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SwegonSIGMA Zero Hi OH 25

Swegon SIGMA Zero Hi OH 25
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The Swegon SIGMA Zero Hi OH 25 is a heat pump with SCOP (35 °C) 5.96 and refrigerant R290.1

Last updated: Technical specifications Rules in the UK ⇄ Compare this model
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SCOP (35 °C)
5.961

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

Refrigerant
R2901
Official source
Type (source)
Water-to-water1
Official source
Rated output 35 °C
34kW1
Official source
Rated output 55 °C
31kW1
Official source
UK

Rules in the UK

Boiler Upgrade Scheme

Check conditions

£7,500 – £9,0002Fixed 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.3,4

  • Must be MCS-certified (product and installer). Check the Ofgem product eligibility list.
  • Rated output 34 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 4.55. 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) Water-to-water1
Compressors 11
Capacity control drehzahlregelung1
Performance
Rated output 35 °C 34 kW1
Rated output 55 °C 31 kW1
Efficiency
SCOP (35 °C) 5.961
SCOP (55 °C) 4.551
Seasonal efficiency ηs 35 °C 230 %1
Seasonal efficiency ηs 55 °C 174 %1
Noise
Indoor unit sound power 76.9 dB(A)1
Refrigerant
Refrigerant R2901
Refrigerant charge 0.7 kg1
Electrical
Max. power input 16.5 kW1
Connectivity & smart
SG Ready Yes1

Manufacturer documentation

  • Product page (swegon.com)
  • Brochure / leaflet — SIGMA Zero – Kaltwassererzeuger und Wärmepumpen mit R290, 20–70 kW (Broschüre) (swegon.com, PDF)

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

Frequently asked questions

What is the SCOP (35 °C) of the Swegon SIGMA Zero Hi OH 25?

The SCOP (35 °C) of the Swegon SIGMA Zero Hi OH 25 is 5.96.1

Which refrigerant does the Swegon SIGMA Zero Hi OH 25 use?

The refrigerant of the Swegon SIGMA Zero Hi OH 25 is R290.1

How much Boiler Upgrade Scheme grant can you get for the Swegon SIGMA Zero Hi OH 25?

£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

Sources

  1. List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026
  2. Boiler Upgrade Scheme: what you can get — GOV.UK · accessed 27 Sept 2026
  3. Boiler Upgrade Scheme: guidance for installers (V5) — Ofgem · accessed 27 Sept 2026
  4. Boiler Upgrade Scheme product eligibility — Ofgem · accessed 27 Sept 2026