Water Heater & Hot Water Cylinder Services in Exmouth
Types of Hot Water System
Most Exmouth homes use one of these three hot water systems. Understanding yours helps you make the right repair or upgrade decision.
Vented Hot Water Cylinder
The traditional system found in many older Exmouth homes. A copper cylinder (usually in the airing cupboard) is fed by a cold water tank in the loft. Water is heated by the boiler via a coil inside the cylinder, or by an immersion heater as backup. Gravity feeds hot water to taps and showers.
Pros
- Simple, well-understood system — easy for any plumber to work on
- Low mains pressure is not a problem as the system runs on gravity
- Cheaper to install than unvented systems
- Immersion heater provides backup if the boiler fails
Cons
- Lower water pressure at taps and showers compared to unvented
- Cold water tank in the loft takes up space and can freeze in winter
- Slower to reheat once the hot water runs out
- Open system — water is exposed to air, which can cause corrosion over time
Unvented Hot Water Cylinder
A sealed cylinder connected directly to the mains water supply. No cold water tank needed in the loft. Water is heated by the boiler or an immersion heater and delivered at mains pressure, giving strong, consistent flow to all taps and showers simultaneously.
Pros
- Mains pressure hot water — strong, even flow at every outlet
- No cold water tank required — frees up loft space
- Sealed system reduces risk of contamination and corrosion
- Can supply multiple bathrooms at good pressure simultaneously
Cons
- More expensive to install (£1,500–£3,000 fitted)
- Must be installed and serviced by a G3-qualified engineer
- Requires adequate mains pressure — not suitable for all properties
- Annual service recommended to check safety valves and expansion vessel
Immersion Heater
An electric heating element fitted inside the cylinder — like a giant kettle element. Most cylinders have one as standard, either as the primary heat source or as a backup for when the boiler is off. Common in homes with Economy 7 tariffs where cheap overnight electricity heats water for the day.
Pros
- Independent of the boiler — works even if the boiler breaks down
- Can be set on a timer to heat water during off-peak electricity hours
- Relatively cheap to replace (£100–£200 fitted)
- Simple technology with few parts to fail
Cons
- Electricity costs roughly 4x more than gas per kWh
- Slower to heat a full cylinder than a gas boiler
- Element can fail due to limescale build-up — common in hard water areas
- Not economical as the sole heat source unless on a favourable tariff
Common Hot Water Problems
These are the most common hot water cylinder issues reported by homeowners in Exmouth and East Devon.
No hot water
The most common complaint. If the boiler is working but you have no hot water, the motorised valve (diverter or zone valve) that directs hot water to the cylinder may have failed. If you rely on an immersion heater, the element or thermostat may have gone. A plumber can diagnose this quickly.
Leaking cylinder
A leak from the cylinder body usually means internal corrosion has eaten through the copper. Small pinhole leaks can sometimes be patched temporarily, but a leaking cylinder generally needs replacing. Leaks from pipe connections or the immersion heater boss are often repairable.
Water too hot or not hot enough
The cylinder thermostat controls the temperature — it should be set to 60°C to kill Legionella bacteria. If the thermostat fails, water can overheat (a scalding risk) or stay lukewarm. Replacing the thermostat is a straightforward job costing £60 to £120.
Rumbling or banging noises
A rumbling cylinder often means heavy limescale build-up on the immersion heater element — the scale overheats and causes the water to bubble. Replacing the element usually stops the noise. Banging can also indicate a failing motorised valve or air in the system.
Hot water runs out too quickly
Either the cylinder is too small for your household, the thermostat is set too low, or the boiler is not heating the cylinder fully. A family of four typically needs a 150 to 210 litre cylinder. If yours is smaller, upgrading to a larger cylinder or switching to a combi boiler may be the answer.
Pressure relief valve dripping
On unvented cylinders, the temperature and pressure relief (TPR) valve discharges water if the pressure gets too high. Occasional dripping during heating is normal, but constant flow means the expansion vessel has lost its charge or the valve itself needs replacing. This is a safety-critical component — call a G3-qualified engineer.
Hot Water Cylinder Costs in Exmouth
Typical prices for hot water cylinder repairs, replacements and installations in the Exmouth area for 2026. For a full breakdown of plumbing rates, see our plumber costs guide, or get a tailored estimate with our cost calculator.
| Service | Typical Cost |
|---|---|
| Replace an immersion heater element | £100–£200 |
| Replace a cylinder thermostat | £60–£120 |
| Replace a motorised valve (2-port or 3-port) | £150–£300 |
| Replace a vented copper cylinder (like-for-like) | £400–£700 |
| Install an unvented cylinder (new installation) | £1,500–£3,000 |
| Replace an unvented cylinder (like-for-like) | £1,000–£2,000 |
| Annual unvented cylinder service | £80–£150 |
| Upgrade from vented to unvented system | £1,800–£3,500 |
Prices are estimates for 2026. Always get a written quote before work begins.
Hot Water Cylinder FAQs
Find a Hot Water Specialist in Exmouth
Browse our directory of local plumbers and heating engineers covering Exmouth and East Devon. Compare services, check qualifications and get in touch directly for a no-obligation quote.
Browse Local PlumbersNot sure whether to keep your cylinder or switch to a combi? Read our combi boiler vs cylinder comparison. Need your boiler looked at? See our boiler repair page. For urgent issues, visit our emergency plumber guide.