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Heat pumps · UK

Bosch Compress CS5800iAW 4 ORMB-S (AW 4 OR-S + CS5800iAW 12 MB)

Bosch Compress CS5800iAW 4 ORMB-S (AW 4 OR-S + CS5800iAW 12 MB)
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The Bosch Compress CS5800iAW 4 ORMB-S (AW 4 OR-S + CS5800iAW 12 MB) is an air-to-water heat pump with a SCOP of 4.55 (35 °C) and a sound power level of 40 dB(A). Under permitted development the limit is 37 dB(A) measured 1 m in front of the centre of a neighbour’s habitable-room door or window. Free-standing, the indicative minimum distance is 0.6 m; against a wall 0.8 m.1

Last updated: Technical specificationsRules in the UK⇄ Compare this model
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SCOP (35 °C)
4.551

Seasonal efficiency: how much heat you get per kWh of electricity across a heating season.

Outdoor unit sound power
40dB(A)1
Official source
Refrigerant
R2901
Official source
Type (source)
Air-to-water1
Official source
Rated output 35 °C
4.4kW1
Official source
UK

Rules in the UK

Minimum distance to your neighbour

MCS 020(a) (England, permitted development since 29 May 2025)2 · 1 m in front of the centre of a neighbour’s habitable-room door or window

Permitted development (MCS 020(a))≤ 37 dB(A) · LAeq,5min
Free-standing0.6 m
Against wall0.8 m
In corner1.1 m

Indicative calculation (hemispherical, no barriers). Not a substitute for an MCS 020 assessment.

Boiler Upgrade Scheme

Check conditions

£7,500 – £9,0003Fixed grant (England & Wales)

Fixed grant in England and Wales, deducted from your installer’s quote. £9,000 when replacing oil or LPG off the gas grid (until March 2027). Scotland: Home Energy Scotland grant instead.4,5

  • Must be MCS-certified (product and installer). Check the Ofgem product eligibility list.
  • Rated output 4.4 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 3.28. The installed system needs a SCOP of at least 2.8 (MCS calculation).
Heat pump grants in the UK explained →

Technical specifications

General
Type (source)Air-to-water1
Compressors11
Capacity controldrehzahlregelung1
Performance
Rated output 35 °C4.4 kW1
Rated output 55 °C4 kW1
Efficiency
SCOP (35 °C)4.551
SCOP (55 °C)3.281
Seasonal efficiency ηs 35 °C179 %1
Seasonal efficiency ηs 55 °C128 %1
COP A7/W354.821
COP A2/W353.911
COP A-7/W352.881
SEER (cooling)2.361
Noise
Outdoor unit sound power40 dB(A)1
Indoor unit sound power37 dB(A)1
Refrigerant
RefrigerantR2901
Refrigerant charge0.95 kg1
Electrical
Max. power input3.2 kW1
Connectivity & smart
SG ReadyYes1

How it ranks

SCOP (35 °C): better than 20% of comparable models in our database (Heat pumps · Air-to-water · 4–6 kW; n = 122).

Rank 91 of 123

Compared with every model on VersusIndex in the same group with a known value; equal values do not count as better. This says nothing about price, installation or reliability.

Manufacturer documentation

  • Product page (bosch-homecomfort.com)
  • Brochure / leaflet — Broschüre Bosch Wärmepumpe Compress 5800i AW / 6800i AW (bosch-homecomfort.com, PDF)
  • Manual — Bedienungsanleitung Luft-/Wasserwärmepumpe Compress 5800iAW | 6800iAW (docs.bosch-homecomfort.com, PDF)
  • Manual — Installationsanleitung Inneneinheit Compress 5800i AW (bosch-de-de.boschhc-documents.com, PDF)

External links to Bosch's official website. The manufacturer may change or move documents; where they differ, the manufacturer's latest version applies.

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Frequently asked questions

Can I install the Bosch Compress CS5800iAW 4 ORMB-S (AW 4 OR-S + CS5800iAW 12 MB) without planning permission?

Under MCS 020(a) (England, permitted development since 29 May 2025) the unit must not exceed 37 dB(A) 1 m in front of the centre of a neighbour’s habitable-room door or window. With a sound power of 40 dB(A) that indicatively means 0.6 m free-standing, 0.8 m against a wall or 1.1 m in a corner. Your MCS installer must confirm this.1

How much Boiler Upgrade Scheme grant can you get for the Bosch Compress CS5800iAW 4 ORMB-S (AW 4 OR-S + CS5800iAW 12 MB)?

£7,500 in England and Wales, provided the product and installer are MCS-certified (£9,000 when replacing oil or LPG off the gas grid, until March 2027). The installer applies and deducts the grant from your quote.1

Which refrigerant does the Bosch Compress CS5800iAW 4 ORMB-S (AW 4 OR-S + CS5800iAW 12 MB) use?

The Bosch Compress CS5800iAW 4 ORMB-S (AW 4 OR-S + CS5800iAW 12 MB) uses R290.1

Sources

  1. List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026
  2. MCS 020(a) (England, permitted development since 29 May 2025)
  3. Boiler Upgrade Scheme: what you can get — GOV.UK · accessed 27 Sept 2026
  4. Boiler Upgrade Scheme: guidance for installers (V5) — Ofgem · accessed 27 Sept 2026
  5. Boiler Upgrade Scheme product eligibility — Ofgem · accessed 27 Sept 2026