Takagi T-KJr2/U Water Heaters

Buying tips and a review of Takagi T-KJr2 and T-KJr2U, smallest tankless water heaters for residential use high efficient and low NOx compliant. Explore T-KJr2/U main features and specifications that are important factors when selecting the right model.

Model and feature review

Takagi T-KJr2/U models are non-condensing tankless water heaters that are found as the standard (T-KJr2) and ultra-low NOx type (T-KJr2U ), which can further be divided into outdoor and indoor models. Both types use natural (NG) and propane (LP) gas for heating, but only with the correct conversion kit as the gas pressure is different. All the models have the same minimum and maximum gas input, including the energy factor of 0.82.

Small and compact size

Takagi T-KJr2/U water heaters have a compact design with the size of only 20"x14"x8" and with a weight of low 33 lb, making them ideal for installation in almost any part of the home, even in small bathrooms and offices.

The great thing is that the wall-mounted installation frees up the floor space for use as additional storage. The small size doesn't prevent Takagi heaters from providing plenty of hot water in endless supply - there will be no hot water shortage ever again. This is one of the most affordable Takagi models.

Ideal for small homes, apartments, condos

With a temperature rise of 30 F, the maximum flow rate is 6.6 GPM, and thanks to the continuous and endless supply of hot water, these units are ideal for homes with one to two baths.

If the heater is used in colder regions where the incoming ground water temperature is approximately 50 F, the unit will provide enough hot water flow to meet one-bath homes, while in warmer areas, where the temperature is around 70 F, the heater can be used for two baths running simultaneously. These models are recommended for smaller houses, cottages, condos, and apartments.

Takagi T-KJr2-IN

Takagi T-KJr2-IN is a tankless water heater that is used only for indoor installation and has an option to use direct vent systems. It comes with the flexible installation option since the venting system can run horizontally or vertically, and when using the power vent, the maximum length is 50 feet. Electric installation is even easier since the power cord is included.

The remote control is included as the standard feature. It allows an easy and convenient temperature adjustment, which is in the range from 99 F to 167 F, also simple troubleshooting since the error codes are displayed on the controller.

Takagi T-KJr2-OS

Takagi T-KJr2-OS is an outdoor model and can be used only outside - it is ventless, and does not require venting. The remote control also comes as the standard feature for the wall mount.

Takagi T-KJr2U

Takagi T-KJr2U is found as an indoor Takagi T-KJr2U-IN and outdoor unit Takagi T-KJr2U-OS, similar to the above models but comply with the ultra-low NOx regulations, making them ideal for regions with strict gas emission regulations.

T-KJr2U also comes with the remote controller, and the temperature can be adjusted from 100 F to 140 F in nine different temperature settings, while the maximum temperature of the above model is 167 F and has 16 temperature options.


Models / Specs T-KJr2-IN T-KJr2-OS T-KJr2U-IN T-KJr2U-OS
Gas input (BTU) 19,500-
Water flow (GPM) 6.6
Energy factor 0.82
Activation rate (GPM) 0.4
Temp. settings (F) 99-167 99-167 100-140 100-140
Energy consumption (Watts) 139 138 138 138
Max. vent, length (ft) 57 N/A 50 N/A
Altitude height (ft) 10,200 10,200 10,200  
Noise (dB) 53 53 54 58
Weight (lbs) 33

Feature highlights

  • Flexible power and direct venting installation.
  • Modulating gas burner.
  • Electric ignition.
  • Temperature remote controller is included.
  • The AFR sensor (air-fuel mixture ratio) for proper gas combustion, increased efficiency, and low emission.
  • Other safety features include the overheat cutoff fuse, hi-limit switch exhaust, water temperature safety control, and freeze protection system.


Takagi provides a long warranty of 15 years on the heat exchanger and 5 years on other parts in residential applications.

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