Hot Water Cylinder Replacement: Repair or Replace?
Replace a hot water cylinder when the shell leaks, a sealed coil has failed or several worn parts together outweigh a new unit. If one bolt-on part has failed on a sound cylinder, repair it instead. The guides below follow that decision from the failed cylinder, not from the boiler.
Services
Each one starts with the diagnosis, so the price is known before any work.
No VAT is charged. There is no call-out fee.
What are you seeing?
Pick the nearest match and read the guide that answers it.
An old cylinderShould I repair or replace my hot water cylinder?
The test is whether the fault is in a part or in the vessel. Elements, thermostats, valves and vessels can be replaced. A seam that weeps, a base that has rotted through or a failed coil cannot be repaired. Start with a hot water cylinder diagnosis, then see cylinder fault repair for what a repair covers.
What decides the type and size of the replacement?
Vented or unvented, direct or indirect, and the volume all follow from the old cylinder, the water supply and the household. A like-for-like swap is the simplest where the old unit suited you. Unvented models need a competent installer and fall under Building Regulations Part G. The like-for-like sequence is on like-for-like cylinder replacement.
What does replacing a hot water cylinder cost?
A like-for-like cylinder replacement is a fixed price of £1,450 for labour and miscellaneous parts. A new cylinder installation is a fixed price of £2,400, including pipework, installation, commissioning and Building Regulations. No VAT is charged.
In both cases the cylinder is priced separately, from a price list by type, size and your preference, and we recommend the right one for your home. We cover London inside the M25, 24/7.
What does the replacement involve, and what is not a DIY job?
The old cylinder is isolated, drained and removed, then the new one is connected, filled, purged, set and rechecked. Isolating electrics, remaking pipework and commissioning the valve group and expansion devices are not householder jobs. Replacement cost guides are collected in the cylinder costs hub.
Take the cylinder apart
Guides on this topic
Questions people ask
How do I know if my cylinder needs replacing?
A leaking shell or seam, a failed sealed coil, or several worn parts at once. A single failed part on a sound cylinder is repaired.
How much does it cost to replace a hot water cylinder?
Replacement labour and miscellaneous parts are a fixed £1,450, and no VAT is charged. The cylinder is priced separately by type, size and your preference, and we recommend the right one.
Can I replace a hot water cylinder myself?
Not safely. It involves electrical isolation, remade pipework and, on unvented models, safety valves that need a competent installer.
Do I have to stay with the same type of cylinder?
No, but a like-for-like swap is simplest. Changing type affects pipework, supply pressure and regulation, which should be settled before a replacement is ordered.