3 calculators in this category
- Water Heater Recovery Rate CalculatorSensible heat method, 8.33 BTU per gallon per FRecovery rate is how fast a storage water heater replaces what you have drawn off, in gallons per hour at a stated temperature…
- Water Heater Size Calculator (First Hour Rating)DOE first hour rating methodA storage water heater is sized on one hour, not one day: the busiest hour the household ever puts it through. Add up the hot…
- Tankless Water Heater Sizing CalculatorASHRAE service water heating methodA tankless water heater has no reserve to fall back on, so it is sized on two numbers and nothing else: the gallons per minute…
Which one do you need?
- Water Heater Recovery Rate Calculator
- Convert burner BTU/hr or element kW into gallons per hour of recovery at your temperature rise, with tank reheat time and the input a target GPH would need.
- Water Heater Size Calculator (First Hour Rating)
- Size a storage water heater by adding up peak-hour hot water use and matching it to first hour rating: usable storage plus recovery. Gas and electric.
- Tankless Water Heater Sizing Calculator
- Size a tankless water heater from simultaneous fixture flow and the rise from groundwater to setpoint. Returns required GPM, BTU/hr, kW and unit headroom.