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Heat pumps · UK

Mareli SystemsFGS 10MB

The Mareli Systems FGS 10MB is an air-to-water heat pump with a SCOP of 4.84 (35 °C) and a sound power level of 59.2 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 5.1 m; against a wall 7.3 m.1

Last updated: Technical specifications Rules in the UK
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SCOP (35 °C)
4.841

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

Outdoor unit sound power
59.2dB(A)1
Official source
Refrigerant
R321
Official source
Rated output 35 °C
8kW1
Official source
Rated output 55 °C
7.3kW1
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-standing 5.1 m
Against wall 7.3 m
In corner 10.3 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 8 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 3.58. The installed system needs a SCOP of at least 2.8 (MCS calculation).
Heat pump grants in the UK explained →

Technical specifications

General
Type Air-to-water1
Compressors 11
Capacity control Inverter1
Performance
Rated output 35 °C 8 kW1
Rated output 55 °C 7.3 kW1
Efficiency
SCOP (35 °C) 4.841
SCOP (55 °C) 3.581
Seasonal efficiency ηs 35 °C 190.42 %1
Seasonal efficiency ηs 55 °C 140.13 %1
COP A7/W35 4.831
COP A2/W35 4.751
COP A-7/W35 3.441
SEER (cooling) 3.71
Noise
Outdoor unit sound power 59.2 dB(A)1
Refrigerant
Refrigerant R321
Refrigerant charge 1.85 kg1
Electrical
Max. power input 3.21 kW1
Connectivity & smart
SG Ready Yes1

Frequently asked questions

Can I install the Mareli Systems FGS 10MB 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 59.2 dB(A) that indicatively means 5.1 m free-standing, 7.3 m against a wall or 10.3 m in a corner. Your MCS installer must confirm this.1

How much Boiler Upgrade Scheme grant can you get for the Mareli Systems FGS 10MB?

£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 Mareli Systems FGS 10MB use?

The Mareli Systems FGS 10MB uses R32.1

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