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Heat pumps · UK

STIEBEL ELTRONWPF 20

STIEBEL ELTRON WPF 20
Image: STIEBEL ELTRONrequest removal

The STIEBEL ELTRON WPF 20 is a heat pump with SCOP (35 °C) 5 and refrigerant R410A.1

Last updated: Technical specifications Rules in the UK ⇄ Compare this model
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SCOP (35 °C)
51

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

Refrigerant
R410A1
Official source
Type (source)
Ground source1
Official source
Rated output 35 °C
22kW1
Official source
Rated output 55 °C
20kW1
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 22 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 3.48. 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) Ground source1
Performance
Rated output 35 °C 22 kW1
Rated output 55 °C 20 kW1
Efficiency
SCOP (35 °C) 51
SCOP (55 °C) 3.481
Seasonal efficiency ηs 35 °C 192 %1
Seasonal efficiency ηs 55 °C 131 %1
Energy label 35 °C A, , , 1
Energy label 55 °C A, , 1
Noise
Indoor unit sound power 59 dB(A)1
Refrigerant
Refrigerant R410A1
Refrigerant GWP 2,0881
Refrigerant charge 5.99 kg1

Manufacturer documentation

External links to STIEBEL ELTRON'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 STIEBEL ELTRON WPF 20?

The SCOP (35 °C) of the STIEBEL ELTRON WPF 20 is 5.1

Which refrigerant does the STIEBEL ELTRON WPF 20 use?

The refrigerant of the STIEBEL ELTRON WPF 20 is R410A.1

How much Boiler Upgrade Scheme grant can you get for the STIEBEL ELTRON WPF 20?

£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. Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 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