The hydrobox is a wall-mounted cabinet roughly the size of a boiler, or it can be built into a combined cylinder unit. It holds the heat exchanger, circulating pump, valves and controls. Outdoor units for split systems can be more compact than monobloc units of similar output, which helps where outdoor space is limited.
In Suffolk, a hydrobox often goes in an utility room or garage, with the cylinder alongside. Properties on exposed sites around Suffolk can avoid outdoor water pipes altogether with a split system. Flats and terraces in Suffolk with a small yard or flat roof can suit a compact split outdoor unit.
Who it suits
- Owners who would rather not use glycol or anti-freeze valves
- Houses with indoor wall space for a boiler-sized hydrobox
- Exposed or frost-prone sites where outdoor water pipes would be a risk
- Small yards, roofs or balconies that suit a more compact outdoor unit
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.
There is no VAT on installing a heat pump anywhere in the UK until 31 March 2027. In England most houses can have an air source heat pump under permitted development, provided the unit meets the MCS noise and siting standards; the old 1 m boundary limit was removed on 29 May 2025. We flag listed buildings, flats and sensitive conservation-area positions at survey.
Split system heat pumps prices in Suffolk
These are guide prices for Suffolk, 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.
| Home | Typical size | Installed guide price | After £7,500 grant |
|---|---|---|---|
| 1–2 bedroom flat or small terrace | 4–5 kW | £9,500–£12,500 | £2,000–£5,000 |
| 2–3 bedroom terrace or semi | 5–7 kW | £10,500–£13,500 | £3,000–£6,000 |
| 3 bedroom semi or small detached | 6–9 kW | £12,000–£15,500 | £4,500–£8,000 |
| 4 bedroom detached | 8–12 kW | £14,000–£18,000 | £6,500–£10,500 |
| 5+ bedroom or larger older house | 11–16 kW | £16,500–£22,500 | £9,000–£15,000 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning.
Towns we cover in Suffolk
We cover 11 towns in Suffolk for split system heat pumps. Each links to local guide prices and the grant position for England.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Ipswich | IP1 | Woodbridge | 7 h 44 min |
| Lowestoft | NR32 | Beccles | 7 h 39 min |
| Bury St Edmunds | IP33 | Stowmarket | 7 h 42 min |
| Haverhill | CB9 | Newmarket | 7 h 44 min |
| Felixstowe | IP11 | Harwich | 7 h 45 min |
| Sudbury | CO10 | Halstead | 7 h 44 min |
| Stowmarket | IP14 | Ipswich | 7 h 42 min |
| Newmarket | CB8 | Haverhill | 7 h 42 min |
| Beccles | NR34 | Lowestoft | 7 h 40 min |
| Southwold | IP18 | Beccles | 7 h 41 min |
| Woodbridge | IP12 | Ipswich | 7 h 43 min |
Split system heat pumps questions
Can a split system replace my combi boiler?
Yes, but like any air-to-water heat pump it needs a hot water cylinder, because it does not heat water instantly. The hydrobox can sometimes go where the combi was, with the cylinder in a cupboard, utility room or garage. Integrated units combining both are useful where one larger space is available. The survey checks what fits before the design is finalised.
How big is a hydrobox?
A hydrobox is typically about the size of a wall-mounted boiler, though sizes vary by make and model. It needs wall space near the cylinder with room around it for servicing and pipe connections. Some manufacturers combine the hydrobox and cylinder in a single floor-standing unit similar in size to a tall fridge-freezer, which can suit a utility room or garage.
Is a split system more efficient than a monobloc?
Not inherently. Efficiency depends far more on design, meaning correct sizing, low flow temperatures and good controls, than on whether the unit is split or monobloc. A split system can avoid the heat loss and glycol of a long outdoor water run, which helps in certain layouts. The survey estimates seasonal efficiency for the specific units proposed, so you can compare like for like.
Do I need an F-gas engineer for a split heat pump?
Yes. Split systems usually use a fluorinated refrigerant such as R32, so installing, servicing or repairing the refrigerant circuit must by law be done by an F-gas certified engineer. That covers joining the refrigerant pipes, testing them for leaks and charging the system. Your quote sets out who carries out each part of the installation, including the refrigerant work.