Shorten a warm-water cleaning session
A resident cleans with warm running water at 5 L/min and compares eight minutes with six. The mixed stream is 25°C warmer than the inlet.
Open CalculatorInputs and calculation
| Tool input | Value |
|---|---|
| Currency | USD |
| Volume or billing unit | liters |
| Volume (L) | 40 |
| Temperature rise (°C) | 25 |
| Heating method | Electric resistance |
| Efficiency (%) | 100 |
| Energy price (USD per input kWh) | 0.3 |
| Water price (USD/L) | 0 |
Heat delivered = 40 × 25 × 0.001163 kWh. Divide by 1 to get about 1.163 input kWh. Multiply input energy by 0.3, add 40 × 0 for water, then round to USD 0.35.
Tool result · USD 0.35
| Tool input | Value |
|---|---|
| Currency | USD |
| Volume or billing unit | liters |
| Volume (L) | 30 |
| Temperature rise (°C) | 25 |
| Heating method | Electric resistance |
| Efficiency (%) | 100 |
| Energy price (USD per input kWh) | 0.3 |
| Water price (USD/L) | 0 |
Heat delivered = 30 × 25 × 0.001163 kWh. Divide by 1 to get about 0.8723 input kWh. Multiply input energy by 0.3, add 30 × 0 for water, then round to USD 0.26.
Tool result · USD 0.26
What the comparison shows
Two fewer minutes avoid 10 L and about 0.29 input kWh. If the tap stays off while scrubbing, use only the actual flow time.
Assumptions and limits
Use a mixed-water energy balance only if losses are negligible. The sample uses an illustrative efficiency for the whole heating process.
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