A monobloc heat pump is an air-to-water unit with the entire refrigerant circuit, including the compressor, heat exchangers and refrigerant, sealed inside the outdoor casing. Heat is passed to water inside the unit, and insulated water pipes carry it into the house to the cylinder and heating system. Nothing containing refrigerant comes indoors, which is a big part of why monobloc units suit so many UK homes.
Bungalows in the Scottish Borders often let the unit sit right beside the plant cupboard, keeping water pipes short. In exposed spots around the Scottish Borders, frost protection for the outdoor pipework is chosen with the site in mind. Houses in the Scottish Borders with a rear wall close to the cylinder location usually suit a monobloc unit with a short pipe run.
Who it suits
- Houses and bungalows with outdoor space close to where pipes enter the home
- Homes where the unit can sit within a short pipe run of the cylinder
- Owners who want the simplest installation, with no indoor refrigerant
- Households that want to keep refrigerant work out of routine servicing
Grants and rules for heat pumps in Scotland
In Scotland, heat pump funding comes through Home Energy Scotland rather than the Boiler Upgrade Scheme: a grant of up to £7,500 (up to £1,500 extra for eligible rural and island homes) and an optional interest-free loan of up to £7,500. For a home in the Scottish Borders, apply and receive the written offer before the installation date is fixed.
There is no VAT on installing a heat pump anywhere in the UK, Scotland included, until 31 March 2027. Scottish permitted development rules and building standards apply, and the surveyor checks the unit position and any listed or conservation-area constraints.
Monobloc heat pumps prices in the Scottish Borders
The ranges below are typical installed prices for homes in the Scottish Borders, including VAT. A survey sets the exact figure, because two similar-looking houses in the Scottish Borders 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 the Scottish Borders
We cover 8 towns in the Scottish Borders for monobloc heat pumps. Each links to local guide prices and the grant position for Scotland.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Duns | TD11 | Eyemouth | 7 h 00 min |
| Eyemouth | TD14 | Duns | 6 h 58 min |
| Galashiels | TD1 | Selkirk | 7 h 02 min |
| Hawick | TD9 | Selkirk | 7 h 04 min |
| Jedburgh | TD8 | Kelso | 7 h 04 min |
| Kelso | TD5 | Jedburgh | 7 h 02 min |
| Peebles | EH45 | Penicuik | 7 h 01 min |
| Selkirk | TD7 | Galashiels | 7 h 03 min |
Monobloc heat pumps questions
Is glycol or anti-freeze valves the better option?
Neither is right for every home. Glycol gives reliable frost protection without draining but slightly reduces efficiency and needs its concentration checked at servicing. Anti-freeze valves keep the system water plain but release water if pipes near freezing during a power cut, so the system then needs refilling. The installer recommends one based on the unit, pipe run and how exposed the site is.
How far can a monobloc unit be from the house?
Usually as close as practical, because water pipes outside lose heat and need frost protection. Manufacturers set limits on pipe length and size, and longer runs need larger, better-insulated pipes. Most homes site the unit against or near an outside wall close to where the pipes enter. If the only good position is far from the house, a split system may suit better.
What refrigerant do monobloc heat pumps use?
Most use R32 or R290. R290 is propane, a natural refrigerant with a very low global warming impact, and some models use it to reach higher flow temperatures. Because R290 is flammable, manufacturers set clearance zones around the unit from openings such as windows, doors and drains, which the survey takes into account when choosing a position.
Do monobloc heat pumps need an F-gas engineer?
For a typical installation no refrigerant work is needed on site, because the refrigerant circuit is sealed in the outdoor unit at the factory. That is one reason monobloc installs are simpler. If the sealed circuit ever develops a fault or leak, any repair to it must be done by an F-gas certified engineer, as with every refrigerant system.