What defines an instantaneous boiler system?

An instantaneous boiler system, also known as a tankless or on-demand water heater, is characterized by its ability to heat water only when needed. This feature eliminates the need for a storage tank, which means that the system heats water directly as it flows through the unit.

When a hot water tap is opened, cold water travels through the unit, where it is heated by either a gas burner or an electric element, delivering hot water immediately without any preheating or storage. This can lead to energy savings since the system does not spend energy keeping a tank of water hot at all times.

In contrast, options that mention continuous heating, stored hot water, or complex storage methods do not accurately reflect the operational principle of an instantaneous boiler. These descriptors align more closely with traditional water heater systems that rely on maintaining hot water supplies in tanks. Thus, the defining characteristic of instantaneity, which is heating only on demand, is what distinguishes this type of boiler system.