A vented hot water cylinder is also known as a gravity-fed hot water cylinder. This is because the vented cylinder works on a gravity system by having the water supplied from the cold water tank, also known as a header tank, which is often stored in the loft or on a higher floor, as the system relies on gravity to build pressure.

The name 'vented hot water cylinder' is because the 'open vent' is a pipe which acts as a safety mechanism releasing built-up pressure. The vent pipe runs from the cylinder back up to the feed and expansion tank, releasing the built-up water pressure in the tank to stop the system from overheating. Vented cylinders often are made of copper or stainless steel and a cheaper system to install than an unvented system.

When should I choose a vented cylinder?

If it is time for a heating engineer to replace your vented hot water cylinder, the easiest installation is usually going with a similar set-up to what is already installed needing replacing. This will be because the pipework is in place, ready for the cylinder to just be swapped out for a newer version.

Older UK properties tend to have vented cylinders. This means the pipework plumbed in throughout the home, was designed for a low-pressure system. Replacing the hot water cylinder with a different set-up may require pipework to be replaced to handle the higher pressure of a pressurised system. This of course would add to the installation costs.

Choosing a vented cylinder will need a home that has a loft space for the header tank or an upstairs storage space as the cold water tank does need to be positioned high enough to create the pressure from gravity for it to work best.

If the mains water pressure supply from your road into your home is low, your system will benefit from replacing the cylinder with a vented cylinder. This way gravity can help create a better water pressure. A vented hot water cylinder can either be heated directly by an immersion heater in the cylinder or indirectly by a boiler. A lot of UK homes rely on a gas boiler to indirectly heat the water but still have an immersion heater as a backup in case of a boiler breakdown.

Can I fit a pump on a vented cylinder?

If your vented hot water system is struggling to maintain pressure, it is possible to fit an electric pump to the vented cylinder. A heating engineer can fit a shower pump to the system to improve the water pressure from a gravity system.

When it comes to improving the pressure and fitting a pump, there are numerous options of pump styles to be fitted to the water supply;

  • Small twin-impeller pump for a single shower
  • Larger pump to supply better water pressure to all of the taps in a bathroom, not just the shower
  • Centrifugal pump to supply the entire home with a stronger water pressure

How much will it cost to install a vented hot water cylinder?

Replacing a vented hot water cylinder is not too expensive a job. Including the cylinder and labour, this could cost from £500 because if replacing” like-for-like”, the job may be able to be completed in less than 3 hours. The more complicated the job, the longer the heating engineer will need on site but still should only be a day's labour charge to fit a new vented hot water cylinder.

Cost to replace a vented hot water system

Per

Average total labour cost

Replacing a vented hot water cylinder

Per hour

£300

Installing a vented hot water cylinder and replacing pipework

Per hour

£350

Fitting a larger capacity vented hot water cylinder

Per hour

£400

Diagnosing a fault on a vented hot water cylinder

Per hour

£80

How do I know if my vented hot water cylinder needs replacing?

A vented hot water cylinder should last 10 - 15 years before needing replacing. Of course, the length of time depends on how well it has been maintained.

If you start noticing signs of leaks, the cylinder might be cracked or have a pin-hole and may need replacing.

Limescale can build up in the cylinder over the years and this can cause blockages as well as cause the cylinder to not heat effectively or make noises.

If the water from hot taps only is coming out with a smell or discoloured, this could mean that the heat exchanger inside the cylinder has burst and hot water and heating water are mixing. This is dangerous and would mean that the cylinder needs urgent replacing.

Another reason for discoloured or smelly water can be the result of the cylinder's anode rod corroding and that part might need replacing or the entire cylinder replacing.

Which is better, vented or unvented?

When it comes to wondering which out of vented and unvented cylinders is better, vented cylinders require almost no maintenance and are a simpler system to install, therefore often resulting in a cheaper choice. As already mentioned, older UK homes are already plumbed in for vented cylinders so all that is needed is a ‘like for like’ replacement rather than the expense of upgrading plumbing for an unvented system.

Other advantages of vented systems include;

- If the roads water supply is cut off, then the header tank should have a full supply of water, keeping you going until the roads water supply is fully restored

and

- Consistent water pressure and supply when mains pressure is low due to high demand

The only major downside is the space needed for the header tank in the loft.

Of course, unvented systems have their advantages too, mains pressure hot water will generally have a better flow rate (provided the mains supply is strong) and youn gain space without needing the tank in the loft.


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

Fit or replace a vented hot water cylinder cost in the UK
Fit or replace a vented hot water cylinder cost in the UK (excluding VAT or callout charges)
Location in UKFit or replace a vented hot water cylinder cost
Fit or replace a vented hot water cylinder near Aberdeen£314
Fit or replace a vented hot water cylinder near Amber Valley£271
Fit or replace a vented hot water cylinder near Angus£300
Fit or replace a vented hot water cylinder near Arun£303
Fit or replace a vented hot water cylinder near Ashfield£269
Fit or replace a vented hot water cylinder near Aylesbury Vale£311
Fit or replace a vented hot water cylinder near Barnsley£264
Fit or replace a vented hot water cylinder near Basildon£294
Fit or replace a vented hot water cylinder near Basingstoke & Deane£303
Fit or replace a vented hot water cylinder near Bassetlaw£275
Fit or replace a vented hot water cylinder near Bath & North East Somerset£290
Fit or replace a vented hot water cylinder near Bedford£313
Fit or replace a vented hot water cylinder near Belfast£242
Fit or replace a vented hot water cylinder near Birmingham£263
Fit or replace a vented hot water cylinder near Blackburn£267
Fit or replace a vented hot water cylinder near Blackpool£280
Fit or replace a vented hot water cylinder near Bolton£279
Fit or replace a vented hot water cylinder near Bournemouth£301
Fit or replace a vented hot water cylinder near Bracknell Forest£317
Fit or replace a vented hot water cylinder near Bradford£265
Fit or replace a vented hot water cylinder near Braintree£288
Fit or replace a vented hot water cylinder near Breckland£272
Fit or replace a vented hot water cylinder near Bridgend£256
Fit or replace a vented hot water cylinder near Brighton£293
Fit or replace a vented hot water cylinder near Bristol£283
Fit or replace a vented hot water cylinder near Broadland£297
Fit or replace a vented hot water cylinder near Broxtowe£267
Fit or replace a vented hot water cylinder near Bury£277
Fit or replace a vented hot water cylinder near Caerphilly£256
Fit or replace a vented hot water cylinder near Calderdale£260
Fit or replace a vented hot water cylinder near Cambridge£305
Fit or replace a vented hot water cylinder near Canterbury£275
Fit or replace a vented hot water cylinder near Cardiff£262
Fit or replace a vented hot water cylinder near Carmarthenshire£229
Fit or replace a vented hot water cylinder near Charnwood£260
Fit or replace a vented hot water cylinder near Chelmsford£289
Fit or replace a vented hot water cylinder near Cheltenham£340
Fit or replace a vented hot water cylinder near Cherwell£307
Fit or replace a vented hot water cylinder near Chester£249
Fit or replace a vented hot water cylinder near Colchester£285
Fit or replace a vented hot water cylinder near Conway£234
Fit or replace a vented hot water cylinder near Coventry£264
Fit or replace a vented hot water cylinder near Crewe & Nantwich£267
Fit or replace a vented hot water cylinder near Dacorum£310
Fit or replace a vented hot water cylinder near Derby£260
Fit or replace a vented hot water cylinder near Doncaster£273
Fit or replace a vented hot water cylinder near Dover£264
Fit or replace a vented hot water cylinder near Dudley£264
Fit or replace a vented hot water cylinder near Dumfries & Galloway£282
Fit or replace a vented hot water cylinder near Dundee£304
Fit or replace a vented hot water cylinder near East Ayrshire£220
Fit or replace a vented hot water cylinder near East Devon£277
Fit or replace a vented hot water cylinder near East Dunbartonshire£315
Fit or replace a vented hot water cylinder near East Hampshire£299
Fit or replace a vented hot water cylinder near East Hertfordshire£307
Fit or replace a vented hot water cylinder near East Lindsey£249
Fit or replace a vented hot water cylinder near East Riding£226
Fit or replace a vented hot water cylinder near Eastleigh£310
Fit or replace a vented hot water cylinder near Edinburgh£292
Fit or replace a vented hot water cylinder near Elmbridge£322
Fit or replace a vented hot water cylinder near Epping Forest£322
Fit or replace a vented hot water cylinder near Erewash£263
Fit or replace a vented hot water cylinder near Exeter£287
Fit or replace a vented hot water cylinder near Falkirk£305
Fit or replace a vented hot water cylinder near Fife£291
Fit or replace a vented hot water cylinder near Flintshire£256
Fit or replace a vented hot water cylinder near Gateshead£290
Fit or replace a vented hot water cylinder near Gedling£265
Fit or replace a vented hot water cylinder near Glasgow£309
Fit or replace a vented hot water cylinder near Gloucester£352
Fit or replace a vented hot water cylinder near Guildford£326
Fit or replace a vented hot water cylinder near Gwynedd£262
Fit or replace a vented hot water cylinder near Halton£266
Fit or replace a vented hot water cylinder near Harrogate£258
Fit or replace a vented hot water cylinder near Havant & Waterloo£296
Fit or replace a vented hot water cylinder near Highland£350
Fit or replace a vented hot water cylinder near Horsham£298
Fit or replace a vented hot water cylinder near Huntingdonshire£301
Fit or replace a vented hot water cylinder near Ipswich£333
Fit or replace a vented hot water cylinder near Isle of Wight£292
Fit or replace a vented hot water cylinder near Kings Lynn & West Norfolk£290
Fit or replace a vented hot water cylinder near Kingston-upon-Hull£226
Fit or replace a vented hot water cylinder near Kirklees£258
Fit or replace a vented hot water cylinder near Knowsley£262
Fit or replace a vented hot water cylinder near Lancaster£300
Fit or replace a vented hot water cylinder near Leeds£260
Fit or replace a vented hot water cylinder near Leicester£262
Fit or replace a vented hot water cylinder near Lisburn£242
Fit or replace a vented hot water cylinder near Liverpool£262
Fit or replace a vented hot water cylinder near London£319
Fit or replace a vented hot water cylinder near Luton£317
Fit or replace a vented hot water cylinder near Macclesfield£275
Fit or replace a vented hot water cylinder near Maidstone£285
Fit or replace a vented hot water cylinder near Manchester£271
Fit or replace a vented hot water cylinder near Mid Bedfordshire£308
Fit or replace a vented hot water cylinder near Mid Sussex£304
Fit or replace a vented hot water cylinder near Middlesbrough£275
Fit or replace a vented hot water cylinder near Milton Keynes£312
Fit or replace a vented hot water cylinder near Neath Port Talbot£264
Fit or replace a vented hot water cylinder near New Forest£299
Fit or replace a vented hot water cylinder near Newbury£304
Fit or replace a vented hot water cylinder near Newcastle-under-Lyme£256
Fit or replace a vented hot water cylinder near Newcastle-upon-Tyne£292
Fit or replace a vented hot water cylinder near Newport£264
Fit or replace a vented hot water cylinder near North Ayrshire£254
Fit or replace a vented hot water cylinder near North East Lincolnshire£284
Fit or replace a vented hot water cylinder near North Hertfordshire£310
Fit or replace a vented hot water cylinder near North Lanarkshire£311
Fit or replace a vented hot water cylinder near North Lincolnshire£251
Fit or replace a vented hot water cylinder near North Somerset£278
Fit or replace a vented hot water cylinder near North Tyneside£289
Fit or replace a vented hot water cylinder near North Wiltshire£340
Fit or replace a vented hot water cylinder near Northampton£305
Fit or replace a vented hot water cylinder near Norwich£290
Fit or replace a vented hot water cylinder near Nottingham£260
Fit or replace a vented hot water cylinder near Nuneaton & Bedworth£262
Fit or replace a vented hot water cylinder near Oldham£274
Fit or replace a vented hot water cylinder near Oxford£311
Fit or replace a vented hot water cylinder near Pembrokeshire£234
Fit or replace a vented hot water cylinder near Perth & Kinross£300
Fit or replace a vented hot water cylinder near Peterborough£304
Fit or replace a vented hot water cylinder near Plymouth£276
Fit or replace a vented hot water cylinder near Poole£300
Fit or replace a vented hot water cylinder near Portsmouth£293
Fit or replace a vented hot water cylinder near Powys£338
Fit or replace a vented hot water cylinder near Preston£279
Fit or replace a vented hot water cylinder near Reading£318
Fit or replace a vented hot water cylinder near Redcar & Cleveland£266
Fit or replace a vented hot water cylinder near Reigate & Banstead£321
Fit or replace a vented hot water cylinder near Renfrewshire£298
Fit or replace a vented hot water cylinder near Rhondda, Cynon, Taff£246
Fit or replace a vented hot water cylinder near Rochdale£274
Fit or replace a vented hot water cylinder near Rochester-upon-Medway£310
Fit or replace a vented hot water cylinder near Rotherham£267
Fit or replace a vented hot water cylinder near Salford£270
Fit or replace a vented hot water cylinder near Salisbury£281
Fit or replace a vented hot water cylinder near Sandwell£262
Fit or replace a vented hot water cylinder near Scarborough£272
Fit or replace a vented hot water cylinder near Scottish Borders£400
Fit or replace a vented hot water cylinder near Sefton£262
Fit or replace a vented hot water cylinder near Sevenoaks£297
Fit or replace a vented hot water cylinder near Sheffield£272
Fit or replace a vented hot water cylinder near Slough£320
Fit or replace a vented hot water cylinder near Solihull£263
Fit or replace a vented hot water cylinder near South Ayrshire£257
Fit or replace a vented hot water cylinder near South Bedfordshire£313
Fit or replace a vented hot water cylinder near South Cambridgeshire£295
Fit or replace a vented hot water cylinder near South Gloucestershire£286
Fit or replace a vented hot water cylinder near South Kesteven£302
Fit or replace a vented hot water cylinder near South Lanarkshire£306
Fit or replace a vented hot water cylinder near South Oxfordshire£304
Fit or replace a vented hot water cylinder near South Somerset£293
Fit or replace a vented hot water cylinder near South Tyneside£289
Fit or replace a vented hot water cylinder near Southampton£307
Fit or replace a vented hot water cylinder near Southend-on-Sea£285
Fit or replace a vented hot water cylinder near St Albans£319
Fit or replace a vented hot water cylinder near St Helens£261
Fit or replace a vented hot water cylinder near Stafford£268
Fit or replace a vented hot water cylinder near Stockport£273
Fit or replace a vented hot water cylinder near Stockton-on-Tees£277
Fit or replace a vented hot water cylinder near Stoke-on-Trent£256
Fit or replace a vented hot water cylinder near Stratford-on-Avon£276
Fit or replace a vented hot water cylinder near Stroud£318
Fit or replace a vented hot water cylinder near Suffolk Coastal£350
Fit or replace a vented hot water cylinder near Sunderland£289
Fit or replace a vented hot water cylinder near Swale£282
Fit or replace a vented hot water cylinder near Swansea£258
Fit or replace a vented hot water cylinder near Tameside£271
Fit or replace a vented hot water cylinder near Teignbridge£282
Fit or replace a vented hot water cylinder near Tendring£317
Fit or replace a vented hot water cylinder near Test Valley£291
Fit or replace a vented hot water cylinder near Thamesdown£340
Fit or replace a vented hot water cylinder near Thanet£285
Fit or replace a vented hot water cylinder near The Wrekin£284
Fit or replace a vented hot water cylinder near Thurrock£295
Fit or replace a vented hot water cylinder near Torbay£280
Fit or replace a vented hot water cylinder near Trafford£274
Fit or replace a vented hot water cylinder near Vale of Glamorgan£260
Fit or replace a vented hot water cylinder near Vale of White Horse£315
Fit or replace a vented hot water cylinder near Vale Royal£254
Fit or replace a vented hot water cylinder near Wakefield£265
Fit or replace a vented hot water cylinder near Walsall£262
Fit or replace a vented hot water cylinder near Warrington£275
Fit or replace a vented hot water cylinder near Warwick£271
Fit or replace a vented hot water cylinder near Waveney£283
Fit or replace a vented hot water cylinder near Waverley£315
Fit or replace a vented hot water cylinder near Wealden£300
Fit or replace a vented hot water cylinder near West Lancashire£265
Fit or replace a vented hot water cylinder near West Lothian£306
Fit or replace a vented hot water cylinder near West Wiltshire£340
Fit or replace a vented hot water cylinder near Wigan£267
Fit or replace a vented hot water cylinder near Windsor & Maidenhead£319
Fit or replace a vented hot water cylinder near Wirral£259
Fit or replace a vented hot water cylinder near Wokingham£319
Fit or replace a vented hot water cylinder near Wolverhampton£263
Fit or replace a vented hot water cylinder near Wrexham Maelor£321
Fit or replace a vented hot water cylinder near Wychavon£295
Fit or replace a vented hot water cylinder near Wycombe£325
Fit or replace a vented hot water cylinder near York£258