A split system heat pump is an air-to-water heat pump in two parts: an outdoor unit that collects heat from the air, and an indoor unit called a hydrobox where that heat is passed into the water for your heating and hot water. The two are connected by insulated refrigerant pipes rather than water pipes, so there is no water outside to freeze.
Installers covering Dumfries and Galloway keep refrigerant routes neat and protected along the outside wall. Properties on exposed sites around Dumfries and Galloway can avoid outdoor water pipes altogether with a split system. In Dumfries and Galloway homes where the clearest unit position is away from the plant cupboard, a split system allows a longer route indoors.
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
- Small yards, roofs or balconies that suit a more compact outdoor unit
- Exposed or frost-prone sites where outdoor water pipes would be a risk
Grants and rules for heat pumps in Scotland
The Boiler Upgrade Scheme does not apply in Scotland. Instead, homeowners in Dumfries and Galloway can apply to Home Energy Scotland for a grant of up to £7,500 towards a heat pump, with up to £1,500 more for eligible rural and island homes, plus an optional interest-free loan of up to £7,500. You need a written funding offer before any work starts.
Installing heat pumps is zero-rated for VAT across the UK until 31 March 2027. Scotland has its own permitted development rules for air source heat pumps and its own building standards, so we confirm what applies to your property at survey.
Split system heat pumps prices in Dumfries and Galloway
The ranges below are typical installed prices for homes in Dumfries and Galloway, including VAT. A survey sets the exact figure, because two similar-looking houses in Dumfries and Galloway can need quite different radiators and pipework.
| Home | Typical size | Installed guide price |
|---|---|---|
| 1–2 bedroom flat or small terrace | 4–5 kW | £9,700–£12,750 |
| 2–3 bedroom terrace or semi | 5–7 kW | £10,700–£13,750 |
| 3 bedroom semi or small detached | 6–9 kW | £12,250–£15,800 |
| 4 bedroom detached | 8–12 kW | £14,300–£18,350 |
| 5+ bedroom or larger older house | 11–16 kW | £16,850–£22,950 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning. In Scotland, Home Energy Scotland grants of up to £7,500 and interest-free loans may reduce the cost.
Towns we cover in Dumfries and Galloway
We cover 8 towns in Dumfries and Galloway for split system heat pumps. Each links to local guide prices and the grant position for Scotland.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Dumfries | DG1 | Lockerbie | 7 h 09 min |
| Annan | DG12 | Lockerbie | 7 h 10 min |
| Castle Douglas | DG7 | Dalbeattie | 7 h 11 min |
| Dalbeattie | DG5 | Castle Douglas | 7 h 11 min |
| Kirkcudbright | DG6 | Castle Douglas | 7 h 12 min |
| Lockerbie | DG11 | Annan | 7 h 08 min |
| Newton Stewart | DG8 | Kirkcudbright | 7 h 10 min |
| Stranraer | DG9 | Newton Stewart | 7 h 11 min |
Split system heat pumps questions
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.
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.
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.
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.