Independent energy/ CALCULATOR
Usable hot-water storage
Estimate the mixed-water volume, shower time and stored heat available from a hot-water tank.
Use the heated water volume available before the draw, not automatically the nameplate volume.
Use a realistic average tank temperature; stratified tanks are not uniform.
Seasonal mains or well-water temperature can change the available mixed volume.
Use the temperature after the mixing valve or at the outlet for this scenario.
Measure with a container and timer when possible.
Use water-running time, not total bathroom occupancy.
Hot water in the delivered mix
67 %
Ideal mixed-water volume
225 L
Equivalent continuous shower time
28.1 min
Equivalent typical showers
3.5 showers
Heat stored above incoming cold water
7.8 kWh
Perfect mixing at constant temperatures, the full stated tank volume initially at one temperature, water at 1 kg/L and 4.186 kJ/(kg·K), and no reheating during the draw. Tank stratification, thermostat deadband, usable outlet position, pipe loss, simultaneous taps, heater recovery, mixing-valve limits and safety requirements are excluded. Actual usable volume can be lower.