If you have a combi, there is no cylinder at the moment, so the first question is where one can go. If you have a system or regular boiler, you already have a cylinder, but it is unlikely to suit a heat pump, which needs a larger internal coil to heat water at lower temperatures. Regular boilers also have tanks in the loft that can usually be taken out, freeing space.
Households across Buckinghamshire moving off gas can have a survey in Buckinghamshire that compares running costs on realistic assumptions. Semi-detached and terraced houses in Buckinghamshire often have an airing cupboard that can be reused for a heat pump cylinder. Installers in Buckinghamshire take out the old boiler and flue and seal the wall opening as part of the job.
Who it suits
- Homes in England and Wales eligible for the Boiler Upgrade Scheme
- Boilers that are old, unreliable or due for replacement
- Households ready to give up gas entirely and drop the standing charge
- Combi owners who can find space for a hot water cylinder
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.
Gas boiler to heat pump prices in Buckinghamshire
Here are typical prices for replacing a gas boiler with a heat pump in Buckinghamshire, installed and including VAT. Use the guide price tool for a figure based on your home, then a survey confirms it in writing.
| Home | Typical size | Installed guide price | After £7,500 grant |
|---|---|---|---|
| 1–2 bedroom flat or small terrace | 4–5 kW | £10,000–£13,150 | £2,500–£5,650 |
| 2–3 bedroom terrace or semi | 5–7 kW | £11,050–£14,200 | £3,550–£6,700 |
| 3 bedroom semi or small detached | 6–9 kW | £12,600–£16,300 | £5,100–£8,800 |
| 4 bedroom detached | 8–12 kW | £14,700–£18,900 | £7,200–£11,400 |
| 5+ bedroom or larger older house | 11–16 kW | £17,350–£23,650 | £9,850–£16,150 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning.
Towns we cover in Buckinghamshire
We cover 13 towns in Buckinghamshire for replacing a gas boiler with a heat pump. 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 |
Replacing a gas boiler with a heat pump questions
Is there a grant to replace a gas boiler with a heat pump?
In England and Wales, the Boiler Upgrade Scheme gives £7,500 towards an air-to-water heat pump that replaces a gas boiler, for eligible owners of existing homes. The MCS-certified installer applies to Ofgem and deducts the grant from your quote, and Ofgem contacts you to confirm. Scotland has separate Home Energy Scotland funding, and Northern Ireland has no dedicated homeowner grant at present.
Will my hot water run out with a heat pump?
Not if the cylinder is sized properly for your household. The survey asks how many people live in the home, how many bathrooms you have and whether you prefer baths or showers, then sizes the cylinder to suit. The heat pump reheats the cylinder on a schedule, often overnight and again during the day, and an immersion heater acts as a backup.
What if my gas boiler is fairly new?
A newer boiler can still be replaced, but the timing is worth weighing. Some owners switch when the boiler needs a major repair; others prefer to plan the change for a convenient time. Across the UK, heat pump installation is zero-rated for VAT until 31 March 2027. A hybrid system, which keeps the boiler alongside a heat pump, is another option, though it is not eligible for the Boiler Upgrade Scheme in England and Wales.
Do I need to replace the cylinder I already have?
Usually, yes. Older cylinders have a small internal coil designed for water from a boiler at around 60–70°C, and they cannot take in heat quickly enough at the lower temperatures a heat pump runs at. A heat pump cylinder has a larger coil. On its own, a cylinder supplied and fitted has a guide price of £1,200–£2,200, installed and including VAT, though it is normally part of the full system price.