Cost guide
How much do hot water cylinders cost?
An unvented cylinder installation costs £1,800 to £3,500 fitted. Replacing a vented cylinder like for like is £700 to £1,400, and an immersion heater change is £150 to £300.
Typical prices
Ranges, not quotes. A quote depends on your home and the job.
| Work | Typical UK price |
|---|---|
| Unvented cylinder, supply and fit | £1,800 to £3,500 |
| Vented cylinder replacement | £700 to £1,400 |
| Immersion heater and thermostat | £150 to £300 |
| Annual unvented cylinder service | £90 to £160 |
| Expansion vessel replacement | £180 to £350 |
| Cylinder with heat pump coil, supply and fit | £2,200 to £4,000 |
Ask to see the G3 qualification, which is separate from Gas Safe registration. The law requires it for unvented cylinder work, and it is what allows the installation to be notified to building control.
What moves the price
- Unvented against vented. Unvented needs G3 certified installation, a discharge route and building control notification.
- Cylinder size and whether it carries one coil or two.
- Whether a loft tank and vent pipework are being removed.
- The discharge pipe run to a safe visible termination outside.
- Whether the incoming main can supply the flow rate an unvented cylinder needs.
- A heat pump coil, which costs more now and saves a cylinder change later.
What the money buys: unvented cylinder installation and g3 certification.
Who quotes for it
885 of the 7,519 plumbers and heating engineers listed on this site take on hot water cylinders.
The towns where most are based: Bristol (10), Nottingham (9), Glasgow (8), Aylesbury (8), Manchester (7).
Questions about hot water cylinders
What size cylinder do I need?
Roughly 150 litres for one bathroom, 210 litres or more for two in simultaneous use. A cylinder fed by a heat pump needs a larger coil than one fed by a boiler.
Can I keep my immersion heater as a backup?
Yes, and it is worth doing. Most cylinders take one or two immersion heaters, and they cover a boiler breakdown in the middle of winter.