How to Calculate Time to Heat Water

How to Calculate Time to Heat Water
••• Toa55/iStock/GettyImages

Using the formula Pt = (4.2 × L × T ) ÷ 3600 you can calculate the time it takes to heat a specific quantity of water from one temperature to another temperature. Once you have calculated the thermal power used to heat the water, as represented by Pt in the above equation, divide this number by the heater element rating to find out how long it would take to heat your water.

Calculate Kilowatt-Hours

Calculate the kilowatt-hours (kWh) required to heat the water using the following formula: Pt = (4.2 × L × T ) ÷ 3600. Pt is the power used to heat the water, in kWh. L is the number of liters of water that is being heated and T is the difference in temperature from what you started with, listed in degrees Celsius.

Solve for Thermal Power

Substitute in the appropriate numbers into the equation. So imagine you are heating 20 liters of water from 20 degrees to 100 degrees. Your formula would then look like this: Pt = (4.2 × 20 × (100-20)) ÷ 3600, or Pt = 1.867

Divide by Heater Element Rating

Calculate the amount of time it takes to heat the water by dividing the power used to heat the water, which was determined to be 1.867 with the heater element rating, listed in kW. So if your heater element rating was 3.6 kW, your equation would look like this: heating time = 1.867 ÷ 3.6, or heating time =0.52 hours. Therefore, it would take 0.52 hours to heat 20 liters of water, with an element with a rating of 3.6 kW.

Related Articles

How to Calculate Temperature From BTU
How to Calculate Tons of Cooling for a Cooling Tower
How to Convert From BTU to Fahrenheit
How to Calculate BTU for Heat
How to Calculate Heat of Sublimation
How to Calculate Boiler Heat Input Rate
How to Calculate Molar Heat Capacity
How to Convert Joules to Kelvin
How to Convert BTU to KW
How to Convert HVAC Tons to Amps
How to Calculate the Time to Heat an Object
How to Convert Horsepower to kWh
How to Calculate a Calorific Value
Conversion of Cubic Feet Per Hour to BTUs
How is Wattage Calculated?
How to Calculate a Final Temperature
How to Calculate Heat Flux
How to Test a Resistance Temperature Detector
How to Calculate Joules of Heat
How to Find the Molar Heat of a Combustion Candle