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Hot Water Demand Calculator (GPM)
Design simultaneous hot water flow from editable fixture flows and a documented diversity factor, with the heat input it takes to hold it.
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Sizing calculators
Size tank gallons, tankless GPM, recovery time, and peak hot water demand for a household.
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Mixed Hot Water Capacity Calculator
Usable gallons at shower temperature from a hot tank: the per-gallon split, shower minutes, the equivalent tank at 120 F and the scald screen.
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Tankless Water Heater Size Calculator
Size simultaneous GPM and heat input so the coldest incoming water still gets hot, then screen the candidate unit's published rating.
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Water Heater BTU Calculator
Heat input a batch of water needs inside a time window, in nameplate BTU/hr, kW, amps and MBH.
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Water Heater Heat-Up Time Calculator
How long a tank takes to reach its thermostat setting from the temperature the water is at now, and the input needed to hit...
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Water Heater Recovery Rate Calculator
Recovery in gallons per hour at the rise you actually have, the recovery GPH at the 90 F rating basis, and an estimated first-hour...
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Water Heater Size Calculator (First-Hour Rating)
Size a tank from the hot water the fixtures draw in the busiest hour, then screen it against the nameplate first-hour rating.
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