustion of the unit by adjusting the internal fan motor speed to ensure that the air and fuel is at the correct mixture ration. With this feature the T-KJR2 is able to minimize it's emissions while maximizing it's efficiency. 
  • Safety Controls - Loaded with safety features, the unit is equipped with exhaust and water temperature safety controls. It also has a high-limit shut off to prevent overheating, as well as internal freeze protection, and an overheat cut-off fuse to protect the surface of the heat exchanger.
Warranty

The Takagi T-KJr2 Tankless Water Heater offers a  generous 15 year limited warranty on the heat exchanger, 5 years on parts, and 1 year labor. To qualify for the warranty work, the unit must be installed by a licensed plumber, gas installer, or contractor. Click HERE to see the warranty on page 55 of the Owners Manual. 

Value

​With the option of selecting an indoor or outdoor unit, as well as which fuel (propane or natural gas) best fits your location, the homeowner should be able to find a T-KJr2 model that best meets his individual needs. 

The Takagi T-KJ2 is a non-condensing tankless, which means that expensive stainless steel venting materials will need to be used to properly vent the unit. If it will be used in warmer climates, you may want to consider purchasing the outdoor model, as installation expenses will be lower since venting isn't necessary.

Although this is the smallest unit manufactured by Takagi, the K-Jr2 delivers a solid flow of hot water at a reasonable price within reach for the average homeowner.​ If your hot water needs are high, and you like what Takagi has to offer, the company does have more powerful models available.

Performance 

With the water output setting at 120F the T-KJr2 is capable of delivering hot water at a flow rate of 4.6 GPM if the incoming water temperature is 70F. If the incoming water drops down to 40F, the unit's flow rate drops to 2.9 GPM.

The maximum 6.6 GPM flow rate can be achieved when the incoming water temperature is 70F and the hot water temperature setting is 100F.

The company promotes the K-Jr2 as a great fit for "apartments, one bath homes in cold climates, condos and summer cabins." They state that the unit can handle 2 showers in warmer climates and 1 shower in cooler climates, of course.

The T-KJR2 delivers a solid flow of hot water and has a nice range of features with a focus on safety and performance. This is a good choice if you are looking for a straight-forward, easy to use machine. If your peak hot water demand is relatively low, this gas tankless would be a good choice.


Rinnai RL75iN

Gas Tankless Water Heater

At a Glance

Fuel: Natural Gas

Dimensions: 23" H x 14" W x 9" D

Weight: 45.6 lbs

Venting: Concentric / Non-Condensing

Efficiency: 82%

GPM: 7.5

Made in Japan

The Rinnai RL75iN is made for performance. This gas tankless is part of the Rinnai Award Winning Luxury Series which has proudly earned the Energy Star rating. The RL75iN is an indoor model, however, Rinnai manufactures the exact same unit for outdoor installation (RL75eN).

A quick look at what the RL75iN unit has to offer and you'll see why this gas tankless is part of Rinnai's Luxury Series. It's packed full of standard and optional features and it not only delivers exceptional performance, but it also provides all the bells and whistles to put the homeowner in control.​

Features
  • High Altitude - Works in altitudes up to 10,200 feet.
  • Isolation Valves - Isolation valves are included with the unit. 
  • Venting Options - The vent is on the top, but the unit can be vented either horizontally or vertically. This gives the homeowner the choice of venting thru the roof or a wall. 
  • Wi-fi enabled - The unit is wi-fi enabled for the Control-R add-on.
  • Control-R - This add-on feature will allow the homeowner to adjust the temperature from a smart phone. 
  • Remote Monitoring - Select a dealer to monitor the tankless thru Control-R and automatic maintenance alerts will be delivered directly to your smart phone.
  • Scale Detection - This feature alerts the homeowner when lime scale is building inside the unit and flushing is necessary. 
  • Temperature Lock - Set the temperature and lock it into place preventing others from making adjustments.
Warranty

The Rinnai RL75iN Natural Gas Tankless water heater comes with a limited warranty that requires the unit to be installed by a licensed professional who has attended Rinnai Installation Training Classes.

The heat exchanger is covered for 12 years. Other parts and components for 5 years, and Rinnai will cover 1 year of reasonable labor. Click HERE for the complete warranty. 

Value

This gas tankless water heater isn't for everyone. To start with, many homeowners may not need the amount of hot water this unit can deliver, and if the nifty wi-fi remote monitoring and smart phone temperature adjustments don't appeal to you, there really isn't a reason to purchase a wi-fi enabled tankless. 

With that said, we think this is a fantastic unit which is manufactured by a company that has been around for many years. Rinnai stands behind their products with a solid warranty and they are constantly moving their product line to meet the consumers demand for performance, features and technology.

The RL75iN will provide years of service if properly maintained and it is an excellent choice for large homes.​ In addition, it is also certified for manufactured (mobile) homes.

As you might imagine, this is a higher priced tankless. But if your peak hot water needs are high, and the wi-fi technology appeals to you, you really can't go wrong buying  this Rinnai unit.

Performance

Rinnai promotes the RL75iN model of being capable of delivering enough hot water to support 3 showers and 1 faucet based on ground temperature of 70F. 

The unit can achieve the maximum flow rate of 7.5 GPM​ when the temperature rise is 40F. However, even when the incoming water needs to be heated by 75F, the unit can deliver an impressive 4.0 GPM flow rate!

This may be a high priced gas tankless water heater​, but it is also loaded with features and upgrades, and it's capable of delivering a seemingly endless supply of hot water. If you're looking for a high-demand gas tankless, this is an excellent pick.

Rheem RTGH-95

Gas Tankless Water Heater

At a Glance

Fuel: Natural Gas

Dimensions: 18.5" x 9.8" x 27.5"

Weight: 79 lbs

Venting: Direct Vent / Condensing

Efficiency: 94%

GPM: 9.5

Made in Japan

Rheem's RTGH-95 is the only condensing tankless water heater that made our list. This powerhouse of a tankless is loaded with safety features and is designed to not only look good, but to deliver hot water as efficiently as possible. 

Features
  • Water Savings Setting - This feature allows the homeowner the option of decreasing the flow of water through the pipes until the water reaches the set temperature, saving up to 1,100 gallons of water each year.
  • Hot-Start Programming - Minimizes the "cold water sandwich" which sometimes occurs during periods of frequent on/off operation.
  • High Altitude - Capable of operating at altitudes up to 8,400 ft. 
  • Freeze Protection - Designed to protect itself from freezing in temperatures -30F. 
  • Low Flow Fixture Compatible - Industry first minimum flow rate of .26 GPM and minimum activation flow rate of .40 GPM ensures the user will receive hot water even in low demand situations. 
  • Maintenance Alerts -Warning codes will flash and alert the homeowner when service is necessary. 
Warranty

Rheem backs their RTGH-95 model with an impressive 12-year warranty on the heat exchanger and 5-years on parts and labor. See the warranty HERE. 

Although Rheem doesn't invalidate the warranty coverage if the tankless water heater isn't installed professionally, they do strongly recommend that it is "installed by a contractor that is licensed, state qualified and trained on Rheem's tankless products." In other words, the warranty will be void if the unit isn't properly installed.

Value

The Rheem RTGH-95 is a powerful tankless water heater. It is also our highest priced unit to make our Best Tankless Water Heater list. 

Since this is a condensing unit and expensive stainless steel venting materials are not needed, installation costs should be lower, which will help offset the initial purchase price.

Overall, we think the Rheem RTGH-95 provides excellent value for large homes with high hot water needs. It's capable of delivering large quantities of hot water in an incredibly efficient manner. If properly maintained it should last 20+ years.

Performance

The RTGH-95 unit is the most powerful in Rheem's Prestige line and the company states that it should be able to deliver enough hot water to service 3 bathrooms with a temperature range between 85 - 140F. 

  • Recommended Maximum Temperature - The Department of Energy recommends a maximum temperature of 120F

With a 35F temperature rise the RTGH-95 can achieve it's maximum flow rate of 9.5 GPM. What is really impressive with this powerful unit is that with a temperature rise of 100F it can still deliver a flow rate of 3.8 GPM!

There's no need to worry about running a dishwasher or washing machine when household members are showering . . . this tankless was designed to deliver! 

The Rheem RTGH-95 may not have all the tech bells and whistles of the Rinnia, but if you're looking for high water flow and excellent efficiency from a gas tankless, this unit is superb! It's designed to deliver high volumes of hot water without interruption, and it is a great fit for large homes with multiple bathrooms.


Best Tankless Water Heater

As we stated in the beginning of our review, when selecting a tankless water heater there are many variables, therefore, there is not a one-size-fits-all. Our Best Tankless Water Heater List features a wide range of units that fit many different needs and situations. 

Other Resources

Here are some helpful posts that will prepare you to make an informed buying decision: