Electric shower or mixer shower — what changes electrically?
How the shower type you choose changes the electrical work needed, from a dedicated 40A circuit to a simple pump spur.
The plumbing decision usually gets made first, then someone asks the electrician whether it is possible. It nearly always is — but the cost difference between the two options is significant and worth knowing before you commit.
An electric shower heats water itself and needs one of the heaviest circuits in the house. A mixer takes hot water from the system and may need nothing electrical at all, or just a supply for a pump.
- Electric shower: dedicated high-current circuit, isolator, board capacity
- Mixer: often no new circuit; pumped versions need a fused supply
- Board age and spare ways often decide the true cost
- Both require zone-compliant installation and RCD protection
The electric shower circuit
A dedicated way at the board, correctly sized cable for the run, a ceiling pull-cord or outside-the-room isolator, and RCD protection. If the board is full or is an older rewireable unit, that work comes first — which is where most of the cost difference sits.
Mixer showers and pumps
A gravity-fed system with a pump needs a fused spur in a suitable location, usually in an airing cupboard or under the bath with access. A mains-pressure system frequently needs nothing at all.
Which is cheaper overall
Electrically, mixer wins almost every time. Whether that holds overall depends on your hot water system — an electric shower still works when the boiler is off, which has its own value in some households.
Common questions
Can I swap an electric shower for a mixer?
Yes — the redundant circuit is safely decommissioned or repurposed, and the certificate updated.
Does a mixer shower need any electrics?
Only if pumped or if it has electronic controls.
Is the isolator switch required?
Yes, a means of isolation is required and must be sited appropriately for a bathroom.
Get a fixed price
Still deciding? Send a photo of your board and tell us the hot water system — we'll price both routes so the decision is informed.