No. Cold water will automatically be refilled when hot water is running. The water level in the storage tank maintains at the same level at all time.
Only the showerhead that is supplied with the shower unit should be used. For safety reasons, showerhead helps releasing steam and pressure inside the tank under normal operating condition.
There are 5 built-in safety measures, including a thermostat, an overheating fuse, 2 temperature pressure release valves, and an anti-vacuum valve, which conform to the Electrical Products Safety Regulation.
It takes approximately 20-25 minutes, and the water heater will consume about 1 unit of electricity (around HK$1).
There is no difference in the amount of electricity consumption between the two types of water heater.
Given that the heating element of an electric water heater is entirely immersed, heat transfer is highly energy efficient. In general, electric water heater cost 15% less to run than other fuel-powered water heater does, thus it is more economical.
If 3-phase power is available (as in most new built village houses), an instantaneous 3 phase water heater would be a great choice. If the living flat is designed with single-phase power, a storage type water heater is more suitable.
Instantaneous water heater requires 3-phase power, which is not always available in every apartment. Most new built village houses are equipped with three-phase power, so 3-phase instantaneous water heater can be installed. However, the electricity supply design (single-phase or 3-phase) in an apartment depends on the decision of the developer.
Residents living in apartments with single-phase power can either choose to install a centralised electric water heater with a capacity of about 25-38 litres, or a shower storage type water heater with a capacity of 18 litres.