A heat pump hot water cylinder is an insulated tank that stores hot water heated by the heat pump, with a much larger internal coil than a cylinder designed for a boiler. Heat pumps heat water to a lower temperature than boilers, typically around 45–55°C, so a bigger coil is needed to pass heat into the stored water quickly. A standard boiler cylinder would heat slowly and make the heat pump work harder than it should.
Discharge pipe routes are planned at the survey so a Buckinghamshire cylinder can drain safely to the outside. Cylinder sizes for Buckinghamshire homes are based on the people living there and the bathrooms in daily use. Older houses in Buckinghamshire with loft tanks can usually have them removed when an unvented cylinder is fitted.
Who it suits
- Homes with solar PV that want to store daytime electricity as hot water
- Homes replacing a combi boiler that need space found for a cylinder
- Larger families or homes with two or more bathrooms
- Households with older vented cylinders and loft tanks who want mains-pressure showers
Grants and rules for heat pumps in England
Homes in Buckinghamshire can use the Boiler Upgrade Scheme, which takes £7,500 off the cost of an air source heat pump when it replaces fossil-fuel or electric heating. Replacing oil or LPG heating qualifies for £9,000 for installations from 21 July 2026 to 31 March 2027, and air-to-air systems for £2,500. The MCS-certified installer named in your quote applies for the grant and deducts it from the price.
Installing heat pumps is zero-rated for VAT across the UK until 31 March 2027. Since 29 May 2025, permitted development in England allows up to two air source heat pumps on a house, each up to 1.5 m³, with no blanket 1 m boundary rule — the installation must still meet the MCS planning standards, including the noise check. Listed buildings, flats and some conservation-area positions need extra consent, which we check at survey.
Heat pump hot water cylinders prices in Buckinghamshire
These are guide prices for Buckinghamshire, installed and including VAT. Your final price is fixed in a written quote after the survey and depends on the heat loss of the house, the radiators that need changing and where the unit goes.
| Work | Guide price |
|---|---|
| Heat pump hot water cylinder (supplied and fitted) | £1,250–£2,300 |
Supplied and fitted, inc VAT. Included in every full system price.
Towns we cover in Buckinghamshire
We cover 13 towns in Buckinghamshire for heat pump hot water cylinders. Each links to local guide prices and the grant position for England.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Milton Keynes | MK9 | Bletchley | 7 h 44 min |
| High Wycombe | HP11 | Marlow | 7 h 48 min |
| Aylesbury | HP20 | Princes Risborough | 7 h 46 min |
| Bletchley | MK2 | Milton Keynes | 7 h 44 min |
| Amersham | HP7 | Chesham | 7 h 48 min |
| Chesham | HP5 | Amersham | 7 h 48 min |
| Gerrards Cross | SL9 | Chalfont St Peter | 7 h 49 min |
| Chalfont St Peter | SL9 | Gerrards Cross | 7 h 48 min |
| Marlow | SL7 | High Wycombe | 7 h 49 min |
| Beaconsfield | HP9 | Chalfont St Peter | 7 h 48 min |
| Buckingham | MK18 | Brackley | 7 h 44 min |
| Olney | MK46 | Milton Keynes | 7 h 43 min |
| Princes Risborough | HP27 | Aylesbury | 7 h 47 min |
Heat pump hot water cylinders questions
Do I need good water pressure for an unvented cylinder?
Yes. An unvented cylinder runs at mains pressure, so it needs enough incoming pressure and flow to supply your taps and showers well. We measure your mains supply at the survey. If flow is low, options include a different cylinder type or an upgrade to the incoming supply pipe, which we explain before you commit.
Does a heat pump cylinder need servicing?
Yes. An unvented cylinder's safety devices should be checked every year, including the relief valves, the expansion vessel charge and the discharge pipework. This is normally done as part of the annual heat pump service, and it is often a condition of the cylinder manufacturer's warranty. Keep the cylinder paperwork with your heat pump handover documents.
I have a combi boiler. Where will the cylinder go?
Moving from a combi to a heat pump means finding space for a cylinder, usually somewhere around 600 mm square and up to about 2 m tall. Common choices are a bedroom or landing cupboard, a utility room, under the stairs or an integral garage. The surveyor looks at your layout and suggests options, including slimline models where space is tight.
How much does a heat pump cylinder cost?
A heat pump hot water cylinder has a guide price of £1,200–£2,200, installed and including VAT. In a full heat pump installation the cylinder is already included in the system guide price, so this figure mainly applies where a cylinder is replaced on its own. Capacity, coil design and the pipework needed affect where your price sits.