ThermiaLegend 17 Duo 400V
The Thermia Legend 17 Duo 400V is a heat pump with SCOP (35 °C) 5.51 and refrigerant R452B.1
Key figures
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 21.73 kW; the scheme covers systems up to 45 kW.
- SCOP at 55 °C: 4.64. The installed system needs a SCOP of at least 2.8 (MCS calculation).
Technical specifications
| General | |
|---|---|
| Type (source) | Ground source1 |
| Performance | |
| Rated output 35 °C | 21.73 kW1 |
| Rated output 55 °C | 24.86 kW1 |
| Efficiency | |
| SCOP (35 °C) | 5.511 |
| SCOP (55 °C) | 4.641 |
| Seasonal efficiency ηs 35 °C | 213 %1 |
| Seasonal efficiency ηs 55 °C | 178 %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 | 1.7 kg1 |
Manufacturer documentation
- Datasheet / specifications — Thermia Legend Datasheet
- Brochure / leaflet — Thermia Legend brochure voor eindgebruikers
- Manual — Thermia Legend Gebruikershandleiding
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 17 Duo 400V?
The SCOP (35 °C) of the Thermia Legend 17 Duo 400V is 5.51.1
Which refrigerant does the Thermia Legend 17 Duo 400V use?
The refrigerant of the Thermia Legend 17 Duo 400V is R452B.1
How much Boiler Upgrade Scheme grant can you get for the Thermia Legend 17 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
- Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 Sept 2026
- Boiler Upgrade Scheme: what you can get — GOV.UK · accessed 27 Sept 2026
- Boiler Upgrade Scheme: guidance for installers (V5) — Ofgem · accessed 27 Sept 2026
- Boiler Upgrade Scheme product eligibility — Ofgem · accessed 27 Sept 2026