UTELVANI
Fictional worked example

Convert two shower routines into monthly heated volume

Two people each draw an estimated 25 L from the hot supply each day. Over 30 days that is 1,500 L. If they are away for six days of the same 30-day period, the 24 occupied days require 1,200 L.

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Inputs and calculation

30 occupied days
Tool inputValue
CurrencyUSD
Volume or billing unitliters
Volume (L)1500
Temperature rise (°C)35
Heating methodElectric resistance
Efficiency (%)100
Energy price (USD per input kWh)0.25
Water price (USD/L)0.003

Heat delivered = 1500 × 35 × 0.001163 kWh. Divide by 1 to get about 61.0575 input kWh. Multiply input energy by 0.25, add 1500 × 0.003 for water, then round to USD 19.76.

Tool result · USD 19.76

24 occupied days
Tool inputValue
CurrencyUSD
Volume or billing unitliters
Volume (L)1200
Temperature rise (°C)35
Heating methodElectric resistance
Efficiency (%)100
Energy price (USD per input kWh)0.25
Water price (USD/L)0.003

Heat delivered = 1200 × 35 × 0.001163 kWh. Divide by 1 to get about 48.846 input kWh. Multiply input energy by 0.25, add 1200 × 0.003 for water, then round to USD 15.81.

Tool result · USD 15.81

What the comparison shows

Six unoccupied days avoid 300 L and about 12.21 input kWh in this usage model. Some tank energy can continue without any draw.

Assumptions and limits

The estimate assumes the same inlet, heater and price on occupied days. It does not include energy used while away to keep a tank hot.

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