Most heat pump cylinders are unvented, meaning they run at mains water pressure and give strong flow from every tap without a cold water tank in the loft. Unvented cylinders have safety controls that must be fitted and checked by someone qualified to work on them. We size the cylinder from your household and bathrooms, confirm your mains water supply can support it, and plan the space, pipework and discharge route at the survey.
Older houses in Hertfordshire with loft tanks can usually have them removed when an unvented cylinder is fitted. We check mains water pressure and flow at each Hertfordshire property before choosing a cylinder. Cylinder sizes for Hertfordshire homes are based on the people living there and the bathrooms in daily use.
Who it suits
- Homes replacing a combi boiler that need space found for a cylinder
- Households with older vented cylinders and loft tanks who want mains-pressure showers
- Every air-to-water heat pump installation, whatever the existing boiler
- Larger families or homes with two or more bathrooms
Grants and rules for heat pumps in England
In England the Boiler Upgrade Scheme gives £7,500 towards an air source heat pump (£9,000 if it replaces oil or LPG, from 21 July 2026 to 31 March 2027), and since 28 April 2026 a valid EPC is no longer needed. The grant is applied for by the MCS-certified installer and shown as a deduction on your quote.
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 Hertfordshire
Here are typical prices for heat pump hot water cylinders in Hertfordshire, installed and including VAT. Use the guide price tool for a figure based on your home, then a survey confirms it in writing.
| 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 Hertfordshire
We cover 17 towns in Hertfordshire 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 |
|---|---|---|---|
| Hemel Hempstead | HP2 | Berkhamsted | 7 h 47 min |
| Stevenage | SG1 | Hitchin | 7 h 45 min |
| St Albans | AL1 | Radlett | 7 h 47 min |
| Welwyn Garden City | AL8 | Hatfield | 7 h 46 min |
| Cheshunt | EN8 | Hoddesdon | 7 h 47 min |
| Hatfield | AL10 | Welwyn Garden City | 7 h 47 min |
| Bishop's Stortford | CM23 | Ware | 7 h 46 min |
| Hitchin | SG6 | Letchworth Garden City | 7 h 45 min |
| Hoddesdon | EN11 | Ware | 7 h 47 min |
| Letchworth Garden City | SG6 | Hitchin | 7 h 45 min |
| Harpenden | AL5 | St Albans | 7 h 46 min |
| Hertford | SG13 | Ware | 7 h 47 min |
| Berkhamsted | HP4 | Tring | 7 h 47 min |
| Ware | SG12 | Hertford | 7 h 46 min |
| Royston | SG7 | Letchworth Garden City | 7 h 44 min |
| Radlett | WD7 | St Albans | 7 h 48 min |
| Tring | HP23 | Berkhamsted | 7 h 47 min |
Heat pump hot water cylinders questions
Can I keep my existing hot water cylinder with a heat pump?
Usually not. Cylinders designed for boilers have a small coil that cannot transfer heat quickly at heat pump temperatures, so the water would reheat slowly and efficiency would suffer. A heat pump cylinder has a much larger coil. The new cylinder can often go in the same cupboard, though, if there is enough height and floor space.
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.
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.
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.