Essential information is the temperature (degrees Fahrenheit) of the incoming water from the primary water source, temperature rise (incoming water temperature subtracted from 180°F [82°C]), the make and model of the dishwasher the Booster Water Heater will be used with OR the gallons per hour (GPH) (liters per hour [LPH]) required by the dishwasher for the final rinse cycle. The formula to figure kW of the Booster Water Heater needed to sanitize at 180°F (82°C) is: GPH x °F Temp Rise/400 = kW required (LPH x °Celsius Temp Rise/840 = kW required). Sizing charts are available in our price list and on our website.