Sizing the unit properly is very important. Please consult with your Regional Takagi office for questions, concerns, or comments about sizing your tankless application. Or contact our corporate headquarters at 949.770.7171 and we would be more than happy to assist you!

Light Residential Usage:

A typical scenario would involve two people living in a small home, condominium or apartment with one bathroom and possibly a dishwasher and a washing machine. The T-K Jr. will supply enough hot water to run both the shower and one of those appliances simultaneously – unless the incoming water is almost freezing. In that case, the homeowner may have to run only one fixture at a time.

Standard Residential Usage:

If five people are living in a mid-sized home (for example, two parents, working full-time, and three teenagers), two showers and a sink or a washer will likely be operating simultaneously each weekday; i.e. in the morning when everyone is getting ready for work or school. For this type of family, the T-K3 are recommended, but only if showers are low-flow (2.0 to 2.5 GPM) and incoming water temperatures are about 50°F or higher. For very cold water temperatures, such as 60°F or higher, two showers and one appliance can be used at the same time with no problems.

Heavy Residential or Commercial Usage:

This category describes larger homes with three or more showers used simultaneously. It would also include a single master bath, featuring a shower with multiple heads or body sprays. Here, you must determine the exact maximum flow rate, using the flow chart for the T-K3, T-M32, T-M50, or the T-H2-DV, T-H2-OS. The chart will tell you which unit is best for the application and possibly how many of them you will need.
Generally, the T-M32 and the T-H2-DV will supply three to four showers at once, depending on the incoming water temperature. If a higher flow is required, multiple T-M32, T-M50,T-K3 or T-H2-DV, T-H2-OS units will provide the solution. To determine the precise number

“How do I choose which Takagi to use?”

Here is a brief rundown on the four most powerful units in the Takagi line, to help you select the right one for a larger application:

T-K3: Relatively small…easy installation with no TM-RE20 multi-unit controller…connect up to four units per application…convertible to direct vent. T-M32: Higher maximum flow rate than the T-K3…connect up to 20 units with the MC01…convertible to direct vent. T-M50: Highest BTU/hr rating and output at widest range of ?T of all Takagi heaters. T-H2: Most efficient heater at 92% to 95%...at 199,000 BTU per hour, it has a flow rate same as the T-M32.

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. A home may have three or four showers, but will they be used at the same time? If not, a mid-sized heater may work. If they will be used at once – or if several other appliances will be used while one or more showers are running – consider upgrading. T-H2: Most efficient heater at 92% to 95%...at 199,000 BTU per hour, it has a flow rate close to the T-M1.