Why the result of the experiment does not match the calculations

      The power of the electric kettle is 2.5 kW. It was calculated that 1 liter of water from 20-100 degrees Celsius heats up in 2.23 minutes. On practical testing, 1 liter boiled in 4 minutes with an initial temperature of 20 degrees. Explain why the result of the experiment does not match the calculations!