Takagi Water Heater Review

Review of Takagi tankless models with the
advantages and features

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Learn how Takagi water heater design and cutting-edge technology saves you money and deliver reliable and worry-free water heating. Takagi, as the first tankless unit that entered the North American market, offers a good selection of heaters for residential use, such as the popular T-K4, T-KJr, T-H3 and other models. Review the top features and compare them side by side in the comparison chart.

About Takagi Company

Takagi Industrial Co. is the reputable manufacturer from Japan that designs and manufactures tankless water heaters from 1952. Since then Takagi manufacturer has been constantly introducing amazing features and models; including the automatic gas control valve system, computer modulating gas valve and safety system, "direct vent convertible" heater, a unique safety device that utilizes the air-fuel ratio rod, great 95% thermal efficiency rating (T-H1 model), T-M1 as the first multi-gas water heater system for the industrial applications, and much more.

Today, Takagi water heater manufacturer has offices in Japan, US and Canada and to buy one of the Takagi models you have to contact the exclusive dealers or buy online.

Model review

Takagi water heater Company offers a decent selection of gas-fired tankless models for residential and commercial applications; from low demand applications like small offices or condos to the large homes with multiple baths and for industrial usage.

Non-condensing models

Takagi T-KJr2 and T-KJr2U

takagi tkjr

T-KJr2 and T-KJr2U are the smallest tankless water heaters from Takagi that are designed for light residential applications such as the small home or condo with one bath and dishwasher, for example.

Both models are available with the indoor, direct vent or outdoor configuration that operate as a single unit.

The main difference between these two models is that Takagi T-KJr2U is the ultra-low NOx water heater, great for environment conscious users.

Takagi T-K4 and T-K4U models

t-k4 indoor model

Takagi tankless T-K4 are energy efficient water heaters, powered by natural gas and propane gas. The high water flow of 8 gallons per minute makes them a good fit for high demanding homes and can run up to three showers at the same time.

Flexible venting allows the outdoor or indoor installation where the direct venting can be used for spot penetration through the outside wall.

T-K4U models comply with the ultra-low NOx regulations.

emergency plumber

Takagi T-D2 and T-D2U

Takagi T-D2U

T-D2/U is another group of standard tankless and ultra-low NOx models, suitable for heavier residential usage and light commercial applications.

What makes it different from other models is the built-in pump control port that ensures the efficient hot water transfer via the circulation pump.

T-D2 series has a capability to expand its power by using the Easy-Link system while the T-D2U series can also be used in the multi-unit system.

Takagi T-M32

takagi tm32

Takagi T-M32 model with its commercial grade components is used for heavy-duty applications.With the flow rate of 9 GPM it is used as the single unit but is also capable to utilize both Easy-Linked and Multi-Linked system to meet high water flow demands.

Great venting flexibility allows installation inside, outside and with the direct venting option. It is also available as the ASME version but it does not use the heat exchanger made from durable copper alloy as other models.

Takagi T-M50

takagi tm50

T-M50 model, with the gas input of 380,000 BTU/hr and water flow of up to 14.5 GPM, is the largest and the most powerful unit from all Takagi water heaters.

This is the commercial unit that can use Easy-Link system to connect up to four units into one system or if using the Multi-Link system up to 10. T-M50 is the only water heater that offers the dual-combustion system, which ensures reliable and efficient work. As the above T-M32 model, T-M50 can be used as the ASME unit but without the HRS35 copper alloy heat exchanger.

Condensing models

Takagi T-H3

Takagi T-H3Takagi water heater T-H3 is the ultra-efficient unit that uses the tankless and condensing technology for potable water heating, also space heating and in recirculation systems.

It complies with the ultra-low NOx standards and is recommended for homes with three to four bathrooms and light commercial applications such as beauty salons, restaurants and offices.

This versatile unit is capable to provide the efficiency of 0.95, and connect into multi-unit systems.

Takagi T-H3J

Takagi T-H3J is similar to the above T-H3 model; it is also condensing unit with ultra-low NOx emission, has high energy factor but does not have capability to operate in the multi-system and therefore provide more power and hot water. Its gas input is also lower which results in lower supply of hot water, one to two baths only.

Takagi T-H3S

Takagi T-H3S is a model between T-H3 and T-H3J that is designed to supply enough hot water to homes with the maximum of three bathrooms, simultaneously. It doesn't have the capability to use the Easy-Link and Multi-Unit systems so it operates as the single unit only.


Takagi water heater is an ideal solution for the homeowners looking for versatility; from heating potable water and space heating to the application in recirculation systems. From the smallest model T-KJr to the largest T-M50 you will find models that have great energy efficiency, are environment friendly or "green", use less energy, meet or exceed the Low NOx standards SCAQMD and preserves the natural resources by using 95% recyclable materials.

Takagi water heater like other tankless appliances provides on demand and endless supply of hot water, and with the sophisticate features allows the steady flow of hot water with less fluctuation. All units use different features to protect the unit, like flame sensor, air control, hi-limit switch, thermistors, overheat sensor and multiple ceramic heaters to prevent the unit from freezing when the surrounding temperature drops too low.

Takagi uses the small computer for the proper unit operation and to maximize the efficiency and reduce the emission of carbon monoxide. This computer monitors and adjusts the air/fuel ratio and therefore, the quality of the gas combustion. LED error code is used for troubleshooting.

Takagi manufacturer is the only manufacturer that offers Direct Vent convertible units.


Every Takagi water heater used in residential applications has a warranty of 15 years on the heat exchanger and five years on all other parts. Warranty on commercial use is only 10 years.

Old popular models

Takagi water heater T-H2 is the high efficiency unit, advertised as "green" and condensing water heater and designed as the direct vent indoor model T-H2-DV and outdoor T-H2-OS.

Takagi T-K3 used to be the most popular Takagi model, designed for the mid size homes with up to five family members, where two showers and a sink can operate simultaneously.

Old Takagi T-KJr model is reviewed here.

See also how Takagi compares to Noritz and Rinnai.

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(Pictures courtesy of Takagi)