Heating 100 liters for a family
A five-person family estimates a combined 100 L of heated water for a busy day. Its sample heater delivers water at 50°C from a 15°C inlet.
Open CalculatorInputs and calculation
| Tool input | Value |
|---|---|
| Currency | USD |
| Volume or billing unit | liters |
| Volume (L) | 100 |
| Temperature rise (°C) | 35 |
| Heating method | Electric resistance |
| Efficiency (%) | 90 |
| Energy price (USD per input kWh) | 0.25 |
| Water price (USD/L) | 0.003 |
Heat delivered = 100 × 35 × 0.001163 kWh. Divide by 0.9 to get about 4.5228 input kWh. Multiply input energy by 0.25, add 100 × 0.003 for water, then round to USD 1.43.
Tool result · USD 1.43
| Tool input | Value |
|---|---|
| Currency | USD |
| Volume or billing unit | liters |
| Volume (L) | 80 |
| Temperature rise (°C) | 35 |
| Heating method | Electric resistance |
| Efficiency (%) | 90 |
| Energy price (USD per input kWh) | 0.25 |
| Water price (USD/L) | 0.003 |
Heat delivered = 80 × 35 × 0.001163 kWh. Divide by 0.9 to get about 3.6182 input kWh. Multiply input energy by 0.25, add 80 × 0.003 for water, then round to USD 1.14.
Tool result · USD 1.14
What the comparison shows
The smaller volume reduces both the heating input and the water charge by 20% before rounding. The USD 0.29 displayed difference is per modeled day.
Assumptions and limits
Use total heated water only. Mixed fixture water can include cold water that never passes through the heater.
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