Electric shower running cold water only
Check the steps below first — if you're not confident, get it fixed safely today.
Post a job — we'll find you an engineer →⚠️ Any electrical work on shower units must comply with Part P Building Regulations. Internal repairs to electric showers should be carried out by a qualified electrician or approved plumber. Always isolate the electricity supply before opening a shower unit.
An electric shower that runs cold is one of the most frustrating household problems — and it usually strikes when you need a hot wash most. The good news is that electric showers are relatively straightforward units, and nine times out of ten the fault is either a tripped safety device, a loss of power, or a failed heating element. Cold-water-only faults are common in older units, after power cuts, or when the shower has been in heavy use. This guide walks through the logical checks you can do yourself — from verifying the isolator switch to testing the cold water supply — before deciding whether a repair or replacement makes sense. If you're not confident working with electrical components, or if the fault persists after these checks, it's time to call a qualified Part P-registered electrician.
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Most likely cause & what to check
Check the isolator switch — there should be a dedicated double-pole isolator switch outside the bathroom or in the consumer unit. Confirm it is in the ON position.
Check your consumer unit (fuse box) for a tripped RCD or MCB on the shower circuit. Reset if tripped.
If power is confirmed: most electric showers have a thermal cut-out that trips when the unit overheats. Locate the small reset button on the shower unit (refer to your model's manual) — some require removing the cover to access it.
Check the cold water supply — electric showers are fed from the mains cold supply. If there is no cold water to the shower, the unit will not operate. Check the isolation valve on the supply pipe.
If the unit powers on but produces no heat, the heating element has likely failed. A replacement element costs £15–£50 but electrical installation work must be done by a Part P-registered electrician.
If the unit is over 8–10 years old, a complete replacement shower unit (£80–£200) may be more economical than a repair.
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Frequently asked questions
Why is my electric shower suddenly running cold?
The most common causes are a tripped RCD or MCB in your consumer unit, a thermal cut-out triggered by overheating, a loss of cold water supply, or a failed heating element inside the unit. Start by checking the isolator switch and your fuse box before investigating the shower itself.
Can I repair an electric shower myself?
Basic checks like resetting a thermal cut-out or checking isolation valves are fine, but any work involving opening the unit or replacing electrical components must be done by a qualified electrician under Part P Building Regulations. This protects you legally and ensures safety.
How much does it cost to replace an electric shower heating element?
A replacement element itself costs between £15 and £50, but you'll need to pay a qualified electrician for installation, which typically adds £100–£200 to the bill. For older showers, it's often more cost-effective to replace the whole unit.
Is it safe to use an electric shower that's tripped its thermal cut-out?
The thermal cut-out is a safety feature designed to prevent overheating and potential hazards, so no — don't ignore it. If it keeps tripping, there's an underlying problem that needs professional diagnosis rather than repeated resets.
What should I do if my electric shower has no power at all?
First, check the dedicated isolator switch (usually outside the bathroom) is switched on, then inspect your consumer unit for a tripped RCD or MCB on the shower circuit and reset it if needed. If power still hasn't returned, contact a qualified electrician to investigate a potential fault in the wiring.
How old should an electric shower be before I consider replacing it?
Most electric showers last 8–10 years with normal use before components start to fail. If yours is past this age and the heating element has gone, replacement is usually more economical than repair — newer models are also more energy-efficient.