That is the practical filter for a trade buyer: check what is actually feeding the property first, cylinder type, boiler type and measured pressure, before recommending either option. An electric shower sidesteps a weak or inconsistent hot water system by generating its own supply on demand. A mixer shower only performs as well as the system behind it allows, which makes it the stronger choice specifically where that system is already strong.
A higher kW-rated unit, 10.5kW against 8.5kW for example, has more headroom to maintain flow rate even as it works harder to raise the temperature, which is why higher-rated units tend to feel stronger and more consistent through the colder months. That headroom depends entirely on the property's electrical supply being able to support it: a higher kW shower draws more current, and the circuit and consumer unit need the capacity to match, which is not automatic on every property, particularly older ones.
Hard water carries dissolved calcium and magnesium, and neither mineral goes anywhere quietly. As water heats up, those minerals come out of solution and form limescale, a hard, chalky deposit that builds up wherever hot water sits or flows. The most obvious place it shows up is on immersion heaters and heating elements, where a coating of scale acts as insulation, forcing the element to work harder and longer to heat the same volume of water. Over time that means higher running costs and, eventually, elements that fail well before they should.
Read more from heating controls supplier.
An electric shower needs almost nothing from the existing hot water system, because it does not use it. It draws cold mains water and heats it instantaneously inside the unit itself, using its own dedicated electrical supply. That makes it the practical choice on properties with low or inconsistent water pressure, combination boiler systems where hot water competes with other demands, or any property where running a strong, consistent supply of pre-heated hot water to the shower simply is not realistic. Its performance depends on electrical capacity and incoming mains flow, not on the property's cylinder or boiler at all.
Plumb2U carries water softeners and the resin, salt and spare parts to keep them running, at trade prices with next-day despatch across the UK, whether the job is a first softener install or a service call on an existing one, for trade buyers from Epsom to anywhere else in the country.