Because the refrigerant pipes are joined and charged on site, and split systems usually use a fluorinated refrigerant such as R32, the refrigerant work must by law be done by an F-gas certified engineer. That makes installation a little more involved than a monobloc, and any later repair to the refrigerant circuit also needs F-gas certified work. In return, a split system copes better with long or awkward routes between the outdoor unit and the house, within the limits the manufacturer sets.
Properties on exposed sites around County Londonderry can avoid outdoor water pipes altogether with a split system. In County Londonderry, a hydrobox often goes in an utility room or garage, with the cylinder alongside. Installers covering County Londonderry keep refrigerant routes neat and protected along the outside wall.
Who it suits
- Exposed or frost-prone sites where outdoor water pipes would be a risk
- Houses with indoor wall space for a boiler-sized hydrobox
- 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 Northern Ireland
Northern Ireland does not have a dedicated heat pump grant for homeowners at present, and the Boiler Upgrade Scheme does not apply here. Heat pumps have sometimes been funded through the Northern Ireland Sustainable Energy Programme, so it is worth checking what is open when you enquire about a home in County Londonderry.
Installing heat pumps has been zero-rated for VAT in Northern Ireland since 1 May 2023, in line with the rest of the UK, until 31 March 2027. Northern Ireland has its own permitted development rules and building regulations, and we confirm what applies to your property at survey.
Split system heat pumps prices in County Londonderry
The ranges below are typical installed prices for homes in County Londonderry, including VAT. A survey sets the exact figure, because two similar-looking houses in County Londonderry can need quite different radiators and pipework.
| Home | Typical size | Installed guide price |
|---|---|---|
| 1–2 bedroom flat or small terrace | 4–5 kW | £9,200–£12,150 |
| 2–3 bedroom terrace or semi | 5–7 kW | £10,200–£13,100 |
| 3 bedroom semi or small detached | 6–9 kW | £11,650–£15,050 |
| 4 bedroom detached | 8–12 kW | £13,600–£17,450 |
| 5+ bedroom or larger older house | 11–16 kW | £16,000–£21,850 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning. No dedicated heat pump grant currently applies in Northern Ireland.
Towns we cover in County Londonderry
We cover 7 towns in County Londonderry for split system heat pumps. Each links to local guide prices and the grant position for Northern Ireland.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Derry/Londonderry | BT48 | Limavady | 7 h 10 min |
| Coleraine | BT52 | Portstewart | 7 h 08 min |
| Dungiven | BT47 | Limavady | 7 h 11 min |
| Limavady | BT49 | Dungiven | 7 h 09 min |
| Maghera | BT46 | Magherafelt | 7 h 12 min |
| Magherafelt | BT45 | Maghera | 7 h 13 min |
| Portstewart | BT55 | Coleraine | 7 h 08 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 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.