An electric shower is among the most powerful appliances in the home, heating cold mains water on the spot with an element of eight, nine or even ten and a half kilowatts. That enormous draw, used daily and often by several people, makes it look alarming on paper. But a shower lasts minutes, not hours, so the cost per shower turns out far gentler than the wattage suggests. This guide works out the real figures and where the bill actually comes from.
The short answer. An electric shower draws 8.5 to 10.5 kilowatts, but runs only minutes, so a typical 8-minute shower costs about 30p to 40p at the standard electricity rate of around 26p a unit. One person showering daily comes to roughly 120 pounds a year; a family of four nearer 480 pounds. The power rating is fixed, so the lever you control is time, and the eco or summer setting.
Huge power, short burst
The big number on an electric shower is its power, not its cost. Ten kilowatts is vast, more than three or four ovens at once, which is why electric showers need their own heavy circuit. But power is the rate energy is used, and the energy that actually costs you is the power multiplied by the time. Because a shower lasts a handful of minutes rather than hours, that big rate over a short burst comes to a modest amount of energy. A brisk shower costs pence; a long, daily one for everyone in the house adds up to a real line on the bill. The trap is reading the kilowatt figure as if it ran for an hour, when it runs for eight minutes.
What a shower actually costs
The sum is the one the running cost calculator does for any appliance: the power in kilowatts, times the hours it runs, times your unit rate. The table works it out for the common shower powers and a range of shower lengths, at the standard price-cap rate of about 26p per kWh, current in mid 2026. Find your shower's rating, usually marked on the unit, and read across.
| Shower power | 5-minute shower | 8-minute shower | 10-minute shower |
|---|---|---|---|
| 8.5 kW | ~18p | ~30p | ~37p |
| 9.5 kW | ~21p | ~33p | ~41p |
| 10.5 kW | ~23p | ~37p | ~46p |
At an example 26p per kWh. The figures show why time is the lever: the same 10.5 kW shower costs twice as much at ten minutes as at five. The power rating barely moves the cost compared with how long you stand under it.
What it adds up to for a household
One shower is cheap; the habit is what counts. A single person taking an 8-minute shower every day on a 9.5 kW unit spends about 33p a time, which is roughly 120 pounds over a year. Scale that to a household and it climbs fast: four people showering daily is closer to 480 pounds a year, making the shower one of the larger slices of the electricity bill. That is the figure worth knowing, because it is the one a few shorter showers a week visibly dents. Put your own shower's power and your family's habits through the calculator and you will see your real annual number rather than a guess.
Electric shower versus a gas mixer and a bath
Two fair comparisons put the cost in context. Against a gas-heated mixer shower, the electric shower has a catch: it heats with electricity at about 26p a unit, while a gas combi heats water at roughly 8p a unit of heat, as the hot water guide explains, so gas is the cheaper fuel per unit. Set against that, an electric shower heats only the water that flows through it, on demand, and often at a lower flow rate, so it wastes nothing standing in a tank. In practice the two can land closer than the fuel prices alone suggest, but a gas mixer usually costs a little less per equivalent shower. Against a bath, though, a reasonable electric shower wins comfortably: a bath uses a large volume of heated water, far more than a short shower, so the old advice to shower rather than bathe holds, as long as the shower stays brief. A long, luxurious shower can use as much as a bath, which is the point at which the advice breaks down.
Keeping the cost down
Because the power is fixed, time is the main lever, and it is a strong one: a five-minute shower costs little more than half what a ten-minute one does. A simple timer, or just not lingering, is the biggest saving available. Many electric showers also have a lower-power or eco setting, useful in summer when the incoming mains water is already warmer and needs less heating to reach temperature, so the element can run at reduced power; use it through the warmer months. Nudging the temperature setting down a touch reduces the draw as well. None of this is about cold, miserable showers, just brisk ones at a sensible heat.
Why a low-flow head is the wrong move here
One common saving does not apply to electric showers. Unlike a mixer shower, an electric shower controls its own flow as part of heating the water, so fitting a restrictive low-flow showerhead can interfere with how it works and even cause it to overheat and cut out. The water saving on a mixer comes from throttling the flow; on an electric shower the flow is already modest and managed by the unit. The saving here comes almost entirely from spending less time under it, not from changing the head. Keep showers brisk, use the eco setting when the weather allows, and a frighteningly high-wattage shower need not mean a frightening bill.
The bottom line
An electric shower's huge wattage is misleading, because it runs only for minutes: a typical 8-minute shower costs about 30p to 40p at the standard rate, and the cost scales almost entirely with how long you stay under it. One person showering daily is around 120 pounds a year and a family of four nearer 480, so the household total is where it matters. A gas mixer is usually a little cheaper to run and a bath usually dearer than a short shower. Shorten the shower, use the eco setting in summer, leave the showerhead alone, and the bill stays modest however big the number on the unit.