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.
Owners across West Glamorgan can compare split and monobloc designs side by side at a survey in West Glamorgan. Properties on exposed sites around West Glamorgan can avoid outdoor water pipes altogether with a split system. Flats and terraces in West Glamorgan with a small yard or flat roof can suit a compact split outdoor unit.
Who it suits
- Homes where the outdoor unit must sit some distance from the plant space
- 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
- Owners who would rather not use glycol or anti-freeze valves
Grants and rules for heat pumps in Wales
In Wales 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; £2,500 for air-to-air). The MCS-certified installer named in your quote applies to Ofgem for you, and the grant comes off your quote.
There is no VAT on installing a heat pump anywhere in the UK, Wales included, until 31 March 2027. Planning rules for heat pumps in Wales are set by the Welsh Government and differ from England's, so the surveyor checks the unit position against them.
Split system heat pumps prices in West Glamorgan
These are guide prices for West Glamorgan, 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 West Glamorgan
We cover 8 towns in West Glamorgan for split system heat pumps. Each links to local guide prices and the grant position for Wales.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Swansea | SA1 | Mumbles | 7 h 48 min |
| Neath | SA10 | Briton Ferry | 7 h 48 min |
| Briton Ferry | SA12 | Neath | 7 h 48 min |
| Gorseinon | SA4 | Swansea | 7 h 48 min |
| Clydach | SA6 | Pontardawe | 7 h 48 min |
| Mumbles | SA3 | Swansea | 7 h 49 min |
| Pontardawe | SA8 | Clydach | 7 h 47 min |
| Port Talbot | SA12 | Briton Ferry | 7 h 49 min |
Split system heat pumps questions
Is a split system eligible for the Boiler Upgrade Scheme?
Yes. A split air-to-water heat pump counts as an air source heat pump under the scheme, so in England and Wales eligible owners of existing homes can receive £7,500, or £9,000 when replacing oil or LPG within the published dates. The MCS-certified installer applies for you. Scotland's Home Energy Scotland funding is separate, and Northern Ireland has no dedicated homeowner grant at present.
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.
How far apart can the outdoor unit and hydrobox be?
It depends on the model: each manufacturer sets a maximum refrigerant pipe length and height difference, and longer runs may need extra refrigerant. In practice a split system allows more flexibility than a monobloc's water pipes, so the outdoor unit can often sit on the far side of a house, on a flat roof or round a corner. The survey measures the actual route.
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.