Nearly every disappointing shower we are asked to look at was the wrong type for the water system it was connected to. The showroom rarely asks what is in your airing cupboard, and that is the single most important question. Work out your system, then choose.
Step one, identify your system
- Combi boiler. No cylinder, no loft tank. Mains pressure hot and cold, flow limited by the boiler's kilowatt output.
- Gravity fed. Hot water cylinder in the airing cupboard with a cold tank in the loft. Pressure depends on the height difference, so upstairs showers can be weak.
- Unvented cylinder. A tall insulated pressurised cylinder, no loft tank. Excellent mains pressure at multiple outlets.
Thermostatic mixer showers
The most common and generally the best choice. They blend stored or instantaneously heated hot water with cold and hold a stable temperature even when a tap is used elsewhere. On combi and unvented systems they perform superbly. On gravity systems performance depends entirely on head height, and a low pressure rated valve should be specified.
Mixers come as exposed bar valves, which are simple and easy to replace, or concealed valves built into the wall, which look tidier but need enough wall depth. In a solid brick terrace a concealed valve often means building a false wall, so raise it early. A dual outlet valve running a fixed head and a handset is the most practical family arrangement.
Electric showers
These take cold mains water and heat it as it flows through, using an internal element. Because heating happens instantly, flow is limited: an 8.5kW unit gives a modest flow, 9.5kW is better, and 10.5kW is what we normally fit where an electric shower is the right answer.
Their real strength is independence. They work when the boiler is off or broken, they cost nothing to run when not in use, and they suit a second shower room, a loft en suite far from the cylinder, or a household wanting a backup. They need a dedicated high current circuit, which is why fitting one is an electrical job as much as a plumbing one. In hard water areas the heating element scales over time, so a descaling routine extends its life.
Power showers
A mixer with an integral pump, or a separate pump feeding a mixer. This is the solution for a gravity system with poor pressure, and it can transform a weak shower into an excellent one. Pumps must be fed correctly, usually with a dedicated Essex flange or a Surrey flange take off from the cylinder to avoid drawing air. They are noisier than an unpumped shower and they use considerably more water, which matters if your cylinder is small.
Important: a pump must never be fitted to a combi or a mains fed supply. It is against water regulations and it will not work as intended.
Digital showers
A processor unit, sited in a loft, cupboard or under a bath, feeds a slim wall control. You get precise temperature to the degree, user presets, timers and often remote start from a control panel or app. Available in pumped and unpumped versions to suit any system. They are the most expensive option and the processor must be sited where it can be reached for servicing, but for households where several people want different settings they are genuinely useful.
Heads and outlets
- A 200mm to 250mm fixed head suits most systems. A 300mm head needs a strong flow to feel right.
- A handset alongside the fixed head makes cleaning and washing children far easier.
- Body jets need substantial flow, realistically only on an unvented system.
- A ceiling mounted head looks stunning but the pipework must be planned before ceilings close up.
- Check whether your chosen valve can genuinely run two outlets simultaneously or only divert between them.
Measure before you buy
At survey we measure static pressure in bar and flow rate in litres per minute at the nearest outlet. Those two numbers tell us exactly which showers will perform in your home and which will disappoint. It takes ten minutes and it prevents the most common and most annoying bathroom regret there is.
Get the right shower specified
Tell us what you want the shower to feel like and we will tell you what your system can actually deliver, then quote for it. Free survey, fixed written price within 24 hours, all plumbing and electrical work carried out in house by our own insured fitters.
Common questions
Which shower suits a combi boiler?
A thermostatic mixer shower. Combi systems provide mains pressure hot water, so a mixer performs well and a pump is neither needed nor permitted.
Are electric showers weak?
They deliver less water than a mixer because they heat it as it passes through, so a 10.5kW unit gives a modest but usable flow. Their advantage is hot water independent of the boiler.
When do I need a power shower?
Only on a gravity fed system with a cylinder and loft tank, where pressure is too low for a decent mixer performance.
What flow rate should I expect?
Around 8 to 12 litres per minute is a comfortable shower. Below 6 feels weak, and above 15 with a large head will empty a cylinder quickly.
Are digital showers worth it?
They give precise temperature control, presets and remote start, which some households love. The processor unit needs an accessible location for servicing.
Can two showers run at once?
On an unvented cylinder or a high output combi, usually yes. On a gravity system, rarely without a noticeable drop at both.