Takagi Tankless Water Heater Reviews – 2022 Guide

| Last Updated: July 3, 2021

Whenever you are looking for water heaters, the Japanese name Takagi will definitely come up.

So whether you are looking for a heater for your new house or need to upgrade your current heater, your next option could be a unit by Takagi.

Let us go through some of the main points regarding these heaters so you can choose the most robust one.

  • Best tankless water heater
  • Has a temperature range of 100-185 degree Celsius
  • Water flow rate is of 10 GPM
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  • Comes with inlet and outlet thermistors for constant temperatures
  • Reliable and durable as it is manufactured in Japan
  • Ideal heater for radiant heating applications
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  • Best for the money
  • One of the best heaters for energy conservation
  • Equipped with computerized safety features
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  • Best Takagi Tankless Gas Water Heater
  • Water connection location is placed at the bottom
  • Excellent flow rate of 10.00
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  • Best Takagi Outdoor tankless water heater
  • Maximum flow rate is of 8.0 GPM
  • Inlet and outlet thermistors are there for constant temperature monitoring
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  • Best Takagi Commercial Tankless Water Heater
  • Remarkable flow rate of 14.50
  • Easily reach to the water connection location from the bottom
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How Does Takagi Compare to the Competition?

The market is full of state-of-the-art heaters. Some of them are tankless and some of them are electric, but Takagi stands out among its competitors due to the following reasons:


If you are looking for a heater that offers you heated water on demand, then investing in a Takagi tankless heater is one of the best ideas. You will get hot water as soon as you turn on the tap, making these different from tank heaters. So, the idea of on-demand heated water makes Takagi different from its competitors.

Energy Consumption

If you are an advocate of energy and resource consumption, then tankless heaters of this brand stand from other brands, as well. As there is no tank to store heated water, you don’t have to worry about energy being wasted without reason. This is the reason tankless heaters consume less electricity, and thus, the bill would be less than with typical units. 


As compared to its competitors, Takagi tankless heaters are more reliable and durable. They are designed and crafted in a specific manner that can last for at least a couple of seasons.

Comparison of the Best Takagi Tankless Water Heaters

To help you choose some of the very best Takagi tankless water heaters, we have jotted down a comparative analysis. This will help you determine which one is best in terms of energy resources, size, cost, unit size, fan motor features, and multiple other aspects, as well. These different numbers or features will help you choose the most suitable tankless water heater.

Model NameUnit Size (L”xW”xH”)UEFCost of Unit Only
T-H3S-DV-N11.2×17.8x 24.90.94$1,129
Takagi TK-510C-NI20.25×13.75×9.500.80$1,630

Review of the Best Takagi Tankless Water Heaters

We have carefully picked the top Takagi Tankless Water Heaters, so have a look at the main features and pros and cons of these and choose the very best one. 

Best Overall and Best Tankless Water Heater

Takagi T-H3-DV-N

Takagi T-H3-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 10-Gallon Per Minute, 199,000 BTU


Max Water Flow (GPM): 10

Energy Factor (EF): 0.93

Dimensions: 11.25″ x 17.75″ x 23.63″

Water Temp Range: 100-185°F

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Why it Stands Out to Us

Where to start? This Takagi tankless water heater is called the best overall for a reason; there are so many factors that make this heater stand out to us. Firstly, it is extremely easy to install. But if you are moving to another house or looking for an upgrade, you might need to install some bigger pipes. Moreover, its features show that it is lightweight and comes with a remarkable flow rate, which makes it easy to install and move around. In addition to this, it is capable of working in extreme weather conditions, especially when the temperature is going through such extreme and drastic changes. All things considered, it is built to conserve energy, which makes it extraordinary from the other units in the market. Among all of these factors, another important point is that whenever this heater is working, it is always silent.

Bottom Line

This remarkable, condensing, high-efficiency natural gas indoor tankless water heater provides endless hot water, is extremely compact, easy to install, environment-friendly, lightweight, does not make much noise, and will not take up much space in your house. So, if you are looking for all of these features in a heater, then stop wondering and start investing. Save yourself from the trouble of washing your face with cold water and take advantage of its multiple features!

The natural gas makes sure the water is at the right temperature throughout time. More importantly, if this device detects any cold water, it immediately triggers its heating system. The minimum and maximum capacity of this remarkable tankless heating system are 199,000 to 19,5000. So if you find it difficult to take a shower in cold water or even at a moderate temperature, then you need to invest in this heater. Moreover, if you live with a large family or have some guests coming up in the cold season, then this machine is a savior.


Provides an endless supply of hot water

Easily satisfies the rule for low-emissions

Provides on-demand usage of heated water

Equipped with multiple computerized safety features

Comes with remarkable energy conservation features


Shows a flame error when not installed perfectly


Takagi T-H3M-DV-N

Takagi T-H3M-DV-N Condensing Direct Vent Tankless Water Heater, Natural Gas


Max Water Flow (GPM): 6.6

Energy Factor (EF): N/A

Dimensions: 17.75″ x 13.12″ x 29.5″

Water Temp Range: N/A

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Why it Stands Out to Us

This robust piece of technology stands out to us because of multiple reasons. One of the reasons is that it uses existing 1/2” gas supply lines along with some PVC venting to reduce installation costs. It also comes with multiple safety features such as freeze, overheat, surge protection, and troubleshooting diagnostic codes. This hot water tank supplies hot water, both directly and indirectly, to hot water systems, and one can easily use these supplies as recirculation systems, storage tanks, radiant floor systems, and hydronic heating systems. You can also use it for domestic and heating applications. These are some of the features that make it stand out to us.

Bottom Line

This tankless heater is energy qualified. It involves a 15-year limited heat exchanger and five-year limited residential parts warranty. The primary heat exchanger uses commercial-grade copper alloy and ensures it is 25 times more efficient compared to the performance and efficiency of stainless steel. On the other hand, a secondary heat exchanger uses around 316L of stainless steel for improved corrosion resistance. It offers integrated control and power controls, making sure that everyone benefits from its features very well. So, it is time you consider investing in this tankless heater.


Allows gas input of 120,000 BTU

A perfect heater for fewer family members

Comes with internal freeze protection system

Equipped with stellar hydronic heating systems

Features exhaust and water temperature safety control


Sometimes it gets loud

Best for the Money

Takagi T-H3S-DV-N

Takagi T-H3S-DV-N Condensing High Efficiency Natural Gas Indoor Tankless Water Heater, 8-Gallon Per Minute


Max Water Flow (GPM): 8

Energy Factor (EF): 0.95

Dimensions: 11.25″ x 17.75″ x 24.88″

Water Temp Range: 100-140°F

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Why it Stands Out to Us

The very fact that it is budget-friendly makes it stand out to us. So, if you want access to heated water but don’t have unlimited finances, then investing in this would not put a dent in your budget. If you are switching from an electric heater to this tankless one, then you should know that you are making a perfect choice. It is a safer choice, especially, since there is no risk of flooding in case of any emergency. Plus, it is capable of providing on-demand, constant heated water to at least two to three rooms at the same time.

Bottom Line

This remarkable tankless heating system also comes with all of the components required for its easy installation. You’ll find a pipe cover, remote temperature controller, lead-free isolation values & pressure relief values, neutralizer, product preservers, and all of these essential components come with a very detailed, yet easy-to-understand, manual. Moreover, its vent size is only four inches, which is perfect for standard use. As it does not weigh much, it is easy to install and lift. So, if you are living up high or close to the mountains where it is always cold, then investing in this tankless heater will be your savior on cold nights.


Easily affordable for most people

There is no pilot light to worry about

Passes effortlessly on ultra-low emissions

A friendly dimension makes it very easy to install

Compact and beautiful design doesn’t take much on the wall


Vent fan comes on sometimes

Best Takagi Outdoor Tankless Water Heater

Takagi T-K4-OS-NG

Takagi T-K4-OS-NG Tankless Water Heater, Natural Gas, Outdoor


Max Water Flow (GPM): 8

Energy Factor (EF): 0.80

Dimensions: 8.5″ x 13.8″ x 20.3″

Water Temp Range: N/A

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Why it Stands Out to Us

This Takagi tankless heater stands out for a wide number of reasons. Let us name those features one by one. It comes with a 15-year limited heat exchanger warranty and a 5-year limited warranty for residential use, which gives more control to the user over the heater. In addition to this, it also includes a temperature controller as a standard feature. So instead of going outside, the user can increase or decrease the temperature or even manipulate other settings, as well, just by sitting inside. Lastly, you don’t have to place it in the bathroom, so it is fine if you place it outside. These are some of the reasons it stands out to us.

Bottom Line

With a remarkable flow rate of eight and a copper heat exchanger, it is one of the best tankless water heaters on our list. Plus, it saves its user from extra trouble, as it comes with a complementary recess box, pipe cover, remote temperature controller, and even lead-free isolation valves and a pressure relief valve. This one-of-its-kind, natural gas outdoor non-condensing tankless heater is capable of supplying warm water to at least three showers and is capable of supplying warm water to two showers in cooler climates. So, if you are thinking about getting a water heater for your house, then considering this is not a bad option.


No need to install a vent pipe

Comes with 5-year heat exchanger

Easy to fix, so you don’t need a pro to install it

Yearly heating bill goes down to a certain degree

Usually placed outside, so it saves loads of space


Warranty works with licensed repairmen only

Best Takagi Commercial Tankless Water Heater

Takagi T-M50-P


Max Water Flow (GPM): 14.5

Energy Factor (EF): 0.82

Dimensions: 12.25″ x 25.25″ x 24.88″

Water Temp Range: N/A

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Why it Stands Out to Us

The very reason fact it is designed for heavy-duty and commercial use makes it stand out to us. Hotels, restaurants, government sectors, mansions, and other large spaces that need to supply warm water to multiple rooms can make great use of it. With this heavy-duty tankless heater, you would be able to supply warm water to six bathrooms simultaneously in a moderate climate, and in a much colder climate, you would be able to supply warm water to four different bathrooms. These are some of the many reasons this stands out to us. Plus, this is one of the most reliable commercial tankless heaters in the market.

Bottom Line

All we can say is that this is one of the very best heaters one can use for commercial use. So if you are planning upon opening a small stay-house in the middle of the northern mountains and wish to supply warm water to the guests, then considering this heater as your option is a wise decision. Moreover, as it is equipped with dual exchange heater design, it provides reliability and durability. So, consider all of these factors and place this remarkable, environment-friendly heater outside of your restaurant or house and supply warm water to multiple bathrooms, when required.


Capable of maximum 380,000 BTUs

Easy to install and perfect to place outdoors

Made in Japan with non-condensing technology

Comes with a detailed and well-illustrated manual


Heavy but has max BTUs

Best Takagi Tankless Gas Water Heater

Takagi TK-510C-NI


Max Water Flow (GPM): 10

Energy Factor (EF): 0.81

Dimensions: 10.50″ x 13.75″ x 20.50″

Water Temp Range: N/A

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Why it Stands Out to Us

It has a very long list of reasons that make it stand out to us. The very reason that it is smoothly and easily convertible to liquid propane from gas makes it stand out to us. Plus, its concentric vent design makes it more suitable for residential and commercial use. A perfectly designed concentric vent allows both the intake for combustion air and the exhaust vent to pass through a standard roof or sidewall. If you are looking for an alternative to a standard two-pipe intake vent, then this tankless heater is the very best option for you.

Bottom Line

This heater easily allows you to link up to four units without a multi-unit controller. It also features multi-linking, which is capable of connecting up to 20 units. Other than this, investing in this machine is a good idea as it is equipped with multiple safety features. Some of them include freeze, overheat, and surge protection, and it also gives a brief overview of some of the major troubleshooting diagnostic codes. When a tankless heater is offering all of these stellar features, it gets really hard to not invest in it.


Features concentric vent as a vent type

Depth of this heater is around 10 inches

Perfect for residential and commercial use

Heat is exchanged through copper installation

Build on non-condensing technology which is remarkable


Availability of natural gas is a must

What Kind of Warranty Does Takagi Offer?

The warranty is important, as it gives a sense of security to the users, and the makers and curators of Takagi tankless water heaters are familiar with this notion. Therefore, it offers a limited warranty to its user. This limited warranty allows the users or their customers to have some of the legal rights, and these legal rights may differ from state to state. Three types of warranties are offered by Takagi: a general limited warranty, a parts warranty, and a heat exchanger warranty.

The first one is issued for the original retail purchaser only. If there is some sort of transfer of ownership of the retailer, this sort of warranty won’t carry any value. The parts warranty means that if one of the parts of the machine is not working in the very first 24 hours of the installation, then this warranty allows you to get it fixed. The third warranty means that if the heat exchanger fails within the first seven years after the original installation, you would be able to carry on with the normal installation and working. However, some of the elements are not covered in the installation and warranty process. As a consumer, it is important to be aware of those points.

Who is Takagi?

If you want to get rid of all of your heated water-related problems, then no company is better than Takagi. This remarkable, competitive company has been active and serving customers since 1952. Since then, it has been providing high-quality products to solve a wide range of water and heat-related problems.

Takagi is one of the most important tankless water heater brands and has been showing beyond satisfactory performance in North America. They are pioneers in improving the thermal efficiency of the tankless water heater. These heaters work on the Air-Fuel Ratio sensor, ensuring the safety of the heater and house.


Now that all the information regarding one of the very best tankless heater manufacturers is in front of you, we are certain it will be easy for you to make a wise decision. So, choose a unit depending on your needs and budget. Plus, these heaters are very affordable, environmentally friendly, and ideal for any house setting.

My name is Bob Wells and I am a retired HVAC tech from Washington state. I am currently retired and no longer do much with HVAC, however, I feel like I have a lot of knowledge in the subject and I wanted to create a website where I could talk about what I've learned and help upcoming HVAC techs. Find more info about me and HVAC Training 101.