What is the difference between an electric, mixer and power shower?

They differ in where the hot water comes from and what provides the pressure — and choosing the wrong type for your plumbing is the commonest cause of a disappointing shower.

Electric shower. Takes cold water only and heats it instantly with an element as it passes through. Independent of your hot water system, so it works when the boiler is off or the cylinder is empty — which is why it suits a second bathroom, a guest room or a household with high hot water demand. Its flow rate is limited by physics: heating water instantly takes a lot of power, so a higher kilowatt rating gives more flow, and in winter the incoming water is colder so the flow drops noticeably. This is why electric showers feel weaker in January.

Mixer shower. Blends existing hot and cold water. Flow and pressure come from whatever supplies the house, so it is only as good as your plumbing — excellent on a combi boiler or mains-pressure cylinder, and weak on a gravity-fed system where the cold tank sits only a little above the bathroom.

Power shower. A mixer with a built-in pump. It exists specifically to solve the gravity-fed problem, and it is only appropriate on a gravity-fed system — you must not fit a pump to a mains-pressure or combi supply, which is both ineffective and generally prohibited by water regulations.

What actually determines a good shower: the flow rate in litres per minute rather than any marketing term, and adequate pressure. Measure yours by timing how long a container takes to fill.

Thermostatic is a separate and important feature on any type: it holds temperature when another tap is used, and is a safety requirement in many settings because it prevents scalding.

Practical points: electric showers need their own high-current circuit and cannot simply replace a mixer; pumps must be installed with correct pipework and are noisy; and in hard water areas, limescale is the main cause of failure in all three.