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 Dyfed, a hydrobox often goes in an utility room or garage, with the cylinder alongside. Flats and terraces in Dyfed with a small yard or flat roof can suit a compact split outdoor unit. Properties on exposed sites around Dyfed can avoid outdoor water pipes altogether with a split system.
Who it suits
- Owners who would rather not use glycol or anti-freeze valves
- 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
- Houses with indoor wall space for a boiler-sized hydrobox
Grants and rules for heat pumps in Wales
Homes in Dyfed can use the Boiler Upgrade Scheme, which applies in Wales as well as England: £7,500 towards an air source heat pump, or £9,000 when it replaces oil or LPG heating for installations from 21 July 2026 to 31 March 2027. The MCS-certified installer named in your quote applies and deducts the grant.
Installing heat pumps is zero-rated for VAT across the UK until 31 March 2027. Wales has its own permitted development rules for air source heat pumps, so we check what applies to your property, including listed building and conservation-area constraints, at the survey.
Split system heat pumps prices in Dyfed
The ranges below are typical installed prices for homes in Dyfed, including VAT. A survey sets the exact figure, because two similar-looking houses in Dyfed can need quite different radiators and pipework.
| 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 Dyfed
We cover 11 towns in Dyfed for split system heat pumps. Each links to local guide prices and the grant position for Wales.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Llanelli | SA15 | Gorseinon | 7 h 48 min |
| Ammanford | SA18 | Pontardawe | 7 h 47 min |
| Aberystwyth | SY23 | Machynlleth | 7 h 40 min |
| Carmarthen | SA31 | Llanelli | 7 h 46 min |
| Cardigan | SA43 | Fishguard | 7 h 44 min |
| Fishguard | SA65 | Haverfordwest | 7 h 44 min |
| Haverfordwest | SA61 | Milford Haven | 7 h 46 min |
| Lampeter | SA48 | Carmarthen | 7 h 43 min |
| Milford Haven | SA73 | Pembroke Dock | 7 h 47 min |
| Pembroke Dock | SA72 | Milford Haven | 7 h 48 min |
| Tenby | SA70 | Pembroke Dock | 7 h 48 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.
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.
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.