Before replacing an electric water heater, tell the installer whether the old one provided enough hot water and how the home is used now. The same capacity may be suitable, but a change in occupants or shower habits can change what you need. Have the mounting, pipework and electrical supply checked before ordering the replacement too.
Tell the installer how you use hot water
How many people shower, and how close together? Is the home used year-round or only for holidays? Those answers matter alongside capacity, reheating time and space.
If you're buying the unit yourself, agree compatibility and responsibility first. Saving on the purchase price is little help if it doesn't fit or the installer won't cover a problem with the supplied equipment.
The wall and the pipework need checking too
A filled cylinder is heavy. Have the mounting, wall condition, access, valves, pressure arrangements, safety discharge and electrical circuit assessed.
A corroded bracket, improvised socket or drain over a cupboard shouldn't be reproduced because that's how the old unit looked. Ask what needs correcting and have it included in the quote.
Compare the installed price
Include removal and proper disposal of the old heater, fittings, mounting, electrical work, testing, making good and IVA. Agree how unexpected wall or pipe damage will be priced before the old unit comes off the wall.
Know how to isolate it
Ask the installer to show you the water and electrical isolation points and explain the maintenance instructions. Keep the model, serial number and warranty information. Never block or disable a safety discharge to stop a drip; abnormal or persistent discharge needs checking.
Before you go ahead
- Demand and capacity checked
- Wall and access surveyed
- Electrical circuit assessed
- Discharge route safe
- Removal, invoice and warranty included
Common questions
Can I buy the heater and pay only for fitting?
You can ask, but agree responsibility for sizing, compatibility, transport, damage and warranty before purchase. A supplied unit may shift product risk to you.
Why does the safety valve drip?
Some discharge can relate to heating expansion, but continuous or abnormal flow needs diagnosis. Never block a safety discharge.
Sources and further reading
Official information checked on 12 October 2026. Rules and procedures can change; verify the live source for your exact circumstances.