Electrodes or heating elements?

Electrodes or heating elements?
A steam generator can produce steam using heating elements (Keulertz, EOS) or electrodes (VAPAC).  

With heating elements, 1.3 kg of steam per hour is produced per 1 kWh of electricity; when using electrodes, this is 1.1 kg of steam per hour. 

Heating elements are therefore more efficient but can only be used in lime-free water, whereas a steam generator with electrodes actually requires lime to function. 

With steam generators featuring heating elements, the length of the elements is also important. The longer the elements, the larger the surface area in contact with the water.