Heat pumps · UK

ThermiaLegend 13 Duo 400V

The Thermia Legend 13 Duo 400V is a heat pump with SCOP (35 °C) 6.2 and refrigerant R452B.1

Key figures

SCOP (35 °C)
6.21

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

Refrigerant
R452B1
Official source
Type (source)
Ground source1
Official source
Rated output 35 °C
16.92kW1
Official source
Rated output 55 °C
18.3kW1
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 16.92 kW; the scheme covers systems up to 45 kW.
  • SCOP at 55 °C: 4.78. 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 16.92 kW1
Rated output 55 °C 18.3 kW1
Efficiency
SCOP (35 °C) 6.21
SCOP (55 °C) 4.781
Seasonal efficiency ηs 35 °C 240 %1
Seasonal efficiency ηs 55 °C 183 %1
Energy label 35 °C A, , , 1
Energy label 55 °C A, , , 1
Noise
Indoor unit sound power 45 dB(A)1
Refrigerant
Refrigerant R452B1
Refrigerant GWP 6981
Refrigerant charge 1 kg1

Manufacturer documentation

External links to Thermia'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 Thermia Legend 13 Duo 400V?

The SCOP (35 °C) of the Thermia Legend 13 Duo 400V is 6.2.1

Which refrigerant does the Thermia Legend 13 Duo 400V use?

The refrigerant of the Thermia Legend 13 Duo 400V is R452B.1

How much Boiler Upgrade Scheme grant can you get for the Thermia Legend 13 Duo 400V?

£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