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Sizing the unit properly is very important. Please consult with your local contractor for questions, concerns, or comments about sizing your tankless application.

Factors to Consider

Coldest Input Temperature: How cold does the water supply get in the winter? This factor, as well as output temperatures will determine the maximum output flow rate.
Set Point Temperature: The desired output temperature of the water, called the set point, is usually 122°F for residential use. It is also the default temperature of Takagi heaters. For higher-than-average output temperatures, the flow rate will decrease.
Flow Rate: This is the expected maximum rate of hot water flow of all fixtures at anticipated, peak-demand times. The top chart represents typical households with a standard 2.5 gpm shower/tub, bath sink, kitchen sink, dishwasher, and washing machine. For example, a T-K4/U or T-H3S would be recommended for a two bath home in cooler climates. If custom showers with body sprays or additional fixtures are present, add up the total flow rate of all the fixtures and consult the Flow Rate Guide below to choose the correctly sized heater. Consult local codes for additional sizing requirements.

Remember: Although a home with two or three bathrooms may only have one or two occupants currently, the number may increase if the family changes or the house is sold. Size for the house, rather than the number of occupants.

For more product information download the latest Takagi Product Guide.