The immersion heater is inside the hot water cylinder and involves heating the water using an electric heating element housed inside the hot water cylinder. The immersion heater works similarly to a kettle, relying on a metal coil that heats the water surrounding it. The immersion heater is electric, powered to electricity and can be operated through a timer to heat water at specific times of day. Some cylinders may have two immersion heaters, a top and bottom heater. The top immersion heater works when you press the Booster button to heat water quickly in a few minutes rather than needing 1 or more hours.

Common issues with an immersion heater?

A good indication that the heating element in your immersion heater may not be working correctly is if you turn on the hot tap and you are not getting much hot water, or you are waiting a very long time for the hot water to heat up.

Common issues with an immersion heater can be;

Circuit breaker may have tripped
If the power supply to the immersion heater has been interrupted, this would stop the immersion heater from working. Check the circuit breaker to see if any switches have tripped, if so, push it back up and hopefully it will work. If it keeps tripping the electrics, call an electrician!

Faulty thermostat
The fix could be as easy as pressing the reset button on the thermostat. Or you may need to replace the thermostat for the immersion heater to work.

Damaged heating element
Due to age, the element may have corroded and simply need replacing.

Limescale
Limescale can cause numerous issues with a system, including damaging the heating element.

Lack of insulation
If the cylinder ‘jacket’ is no longer seated correctly around the cylinder, this could cause the cylinder to lose heat or result in the water taking longer to heat up. A quick fix of replacing the insulation might solve the issue.

Do I need a plumber or gas engineer to fix the hot water immersion heater?

A plumber or gas heating engineer can replace your immersion heater. It does make more sense to call out a gas engineer so that if the fault extends beyond the immersion heater, the engineer can repair the boiler as well while still on site.

How much will it cost to replace a hot water immersion heater?

When replacing your immersion heater, try replacing it with the same size. There should be a label at the top of the immersion heater with the specifications written on it. If you cannot see this, the heating engineer replacing the immersion heater should be able to advise you on which size heater to fit. The cost of  replacing a hot water immersion heater will be dependant on a few factors;

Type of immersion heater
Copper is a more budget friendly immersion heater to fit than a titanium immersion heater material wise. Although the labour time needed to fit is the same time regardless of the material chosen.

Length of time fitting
This depends on accessibility of the hot water cylinder and the immersion heater. Hopefully the hot water cylinder is housed in an airing cupboard with space around it to access. The tank needs to be drained so the size of the tank will determine the labour time draining and refilling the tank.

Number of Heating Elements
Immersion heaters can have numerous heating elements and of course a single heating element will be cheaper but a dual heating element will save you money in the long run being more energy efficient. If you are replacing just one element on a multi element cylinder, the top element will be far quicker to replace as the water will only have to be drained just past the element. However, it may be worth getting all of the heating elements changed in one go to avoid having to go through this process again. If an element has corroded, chances are the other elements are in a similar condition and it is just a matter of time.

Descale
Removing the lime scale that is built up in the hot water cylinder will prolong the life of any immersion heater. So when changing the immersion heater, before replacing the new parts, consider also descaling the cylinder.

When gathering quotes from various heating engineers to fit the new immersion heater, budget for an engineer to be with you for anywhere from 2 hours to 4 hours of labour time. 

Cost to replace an immersion heater

Per

Average total labour cost

Replace a single immersion heater

Per hour

£270

Replace a dual immersion heater

Per hour

£290

Descale a hot water cylinder

Per hour

£300

Replace a top immersion heater on a dual heater

Per hour

£240

Replacing a thermostat on an immersion heater

Per hour

£90

How long do hot water immersion heaters last?

The lifespan of an immersion heater will depend on the type of hard water area you live in and how often in a day your immersion heater comes on, heating the water. If you are in a very hard water area, prone to a lot of limescale and do not have a water softener on your system, and like to have the water set to heat numerous times of day, the immersion heater may need to be replaced every 5 years. This life can be prolonged with a descale to keep the limescale from building up around the heating element.

Is the heating element a universal fit for all hot water cylinders?

There are different types of immersion heaters that can be fitted to a hot water cylinder. Always be sure to take the advice of the gas engineer who will supply and fit the immersion heater and in most cases they will source like for like when replacing your immersion heater.

Some immersion heater types available for UK hot water cylinders include;

In-line Heaters
Also known as circulation heaters, and comes in a choice of material (e.g.; stainless steel, titanium, and standard steel). These In-line heaters are easy to install and efficient.

Flange Heaters
Flange immersion heaters are compatible with oil, fuel, water, gas, and thermal fluids, coming in shapes including straight or L-shaped. They offer the best resistance against corrosion.

Screw Plug Heaters
Screw plug immersion heaters are low-maintenance options that can heat different fluids, liquids and gases with direct contact.

Over the Side Heaters
These immersion heaters are easy to maintain and take up only a small amount of space as they are installed on the top of a tank. The element directly engages either on the side or bottom of the tank.


Estimates for common heating engineer jobs;

Job Estimate
Cost to replace a hot water immersion heater £275
Cost to fit underfloor heating £250
Cost to replace a vented hot water cylinder £330
Cost to replace a heating programmer £180
Cost to powerflush a central heating system £500 Visit
New combi or system boiler installation – like for like replacement £500
Cost to install a ground source heat pump £3750
Cost to fix a boiler fault error code £85
Cost to replace an unvented hot water cylinder, e.g., Megaflo £305
Cost to fit thermostatic radiator valves (TRVs) £94
Cost to fit smart heating controls £100
Cost to fit a radiator £80
Boiler service cost £90
Boiler repair costs (e.g. pump, diverter valve or heat exchanger) £333
Cost to install an air source heat pump £556
Replacement of a vented system £580

Rates for other trades

Replace a hot water immersion heater cost in the UK
Replace a hot water immersion heater cost in the UK (excluding VAT or callout charges)
Location in UKReplace a hot water immersion heater cost
Replace a hot water immersion heater near Aberdeen£289
Replace a hot water immersion heater near Amber Valley£246
Replace a hot water immersion heater near Angus£275
Replace a hot water immersion heater near Arun£278
Replace a hot water immersion heater near Ashfield£244
Replace a hot water immersion heater near Aylesbury Vale£286
Replace a hot water immersion heater near Barnsley£239
Replace a hot water immersion heater near Basildon£269
Replace a hot water immersion heater near Basingstoke & Deane£278
Replace a hot water immersion heater near Bassetlaw£250
Replace a hot water immersion heater near Bath & North East Somerset£265
Replace a hot water immersion heater near Bedford£288
Replace a hot water immersion heater near Belfast£217
Replace a hot water immersion heater near Birmingham£238
Replace a hot water immersion heater near Blackburn£242
Replace a hot water immersion heater near Blackpool£255
Replace a hot water immersion heater near Bolton£254
Replace a hot water immersion heater near Bournemouth£276
Replace a hot water immersion heater near Bracknell Forest£292
Replace a hot water immersion heater near Bradford£240
Replace a hot water immersion heater near Braintree£263
Replace a hot water immersion heater near Breckland£247
Replace a hot water immersion heater near Bridgend£231
Replace a hot water immersion heater near Brighton£268
Replace a hot water immersion heater near Bristol£258
Replace a hot water immersion heater near Broadland£272
Replace a hot water immersion heater near Broxtowe£242
Replace a hot water immersion heater near Bury£252
Replace a hot water immersion heater near Caerphilly£231
Replace a hot water immersion heater near Calderdale£235
Replace a hot water immersion heater near Cambridge£280
Replace a hot water immersion heater near Canterbury£250
Replace a hot water immersion heater near Cardiff£237
Replace a hot water immersion heater near Carmarthenshire£204
Replace a hot water immersion heater near Charnwood£235
Replace a hot water immersion heater near Chelmsford£264
Replace a hot water immersion heater near Cheltenham£315
Replace a hot water immersion heater near Cherwell£282
Replace a hot water immersion heater near Chester£224
Replace a hot water immersion heater near Colchester£260
Replace a hot water immersion heater near Conway£209
Replace a hot water immersion heater near Coventry£239
Replace a hot water immersion heater near Crewe & Nantwich£242
Replace a hot water immersion heater near Dacorum£285
Replace a hot water immersion heater near Derby£235
Replace a hot water immersion heater near Doncaster£248
Replace a hot water immersion heater near Dover£239
Replace a hot water immersion heater near Dudley£239
Replace a hot water immersion heater near Dumfries & Galloway£257
Replace a hot water immersion heater near Dundee£279
Replace a hot water immersion heater near East Ayrshire£195
Replace a hot water immersion heater near East Devon£252
Replace a hot water immersion heater near East Dunbartonshire£290
Replace a hot water immersion heater near East Hampshire£274
Replace a hot water immersion heater near East Hertfordshire£282
Replace a hot water immersion heater near East Lindsey£224
Replace a hot water immersion heater near East Riding£201
Replace a hot water immersion heater near Eastleigh£285
Replace a hot water immersion heater near Edinburgh£267
Replace a hot water immersion heater near Elmbridge£297
Replace a hot water immersion heater near Epping Forest£297
Replace a hot water immersion heater near Erewash£238
Replace a hot water immersion heater near Exeter£262
Replace a hot water immersion heater near Falkirk£280
Replace a hot water immersion heater near Fife£266
Replace a hot water immersion heater near Flintshire£231
Replace a hot water immersion heater near Gateshead£265
Replace a hot water immersion heater near Gedling£240
Replace a hot water immersion heater near Glasgow£284
Replace a hot water immersion heater near Gloucester£327
Replace a hot water immersion heater near Guildford£301
Replace a hot water immersion heater near Gwynedd£237
Replace a hot water immersion heater near Halton£241
Replace a hot water immersion heater near Harrogate£233
Replace a hot water immersion heater near Havant & Waterloo£271
Replace a hot water immersion heater near Highland£325
Replace a hot water immersion heater near Horsham£273
Replace a hot water immersion heater near Huntingdonshire£276
Replace a hot water immersion heater near Ipswich£308
Replace a hot water immersion heater near Isle of Wight£267
Replace a hot water immersion heater near Kings Lynn & West Norfolk£265
Replace a hot water immersion heater near Kingston-upon-Hull£201
Replace a hot water immersion heater near Kirklees£233
Replace a hot water immersion heater near Knowsley£237
Replace a hot water immersion heater near Lancaster£275
Replace a hot water immersion heater near Leeds£235
Replace a hot water immersion heater near Leicester£237
Replace a hot water immersion heater near Lisburn£217
Replace a hot water immersion heater near Liverpool£237
Replace a hot water immersion heater near London£294
Replace a hot water immersion heater near Luton£292
Replace a hot water immersion heater near Macclesfield£250
Replace a hot water immersion heater near Maidstone£260
Replace a hot water immersion heater near Manchester£246
Replace a hot water immersion heater near Mid Bedfordshire£283
Replace a hot water immersion heater near Mid Sussex£279
Replace a hot water immersion heater near Middlesbrough£250
Replace a hot water immersion heater near Milton Keynes£287
Replace a hot water immersion heater near Neath Port Talbot£239
Replace a hot water immersion heater near New Forest£274
Replace a hot water immersion heater near Newbury£279
Replace a hot water immersion heater near Newcastle-under-Lyme£231
Replace a hot water immersion heater near Newcastle-upon-Tyne£267
Replace a hot water immersion heater near Newport£239
Replace a hot water immersion heater near North Ayrshire£229
Replace a hot water immersion heater near North East Lincolnshire£259
Replace a hot water immersion heater near North Hertfordshire£285
Replace a hot water immersion heater near North Lanarkshire£286
Replace a hot water immersion heater near North Lincolnshire£226
Replace a hot water immersion heater near North Somerset£253
Replace a hot water immersion heater near North Tyneside£264
Replace a hot water immersion heater near North Wiltshire£315
Replace a hot water immersion heater near Northampton£280
Replace a hot water immersion heater near Norwich£265
Replace a hot water immersion heater near Nottingham£235
Replace a hot water immersion heater near Nuneaton & Bedworth£237
Replace a hot water immersion heater near Oldham£249
Replace a hot water immersion heater near Oxford£286
Replace a hot water immersion heater near Pembrokeshire£209
Replace a hot water immersion heater near Perth & Kinross£275
Replace a hot water immersion heater near Peterborough£279
Replace a hot water immersion heater near Plymouth£251
Replace a hot water immersion heater near Poole£275
Replace a hot water immersion heater near Portsmouth£268
Replace a hot water immersion heater near Powys£313
Replace a hot water immersion heater near Preston£254
Replace a hot water immersion heater near Reading£293
Replace a hot water immersion heater near Redcar & Cleveland£241
Replace a hot water immersion heater near Reigate & Banstead£296
Replace a hot water immersion heater near Renfrewshire£273
Replace a hot water immersion heater near Rhondda, Cynon, Taff£221
Replace a hot water immersion heater near Rochdale£249
Replace a hot water immersion heater near Rochester-upon-Medway£285
Replace a hot water immersion heater near Rotherham£242
Replace a hot water immersion heater near Salford£245
Replace a hot water immersion heater near Salisbury£256
Replace a hot water immersion heater near Sandwell£237
Replace a hot water immersion heater near Scarborough£247
Replace a hot water immersion heater near Scottish Borders£375
Replace a hot water immersion heater near Sefton£237
Replace a hot water immersion heater near Sevenoaks£272
Replace a hot water immersion heater near Sheffield£247
Replace a hot water immersion heater near Slough£295
Replace a hot water immersion heater near Solihull£238
Replace a hot water immersion heater near South Ayrshire£232
Replace a hot water immersion heater near South Bedfordshire£288
Replace a hot water immersion heater near South Cambridgeshire£270
Replace a hot water immersion heater near South Gloucestershire£261
Replace a hot water immersion heater near South Kesteven£277
Replace a hot water immersion heater near South Lanarkshire£281
Replace a hot water immersion heater near South Oxfordshire£279
Replace a hot water immersion heater near South Somerset£268
Replace a hot water immersion heater near South Tyneside£264
Replace a hot water immersion heater near Southampton£282
Replace a hot water immersion heater near Southend-on-Sea£260
Replace a hot water immersion heater near St Albans£294
Replace a hot water immersion heater near St Helens£236
Replace a hot water immersion heater near Stafford£243
Replace a hot water immersion heater near Stockport£248
Replace a hot water immersion heater near Stockton-on-Tees£252
Replace a hot water immersion heater near Stoke-on-Trent£231
Replace a hot water immersion heater near Stratford-on-Avon£251
Replace a hot water immersion heater near Stroud£293
Replace a hot water immersion heater near Suffolk Coastal£325
Replace a hot water immersion heater near Sunderland£264
Replace a hot water immersion heater near Swale£257
Replace a hot water immersion heater near Swansea£233
Replace a hot water immersion heater near Tameside£246
Replace a hot water immersion heater near Teignbridge£257
Replace a hot water immersion heater near Tendring£292
Replace a hot water immersion heater near Test Valley£266
Replace a hot water immersion heater near Thamesdown£315
Replace a hot water immersion heater near Thanet£260
Replace a hot water immersion heater near The Wrekin£259
Replace a hot water immersion heater near Thurrock£270
Replace a hot water immersion heater near Torbay£255
Replace a hot water immersion heater near Trafford£249
Replace a hot water immersion heater near Vale of Glamorgan£235
Replace a hot water immersion heater near Vale of White Horse£290
Replace a hot water immersion heater near Vale Royal£229
Replace a hot water immersion heater near Wakefield£240
Replace a hot water immersion heater near Walsall£237
Replace a hot water immersion heater near Warrington£250
Replace a hot water immersion heater near Warwick£246
Replace a hot water immersion heater near Waveney£258
Replace a hot water immersion heater near Waverley£290
Replace a hot water immersion heater near Wealden£275
Replace a hot water immersion heater near West Lancashire£240
Replace a hot water immersion heater near West Lothian£281
Replace a hot water immersion heater near West Wiltshire£315
Replace a hot water immersion heater near Wigan£242
Replace a hot water immersion heater near Windsor & Maidenhead£294
Replace a hot water immersion heater near Wirral£234
Replace a hot water immersion heater near Wokingham£294
Replace a hot water immersion heater near Wolverhampton£238
Replace a hot water immersion heater near Wrexham Maelor£296
Replace a hot water immersion heater near Wychavon£270
Replace a hot water immersion heater near Wycombe£300
Replace a hot water immersion heater near York£233