Free · Personal hygiene calculators 🧼

Shower Water & Heating Cost Model Calculator

Estimate daily water use and running costs with an explicit fixed heating-energy factor.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Edit a calculated value to solve backwards, or lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

Two people each taking one ten-minute shower daily at 6 L/min use 120 litres per day. At 2 per m³ of water and 0.15 per kWh, with the fixed 0.029 kWh/L heating factor, each shower costs 0.381. The annual-rate display uses 365.25 days and totals 278.3205.

Water per shower = minutes × litres per minute; cost = water × [water price per litre + 0.029 × energy price per kWh]

Worked example

Enter these known values and leave the other values blank.

People in household
2
Average shower duration
10 min
Showers per person
1 /day
Flow rate per minute
6 L /min
Water price
2 USD / m³
Energy price
0.15 USD /kWh
Daily water use
120 L /day
Single shower cost
0.38 USD
Total water cost
87.66 USD / yrs
Total energy cost
190.66 USD / yrs
Total shower cost
278.32 USD / yrs

Assumptions and limitations

  • This version uses a fixed 0.029 kWh per litre heating assumption. It does not model a specific temperature rise, heater efficiency, pipe losses, heat-pump performance or changing utility rates. Annual-rate units use a 365.25-day year; a calendar-year bill may differ.
  • Match the units shown and use measured inputs where available. The result follows the stated model and does not account for unentered changes.

Common questions

Can I change heater efficiency or the water-temperature rise?

This version uses a fixed 0.029 kWh per litre heating assumption. It does not model a specific temperature rise, heater efficiency, pipe losses, heat-pump performance or changing utility rates. Annual-rate units use a 365.25-day year; a calendar-year bill may differ.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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