How to Price Electric Shower Installation: Labour, Materials and Margin Guide

Quick Answer: Electric shower installation in the UK prices at £150-£300 for a like-for-like swap on an existing supply, £350-£700 where new electrical and water connections are run, and £600-£1,200+ where a new dedicated circuit must be installed from the consumer unit. The shower unit itself is £80-£350. A like-for-like swap is a single-trade job; a brand-new installation is a two-trade job (electrician for the notifiable circuit, plumber for the supply) — and that combination is the main cost driver. The circuit work is notifiable under Building Regulations Part P.

Summary

Electric showers are ubiquitous in UK housing because they give instant hot water independent of the boiler or cylinder — ideal for second bathrooms, en-suites, and homes with limited stored hot water. Pricing the work well hinges on one distinction: is this a like-for-like replacement on an existing, adequately rated supply, or a new installation requiring a dedicated high-current circuit? The two jobs differ by a factor of three or four in cost.

The critical technical fact is that electric showers are high-current loads. A modern 10.5kW shower draws around 45A; a 9.5kW unit around 41A. These need a dedicated radial circuit in suitably sized cable (typically 10mm²) with the correct protective device and a 30mA RCD, plus a pull-cord isolator. You cannot uprate an old 8.5kW shower to a 10.5kW one without checking — and usually upgrading — the cable, the breaker, and sometimes the incoming supply. This is where unqualified swaps go dangerously wrong.

This guide separates the unit, the electrical circuit (the expensive, notifiable part), the plumbing supply, the isolation and bathroom-zone compliance, and the making good. It explains the kW/cable matrix, the Part P obligation, and bathroom electrical zones. For related work see shower installation pricing guide, consumer unit replacement pricing guide and extra sockets and lights pricing guide.

Key Facts

Unit and material costs

Labour and ancillary costs

Regulatory and standards

Quick Reference Table

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Shower rating vs cable and protection (typical, subject to design)

Shower kW Current (≈) Cable (typical run) Protective Device
7.5kW 33A 6mm² 40A
8.5kW 37A 6-10mm² 40A
9.5kW 41A 10mm² 45A
10.5kW 46A 10mm² 50A*
11kW+ 48A+ 10-16mm² 50A+*

*Exact cable and breaker sizing must be designed per BS 7671 for the actual run length, installation method, and grouping — never assume. Voltage drop and current-carrying capacity govern.

Job-type pricing

Job Trades Typical Total
Like-for-like swap, same rating 1 (electrician) £150-£350
Swap with rating increase + cable upgrade 1-2 £350-£700
New install, dedicated circuit + supply 2 £600-£1,200
New install + CU upgrade/supply work 2 £1,000-£2,000+

Detailed Guidance

The cable and breaker matrix — the safety core

The number one electric-shower hazard is an under-rated circuit: a higher-kW shower fitted on cable and a breaker sized for a lower load, causing overheating. Cable and protective device must be sized for the shower's current draw, the cable run length (voltage drop), the installation method (clipped, in insulation, in conduit), and grouping with other cables. As a rule of thumb a 9.5-10.5kW shower needs 10mm² cable and a 45-50A device, but the actual design is the electrician's calculation under BS 7671 — the table above is indicative only.

When uprating an existing shower (say 8.5kW to 10.5kW), the electrician must verify the existing cable and breaker can carry the new load. Often they can't, and the cable must be re-run — which turns a "simple swap" into a circuit job. Quote the swap conditional on the existing circuit being adequate, with the re-run as a provisional sum.

Part P — the notifiable circuit

Installing a new dedicated shower circuit is notifiable work under Building Regulations Part P and must be carried out or certified by a registered competent person (NICEIC, NAPIT, ELECSA, etc.) who issues an Electrical Installation Certificate and Building Regulations Compliance Certificate. A genuine like-for-like replacement of the shower unit on an existing, adequate circuit is generally not notifiable (it's maintenance/replacement), but any new circuit, any consumer unit work, and any work that adds a circuit in a special location is. This is why a brand-new shower install is an electrician's job, not a plumber's.

Bathroom zones and RCD protection

Bathrooms are "special locations" under BS 7671 Section 701, divided into zones by proximity to the bath/shower:

All electric shower circuits must be 30mA RCD protected. The isolator is a ceiling-mounted 45A pull-cord (no wall switches within reach of the shower) and the supplementary bonding requirements of the location must be satisfied (often achieved automatically where all circuits are RCD-protected and main bonding is in place).

The plumbing side

Electric showers run off the cold mains (or a suitably pressured cold supply) — they heat the water on demand, so no hot feed is needed. The supply must deliver adequate flow and pressure; low-pressure gravity-fed systems may need a pump (£200-£500) for a satisfactory shower. A 15mm cold feed with an isolating valve to the shower is standard. Check the incoming pressure on survey — a 10.5kW shower on a feeble supply gives a disappointing trickle and a complaint.

Hidden costs and margin protection

The five most-missed lines: (1) cable re-run discovered when an uprate exceeds the existing circuit; (2) consumer unit way — many older boards are full, needing a Henley block or an RCBO addition; (3) supply adequacy — a 60A main feeding a shower plus cooker plus everything else may need a DNO upgrade; (4) tiling/making good around new fixings and cable chases; (5) pump for low-pressure systems. Apply a survey-first discipline: quote the swap firm, the circuit upgrade as a clearly stated extra.

Frequently Asked Questions

Can a plumber install an electric shower?

A plumber can connect the water and even physically mount the unit, but the electrical circuit — particularly any new dedicated circuit — is notifiable work under Part P and must be done or certified by a registered electrician. A like-for-like swap on an existing, adequate circuit can be a single competent person's job. A brand-new installation is properly a two-trade job: electrician for the notifiable circuit, plumber (or the electrician) for the water connection.

Can I just fit a more powerful shower on the existing cable?

Only if the existing cable and breaker are rated for the higher load — which often they are not. A jump from 8.5kW to 10.5kW raises the current from ~37A to ~46A and usually requires 10mm² cable and a larger protective device. Fitting a high-kW shower on under-rated cable is a fire risk. The electrician must verify (and usually upgrade) the circuit; quote the uprate conditional on this check.

Does an electric shower need its own circuit?

Yes — electric showers are high-current loads and require a dedicated radial circuit from the consumer unit, with 30mA RCD protection and a pull-cord isolator. They must never share a circuit with sockets or lights. The dedicated circuit is what makes a new installation notifiable under Part P.

Why might the shower be weak even though it's high-kW?

Electric showers heat water on demand, so a higher kW rating heats more water per second — but the flow is limited by the incoming cold mains pressure and the heating capacity. On a low-pressure or gravity-fed supply the shower may deliver only a trickle of hot water, especially in winter when the incoming water is colder. A booster pump or a check of mains pressure on survey prevents this complaint.

Regulations & Standards