Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas

Takagi T-KJr2-IN-NG Tankless Water Heater

Note: This product was discontinued by the manufacturer. We recommend you checkout our updated reviews of the best tankless water heaters on the market today.

Over the last 75 years, Takagi has distinguished themselves from their competition with their sleek, compact designs and technologically advanced features. The newest addition to their product line is the newly revamped Takagi T-KJr2-IN-NG Tankless Water Heater. The T-KJr2 is available in two different configurations: the IN-LP, which is powered by propane, and the IN-NG, which is fueled by natural gas. Both models are the smallest units offered by Takagi, and there is truth in the old saying that the best things come in small packages!

The Takagi T-KJr2-IN-NG Tankless Water Heater is one of the highest rated tankless water heaters in the world in terms of customer satisfaction. At the time of this writing, 79% of reviewers have given it a five-star rating, and another 11% have given it a four-star rating.

What is the allure of this tankless water heater?

Read on to find out more!

Key Features

  • The Takagi T-KJr-IN NG has an impressive maximum flow rate of 6.6 GPM.
  • Outlet and inlet thermistors offer continuous monitoring of the hot water’s temperature.
  • Takagi offers a 10-year warranty on the heat exchanger and a 5-year warranty on the water heater’s parts.


  • This model is Energy Star certified.
  • The water heater works well with hard water.
  • It has a BTU of 140,000 and an energy factor of 0.81-0 .83


    • The unit must be installed by a licensed technician. If the buyer chooses to install it themselves, Takagi will not honor the warranties.
    • In order to install this unit, 4″ Cat 3 stainless steel venting is required, which may result in an additional expense to install it.

    Product Review

    As mentioned earlier, the Takagi T-KJr-IN NG is the smallest tankless water heater in Takagi’s product line. One of its highlights is its low price. At the time of this writing, many retailers are selling the model for under $600 with free shipping. Although cost efficient, the Takagi T-KJr-IN-NG does not sacrifice versatility for price. It can be converted into a direct vent model by using the TV10 conversion kit (sold separately). This conversion kit allows the unit to be installed in a utility closet, garage, or other location where air supply might be restricted.

    Don’t let its small size fool you. The Takagi T-KJr-IN NG is capable of performing the same functions as a 40 gallon storage tank water heater. The use of thermistors enables this unit to guarantee a steady flow of hot water, and its design boasts a unique air-fuel ratio sensor that continually monitors efficiency to reduce potentially harmful emissions. There are safety controls for the hot water temperature, and should the unit develop a problem or become overheated, the internal computer will immediately shut it off. Other safety features included with this model include cold weather protection, internal surge protection, and diagnostic codes all backed by one of the top brands available.

    Because it is powered by natural gas, there is no need for electricity. It has a per hour BTU input ranging between 19,500 and 140,000. The max flow rate of this particular model is 6.6 gallons per minute; however, when a temperature rise of 70 degrees is required, the flow rate only averages 3.3 gpm. Thus, homeowners with a large demand for hot water would be better off looking for a larger capacity model or purchasing multiple units to link together.


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    Takagi strongly encourages buyers to hire a licensed professional to install this unit (if not, the manufacturer warranties will not be honored), and most professional plumbers report that it is quite simple to install. The unit will need to be vented to the outdoors, but venting can be installed either vertically or horizontally. It does require a minimum electric source of 110 volts. The minimum flow activation rate for the Takagi T-KJr-IN NG is 0.5 gpm.

    Thank You For Reading

    At the time of this writing most online reviewers have given this model a 5-star rating. The primary complaint against the model is that it does not offer sufficient power to furnish adequate hot water to the reviewers’ homes; however, this problem can be attributed to many causes (e.g. the homeowner under sizing their hot water needs) rather than the unit itself. With Takagi’s reputation for quality and a solid warranty to back it up, the Takagi T-KJr-IN NG would make an excellent investment for anyone’s home.