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.
Houses in Surrey with a rear wall close to the cylinder location usually suit a monobloc unit with a short pipe run. In exposed spots around Surrey, frost protection for the outdoor pipework is chosen with the site in mind. Bungalows in Surrey often let the unit sit right beside the plant cupboard, keeping water pipes short.
Who it suits
- Houses and bungalows with outdoor space close to where pipes enter the home
- Households that want to keep refrigerant work out of routine servicing
- Homes where the unit can sit within a short pipe run of the cylinder
- Owners who want the simplest installation, with no indoor refrigerant
Grants and rules for heat pumps in England
Homes in Surrey can use the Boiler Upgrade Scheme, which takes £7,500 off the cost of an air source heat pump when it replaces fossil-fuel or electric heating. Replacing oil or LPG heating qualifies for £9,000 for installations from 21 July 2026 to 31 March 2027, and air-to-air systems for £2,500. The MCS-certified installer named in your quote applies for the grant and deducts it from the price.
There is no VAT on installing a heat pump anywhere in the UK until 31 March 2027. In England most houses can have an air source heat pump under permitted development, provided the unit meets the MCS noise and siting standards; the old 1 m boundary limit was removed on 29 May 2025. We flag listed buildings, flats and sensitive conservation-area positions at survey.
Monobloc heat pumps prices in Surrey
These are guide prices for Surrey, 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 | £10,150–£13,400 | £2,650–£5,900 |
| 2–3 bedroom terrace or semi | 5–7 kW | £11,250–£14,450 | £3,750–£6,950 |
| 3 bedroom semi or small detached | 6–9 kW | £12,850–£16,600 | £5,350–£9,100 |
| 4 bedroom detached | 8–12 kW | £15,000–£19,250 | £7,500–£11,750 |
| 5+ bedroom or larger older house | 11–16 kW | £17,650–£24,100 | £10,150–£16,600 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning.
Towns we cover in Surrey
We cover 14 towns in Surrey for monobloc heat pumps. Each links to local guide prices and the grant position for England.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Woking | GU22 | Guildford | 7 h 51 min |
| Guildford | GU1 | Godalming | 7 h 52 min |
| Redhill | RH1 | Reigate | 7 h 52 min |
| Farnham | GU9 | Aldershot | 7 h 52 min |
| Camberley | GU15 | Sandhurst | 7 h 51 min |
| Egham | TW20 | Woking | 7 h 50 min |
| Godalming | GU7 | Guildford | 7 h 53 min |
| Reigate | RH2 | Redhill | 7 h 52 min |
| Horley | RH6 | Redhill | 7 h 53 min |
| Dorking | RH4 | Reigate | 7 h 52 min |
| Haslemere | GU27 | Godalming | 7 h 54 min |
| Cobham | KT11 | Woking | 7 h 51 min |
| Cranleigh | GU6 | Godalming | 7 h 53 min |
| Oxted | RH8 | Westerham | 7 h 52 min |
Monobloc heat pumps questions
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.
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.
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.