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.
In exposed spots around Devon, frost protection for the outdoor pipework is chosen with the site in mind. Houses in Devon with a rear wall close to the cylinder location usually suit a monobloc unit with a short pipe run. For Devon terraces with small yards, the survey confirms the unit fits with the clearances it needs.
Who it suits
- Owners who want the simplest installation, with no indoor refrigerant
- 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
- Households that want to keep refrigerant work out of routine servicing
Grants and rules for heat pumps in England
In England 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), and since 28 April 2026 a valid EPC is no longer needed. The grant is applied for by the MCS-certified installer and shown as a deduction on your quote.
Installing heat pumps is zero-rated for VAT across the UK until 31 March 2027. Since 29 May 2025, permitted development in England allows up to two air source heat pumps on a house, each up to 1.5 m³, with no blanket 1 m boundary rule — the installation must still meet the MCS planning standards, including the noise check. Listed buildings, flats and some conservation-area positions need extra consent, which we check at survey.
Monobloc heat pumps prices in Devon
These are guide prices for Devon, 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 | £9,600–£12,650 | £2,100–£5,150 |
| 2–3 bedroom terrace or semi | 5–7 kW | £10,600–£13,650 | £3,100–£6,150 |
| 3 bedroom semi or small detached | 6–9 kW | £12,100–£15,650 | £4,600–£8,150 |
| 4 bedroom detached | 8–12 kW | £14,150–£18,200 | £6,650–£10,700 |
| 5+ bedroom or larger older house | 11–16 kW | £16,650–£22,750 | £9,150–£15,250 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning.
Towns we cover in Devon
We cover 18 towns in Devon for monobloc heat pumps. Each links to local guide prices and the grant position for England.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Plymouth | PL1 | Saltash | 8 h 01 min |
| Exeter | EX4 | Crediton | 7 h 57 min |
| Paignton | TQ3 | Torquay | 8 h 00 min |
| Torquay | TQ1 | Paignton | 8 h 00 min |
| Newton Abbot | TQ12 | Torquay | 7 h 59 min |
| Exmouth | EX8 | Sidmouth | 7 h 58 min |
| Barnstaple | EX31 | Bideford | 7 h 54 min |
| Bideford | EX39 | Barnstaple | 7 h 54 min |
| Tiverton | EX16 | Crediton | 7 h 56 min |
| Crediton | EX17 | Exeter | 7 h 57 min |
| Dartmouth | TQ6 | Paignton | 8 h 01 min |
| Honiton | EX14 | Sidmouth | 7 h 57 min |
| Ilfracombe | EX34 | Barnstaple | 7 h 52 min |
| Kingsbridge | TQ7 | Dartmouth | 8 h 02 min |
| Okehampton | EX20 | Tavistock | 7 h 57 min |
| Sidmouth | EX10 | Honiton | 7 h 58 min |
| Tavistock | PL19 | Plymouth | 7 h 59 min |
| Totnes | TQ9 | Paignton | 8 h 00 min |
Monobloc heat pumps questions
Are monobloc heat pumps covered by grants?
Yes. Monobloc units are air-to-water heat pumps, so in England and Wales they are covered by the Boiler Upgrade Scheme grant of £7,500 for eligible homes, or £9,000 when replacing oil or LPG heating within the published dates. In Scotland, Home Energy Scotland funding requires an MCS-certified installer and products. There is no dedicated homeowner heat pump grant in Northern Ireland at present.
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.
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.
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.