Showers & Pumps

This category covers electric showers, the self-contained units that heat water as you use it. An electric shower takes a cold mains supply and heats it inside the unit, so it gives hot water whether or not the boiler is on, and it does not draw on a hot water cylinder.

Power rating and supply

Electric showers are rated in kilowatts, for example 8.5kW, 9.5kW or 10.5kW. A higher rating heats more water per minute, but needs a heavier cable and a larger circuit breaker: one maker specifies 6mm² cable on a 32A breaker for a 7.5kW model and 10mm² cable on a 45A breaker for 10.5kW. Check your existing cable size and breaker rating before choosing a replacement. The shower also needs a minimum mains pressure and flow; the same maker asks for at least 1 bar for 8.5kW and 1.5 bar for 10.5kW, so check your supply. If mains pressure is too low, a pumped electric shower fed from a gravity system may suit better.

Replacing an electric shower

Replacement models designed for easy fitting have several water and cable entry points on both sides, so they can line up with the existing pipe and cable positions. Compare the old unit's entry points and fixing positions with the new one.

Safety

In England, electrical work in a bathroom, including a new shower circuit, is notifiable under Part P of the Building Regulations. It must be done by a registered competent person or notified to building control. The water connection must be suitable under the Water Supply (Water Fittings) Regulations 1999.

For other options, see bathroom showers and shower pumps.