There are two types of shower in use today, the electric shower and the plumbed shower. The plumbed shower's water is taken directly from a preheated source such as central heating or hot water tank. A shower head allows hot and cold water to be mixed to the desired temperature.
The electric shower, or instantaneous shower as it is sometimes
known, enjoyed a large increase in popularity in many countries in the 1960's. With the ever increasing pace of life today, they are becoming even more popular, now often being found en-suite in the main bedroom of the house as well as in the bathroom.
The operation is very simple, in that a single cold water pipe enters the unit, the water being passed through a small cylinder inside the shower unit where it is heated instantaneously as it passes through. To achieve this a powerful element is required, often 7 or 8 kW (7 or 8 thousand Watts). The temperature of the water is controlled by a thermostat and care is taken with modern showers to prevent a drop in water pressure causing the temperature to increase rapidly, bringing the risk of scalding. A pressure switch senses the water pressure, so that if the pressure suddenly drops, (as can often be caused by someone turning on a cold tap elsewhere in the house), the temperature still remains constant. If the drop in pressure is too much the unit will switch off completely.
The advantage of the instantaneous shower over the plumbed type is that it can be used on the spur of the moment. The central heating does not need to be switched on and a ready supply of warm water is not required.
