An electric shower heats water on demand from the cold mains supply, making it independent of your boiler and hot water cylinder. It's a popular choice for UK homes — particularly as a second shower, or in properties with combi boilers where hot water flow rates can be an issue.
How Does an Electric Shower Work?
An electric shower passes cold mains water through a heating element inside the unit. Unlike power showers (which use hot water from your cylinder), an electric shower generates all its own heat. This means it always provides hot water — even when the boiler is off or the hot water tank is empty.
Electrical Requirements for an Electric Shower
Electric showers are high-current appliances. A typical 9.5kW or 10.5kW shower requires:
- A dedicated circuit from the consumer unit — no other appliances on the same circuit
- Cable sized for the load: typically 6mm² twin and earth for up to 40A
- A double-pole switch (pull-cord or wall switch) outside the bathroom zone
- An MCB (miniature circuit breaker) rated correctly for the circuit
- The circuit must be protected by a 30mA RCD
Consumer Unit Capacity
Your consumer unit needs a spare way for the shower circuit. If the board is full, an upgrade is required before the shower can be installed. Check with your electrician at quotation stage.
Shower Ratings — Choosing the Right Kilowattage
| Rating | Cold water performance |
|---|---|
| 7–8.5kW | Warm shower, weak flow |
| 9.5kW | Good performance, most common |
| 10.5kW | Better flow, useful in hard water areas |
Higher-rated showers heat water faster, giving better flow and temperature — but require appropriately rated wiring.
Part P Compliance
Installing an electric shower in a bathroom is notifiable work under Part P. It must be carried out by a registered electrician and certified on completion. Never ask a plumber to wire a shower unless they are also Part P registered.
How Long Does Installation Take?
A straightforward electric shower installation — where a circuit already exists and the shower is positioned near the consumer unit — takes around 2–3 hours. Longer cable runs or a consumer unit upgrade will add time.
Cost Guide
A typical electric shower installation costs £200–£400 for the electrical work (excluding the shower unit itself). Costs increase for longer cable runs, consumer unit upgrades or complex bathroom layouts.
Onyx Electrical Solutions installs electric showers across Greater Manchester. Call 07000 000000 for a free quote.