Takagi Tankless Water Heaters

Tankless water heaters listed in this category include a complete range of condensing and regular residential and commercial Takagi models for indoor or outdoor installation. Most of the Takagi tankless units include a remote temperature controller and a power cord (indoor models only). Select series have a built-in Easy-Link feature which allows to connect up to 4 heaters for high-volume hot water needs.

About Tankless Water Heaters by Takagi

A significant advantage of Takagi over other brands of tankless hot water heaters is their universal applicability. Besides typical domestic hot water heating application, these heaters can be used for baseboard/radiator heating, radiant floor heating and even snow melting applications. All Takagi units can be divided according to the fuel type (natural gas or propane), installation type (indoor or outdoor) and application (residential or commercial). The fuel type is denoted by the “-NG” or “-LP” at the end of the part#; indoor/outdoor installation type is denoted with “-IN” or “OS” suffix respectively.

Takagi tankless water heaters are packed with safety features such as freeze, overheat, and surge protection, and offer easy troubleshooting using the external temperature controller. Residential models T-H3 series are Energy Star rated.

Takagi offers a limited 12-year warranty for heat exchanger and 5-year warranty for parts on all residential models and 5-year/5-year for commercial.

Takagi Tankless Series

Takagi T-KJr2

The T-KJr2 series is the smallest water heater in Takagi line with an energy factor of 0.82, designed mostly for 1-2 bathroom applications. This series replaces the older Takagi Jr models.

Takagi T-K4

T-K4 heaters replace older Takagi T-K3 and T-K2 series and are capable of providing hot water in 2-3 bathrooms depending on the climate. Energy factor is 0.82.

Takagi T-D2

T-D2 series are a step above the T-K4 models, capable of delivering hot water for up to 4 bathrooms in warmer climate. They feature a commercial grade copper heat exchanger and Easy-Link connectivity. Energy factor is 0.82.

Takagi T-H3

T-H3J, T-H3S and T-H3 series are high-end condensing tankless water heaters with PVC venting capability, Easy-Link connectivity, Multi-Link compatibility (connect up to 20 units), commercial grade copper primary heat exchanger and 316L stainless steel secondary heat exchanger. The units boast an energy factor of 0.95 and have a hot water output similar to that of the T-KJr2, T-K4 and T-D2 respectively.

Takagi T-M32 and T-M50

T-M32 and T-M50 are NSF certified commercial water heaters with Easy-Link and Multi-Link features and a superior HRS35 copper alloy heat exchanger coil (C1220 alloy for ASME series).


For residential domestic hot water heating applications, there are several sizing options available. Brochure/Product Guide on each product page lists a model by model comparison with suggestions based on climate and number of bathrooms for easy selection. The second, more precise option, requires calculating hot water output of the unit in GPM (gallons per minute) using the temperature rise table (listed in the same file mentioned above). When unsure about the climate, use the second option or select a larger size model.
For commercial applications, always use the second option to calculate the total required hot water output in GPM based on the temperature rise (difference between municipal/ground water temperature and desired output temperature). For larger applications, several tankless units may be required.


All Takagi tankless water heaters, with exception of the T-H3 series (incl. T-H3J and T-H3S) require 4” size, Category III stainless steel venting (5” for commercial). All typical venting parts (pipes, elbows, collars, adapters, etc.) can be found on the Parts & Accessories page.
Takagi T-H3 series are condensing models which allow using Schedule 40 PVC, CPVC or PP pipe instead of the Cat. III.
The venting pipe sizes and maximum allowed pipe run are model-specific and are shown in the installation manual.
Air intake on all outdoor models is built-in. For indoor models, fresh air supply is taken from indoors by default. To convert to outdoor air intake, a TK-TV10 adapter is used. Given typical installation where water heater is mounted on an outside wall and vented though it, the best option for outdoor intake and exhaust is 2SVSHTC43S, for indoor air intake, 2ZVWB04.