Independent energy/ CALCULATOR
Hot-water tank recovery time
Estimate the energy, cost and ideal time needed to heat a stored volume between two temperatures.
Use the volume that actually needs reheating, not automatically the tank nameplate volume.
Use a realistic inlet or mixed tank temperature for the scenario.
Energy arithmetic does not determine a safe storage or delivery temperature.
Use sustained input available to water heating, after any power limiting or staging.
Useful heat entering the water divided by purchased energy during recovery.
Use your all-in energy price in any currency; the result uses the same currency.
Temperature rise
45.0 °C
Heat delivered to water
7.85 kWh
Required input energy
8.26 kWh
Energy cost per full recovery
1.65 currency
Ideal recovery time
2.75 h
Ideal recovery time
165 min
Equivalent recovery rate
54.5 L/h
Interpretation:With no hot-water draw during recovery, the ideal heating time is about 2.75 hours. Verify the product recovery rating and available electrical power.
Uniform water temperature, constant heat capacity, constant input power, stated efficiency and a flat energy price. Tank stratification, thermostat deadband, heating-element staging, draw-off during recovery, pipe losses, standby loss and fixed tariff charges are excluded. Product recovery ratings and safe-temperature requirements govern final selection.