Water Heater (Boiler) Volume Calculator
Estimate the ideal boiler volume for a household and how long it takes to heat the full tank.
How to Use the Water Heater (Boiler) Volume Calculator
- Enter the number of people in the household.
- Enter the expected hot water use per person (default 50 L).
- Enter cold and target temperatures.
- Enter the heater power in kW.
- Click Calculate to see volume and heating time.
Casos de Uso
- •Choosing a domestic water heater.
- •Sizing a hotel bathroom boiler.
- •Planning off-grid hot-water systems.
Fórmula
Volume = persons × daily hot water per person. Heating time (min) ≈ (volume × ΔT × 4.2) / (power × 60), where 4.2 kJ/kg·°C is water specific heat.
Preguntas Frecuentes
How much hot water does one person use?
A realistic budget is 30–50 L for light use (showers only) and 60–100 L for heavy use (baths, laundry, dishwashing). Use 50 L as a default.
Why round up to the next 10 L?
Boilers are sold in discrete sizes. Rounding up ensures you never run out; if cost is critical, round down accepting shorter hot-water reserves.
Why specific heat 4.2?
Water needs 4.186 kJ to raise 1 kg by 1 °C. Rounded to 4.2 for everyday calculations.