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Heat pumps · UK

NIBE S2125-14

NIBE S2125-14
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The NIBE S2125-14 is an air-to-water heat pump with a SCOP of 5.27 (35 °C) and a sound power level of 52 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 2.2 m; against a wall 3.2 m.1,2

Last updated: Technical specificationsRules in the UK⇄ Compare this model
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SCOP (35 °C)
5.271

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

Outdoor unit sound power
52dB(A)1
Official source
Refrigerant
R2901
Official source
Type (source)
Air-to-water1
Official source
Rated output 35 °C
11kW1
Official source
UK

Rules in the UK

Minimum distance to your neighbour

MCS 020(a) (England, permitted development since 29 May 2025)3 · 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-standing2.2 m
Against wall3.2 m
In corner4.5 m

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

Boiler Upgrade Scheme

Check conditions

£7,500 – £9,0004Fixed 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.5,6

  • Must be MCS-certified (product and installer). Check the Ofgem product eligibility list.
  • Rated output 11 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 4.05. 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 controlInverter1
Performance
Rated output 35 °C11 kW1
Rated output 55 °C11 kW1
Efficiency
SCOP (35 °C)5.271
SCOP (55 °C)4.051
Seasonal efficiency ηs 35 °C208 %1
Seasonal efficiency ηs 55 °C159 %1
Energy label 35 °CA+++2
Energy label 55 °CA+++2
COP A7/W355.551
COP A2/W354.661
COP A-7/W353.41
Noise
Outdoor unit sound power52 dB(A)1
Indoor unit sound power52 dB(A)1
Refrigerant
RefrigerantR2901
Refrigerant charge1.15 kg1
Electrical
Max. power input5 kW1
Connectivity & smart
SG ReadyYes1

How it ranks

SCOP (35 °C): better than 92% of comparable models in our database (Heat pumps · Air-to-water · 10–14 kW; n = 308).

Rank 25 of 309

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.

Variants

This model is registered in 2 combinations (for example with a different indoor unit or cylinder) with exactly the same performance. All figures on this page apply to each of these types. The part of the type number that differs is in bold; small differences (e.g. cylinder volume or anode) are listed after it:

  • S2125-14
  • S2125-14

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Frequently asked questions

Can I install the NIBE S2125-14 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 52 dB(A) that indicatively means 2.2 m free-standing, 3.2 m against a wall or 4.5 m in a corner. Your MCS installer must confirm this.1,2

How much Boiler Upgrade Scheme grant can you get for the NIBE S2125-14?

£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.1,2

Which refrigerant does the NIBE S2125-14 use?

The NIBE S2125-14 uses R290.1,2

Sources

  1. List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026
  2. European Product Registry for Energy Labelling (EPREL) – heat pumps — Europese Commissie · accessed 15 Oct 2026
  3. MCS 020(a) (England, permitted development since 29 May 2025)
  4. Boiler Upgrade Scheme: what you can get — GOV.UK · accessed 27 Sept 2026
  5. Boiler Upgrade Scheme: guidance for installers (V5) — Ofgem · accessed 27 Sept 2026
  6. Boiler Upgrade Scheme product eligibility — Ofgem · accessed 27 Sept 2026