Most are about the size of an average suitcase. The Takagi line ranges from less than two feet high by 14 inches wide, weighing 30 pounds; to 28 inches high by 19 inches wide weighing 90 pounds.

Although many heaters are currently working well without any water treatment, we recommend that homeowners in areas with hard water install a water softener or a de-scaling device in the water line before the heater. This should lengthen its lifespan as well as the time between servicing. In areas with exceptionally hard-water conditions, the heat exchanger inside the unit may require periodic flushing by a plumber to remove built-up scale. Keeping the temperature low also helps to prevent scale buildup in severe, hard-water conditions.

For the most accurate sizing, we recommend contacting your local Takagi sales office. But here are some general guidelines, concerning the Takagi line:

• Our smallest model, the T-K Jr. will simultaneously supply one shower and one appliance, such as a dishwasher or washer.


• The T-K3 can be installed in parallel with up to three other T-K3 units for added capacity.


• The T-M1 and T-H1 can handle four showers at once.

This product must be installed and serviced by a licensed plumber, a licensed gas fitter, or professional service technician. Improper installation and/or operation, or installation by an unqualified person, will void the warranty.

It can be installed anywhere with access to adequate combustion air and where the heater exhaust can be vented to the outdoors, it should not be installed outdoors if the home or business is located in a freezing climate. In a replacement situation, a tankless heater can usually go where the heater currently is located, although you may want to relocate the new unit to create more room or to achieve better venting options. Wherever you choose to locate the new tankless unit, always check for proper gas-line size. That's usually because the more powerful tankless models usually require larger gas lines than tanks.

You must use a dedicated, Category III approved stainless steel vent pipe for the entire exhaust run. You may not common-vent with any other appliance.

No. It still takes time to get the water to your faucets, just like it always has. Our heaters provide constant flow of hot water at the desired temperature. To get "instant" hot water, you need a recirculation pump.

Yes, you can use a Recirc pump, and it should be sized to provide enough flow to the heater; that is, 0.5 gallons per minute to 0.75 GPM, depending on the model. However, it should not be so big that it wastes energy and causes erosion of the system piping. We recommend aiming for 1 to 2 GPM of Recirc flow. If you are not familiar with pump sizing, please ask the pump dealer or Takagi for details.

The warranty is 10 years on the copper heat exchanger and five years on all of the other parts, except for fuses. Commercial warranties are three years on the heat exchanger and the parts.

There is a 24-hour website for basic troubleshooting and for submitting questions. Takagi also has a main office in Irvine, California, and branch offices throughout the country that may be called during business hours. Our plumbers are trained in the operation and repair of our units, and they can also contact Takagi for any additional help or for repair parts.

As of January 1, 2009, most of the units in the Takagi line qualify for up to a $1,500 income-tax credit. Please consult with your tax professional.

In general, at this time there are rebates for new construction installations only. Please consult with your local gas utility for details. There is a federal tax credit, however. See the question on "tax incentives" above.

We have found the average useful life to be 15 to 20 years, compared with 10 years or less for most tank-type models. In very hard water areas, water treatment is essential to long heater life.