Electric Shower Installation: What It Involves in the UK
What fitting an electric shower involves in a UK home, from dedicated circuit and consumer unit checks to cost, notifiable work and choosing a kilowatt rating.
An electric shower heats water as you use it, so it needs no hot water tank and can give a strong shower from a cold supply. It also draws a lot of power, which is why installation is more than hanging a unit on the wall. This guide explains the principles, typical costs and what you should expect from the person doing the work.
Why a shower needs its own circuit
Electric showers are among the highest-load fixed appliances in a home. They are normally supplied by a dedicated circuit with its own protective device at the consumer unit, a suitably sized cable and a switch in an approved location. They should not be fed from an ordinary socket circuit.
The size of the circuit depends on the shower's rating, commonly quoted in kilowatts. A higher rating gives more heat but needs a heavier cable and a supply that can support it. The existing consumer unit may have no spare capacity, or lack the right protection, which is a frequent cause of extra cost. See the cost of replacing a consumer unit if that applies.
What the job usually includes
- Checking the consumer unit, supply and cable route.
- Fitting a dedicated protective device and, if needed, upgrading the unit.
- Running new cable to the bathroom, often through walls or ceilings.
- Fitting a ceiling-mounted isolating switch, as required in bathrooms.
- Making plumbing connections to the cold supply and waste.
- Making the electrical connections and securing the unit.
- Testing, certification and notification of the work.
Often an electrician and a plumber are both needed, unless one person is competent in both. Ask who is responsible for each part and the final test.
Is it notifiable?
Installing a new circuit, or work in a bathroom, is typically notifiable in England. That means it should be done by an electrician registered with a competent person scheme, or be inspected through building control. See bathroom electrical zones explained for why bathrooms get extra rules, and which electrical work needs a registered electrician for the broader picture.
Typical costs
A like-for-like swap of an existing electric shower often costs somewhere around £150 to £350 in labour. A first-time installation involving a new circuit, cable runs and consumer unit work typically costs more, commonly in the range of several hundred pounds plus the unit. Regional variation applies, with London and the South East typically higher. The shower itself is separate.
Choosing a shower
- Power rating. A higher kilowatt rating gives a hotter, stronger flow in winter, but needs a bigger circuit.
- Water pressure. Electric showers work on mains pressure and suit lower-pressure properties, but flow rate varies with the incoming supply.
- Temperature stability. Look at features that keep the temperature steady when someone runs a tap.
- Ease of cleaning and accessibility. Controls that are easy to read and use suit all ages.
Aftercare and safety
Keep the enclosure and any filter clean, as limescale can reduce flow and heating performance. Never use a shower that is cracked or leaking. If it trips the supply or smells hot, switch it off at the isolating switch and call an electrician. Do not remove the cover of the unit to attempt repairs.
A worked example
A household replaces an old 8.5 kW electric shower with a newer 9.5 kW model, assuming it is a quick swap. The electrician checks the cable size and protective device and finds the existing circuit is suitable for the old rating but marginal for the new one. The options are to choose a unit with the same rating as the old one, or to upgrade the cable and protective device. The homeowner picks a shower with a rating the circuit can support, which saves a significant cost. Checking before buying is the key point. Ratings and figures here are illustrative and each installation differs.
Questions to ask before ordering a shower
- What is the rating of the existing circuit, and can it carry a bigger unit?
- Is the water pressure suitable for the model?
- Where will the isolating switch go?
- Who will do the plumbing, and who is responsible for the final test?
- Is the cable run accessible, or will walls and ceilings need opening up?
Common mistakes
- Buying a higher-rated shower before checking the circuit.
- Installing on a fused spur or ordinary socket circuit.
- Skipping the isolating switch or fitting it in the wrong place.
- Not flushing the pipework before connection, so debris blocks the unit.
- Forgetting to leave the installation certificate with the household paperwork.
Edge cases
- Flats: shared water supplies and building rules may affect where cable runs can go.
- Rented homes: only the landlord should arrange a new shower circuit.
- Older homes: wiring or consumer units may need upgrading first.
- Tiled walls: drilling through tiles needs care, as does sealing around fixings.
When to call a professional
Electric showers should be installed by a registered electrician. Before any visual check, switch off at the isolating switch and the consumer unit. If you see water around the electrical parts, or the unit trips the supply, stop using the shower until it has been checked.
Frequently asked questions
Can I replace an electric shower with a higher-powered one?
Often not without checking the circuit. A more powerful unit may need a bigger cable and protective device. An electrician must assess it first.
Does an electric shower need to be earthed?
Yes. Proper earthing and bonding are an essential part of the installation, and the installation should be tested afterwards.
How long does installation take?
A like-for-like swap is often a couple of hours. A new circuit, with cable runs and plumbing, may take most of a day or more.
Is an electric shower more efficient than a mixer shower?
An electric shower heats only the water you use, so there is little standing loss, but it draws high power while running. Efficiency compared with a mixer shower depends on your boiler, tank and habits, so it is worth comparing with your own bills.