On 30-Mar-2004, "News" wrote:

Tankless take up far less space than a large cylinder, one its main
advantages. I have seen these used in commercial kitchen on faucets where
they are on for the best part of an hour. They can deliver 12 litres per
minute continuously and never run out. That is 720 litres per hour (190.2
US gallons per hour) running out of the tap. 190 gallons? that is quite a
size of storage cylinder you would need when a small white box on the wall
does it without taking up all that space.

Agreed. That is the primary advantage of tankless heaters.

What I disagree with is the assertion made by others that they save significant
money over a tank heater.