STIEBEL ELTRON WPW-I 12 H 400 Premium
The STIEBEL ELTRON WPW-I 12 H 400 Premium is a heat pump with SCOP (35 °C) 6.3 and refrigerant R410A.1,2
Key figures
Rules in the UK
Boiler Upgrade Scheme
Check conditions£7,500 – £9,0003Fixed 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.4,5
- Must be MCS-certified (product and installer). Check the Ofgem product eligibility list.
- Rated output 14 kW; the scheme covers systems up to 45 kW.
- SCOP at 55 °C: 4.1. The installed system needs a SCOP of at least 2.8 (MCS calculation).
Technical specifications
| General | |
|---|---|
| Type (source) | Water-to-water1 |
| Compressors | 11 |
| Capacity control | keine1 |
| Performance | |
| Rated output 35 °C | 14 kW2 |
| Rated output 55 °C | 12 kW2 |
| Efficiency | |
| SCOP (35 °C) | 6.32 |
| SCOP (55 °C) | 4.12 |
| Seasonal efficiency ηs 35 °C | 249 %2 |
| Seasonal efficiency ηs 55 °C | 161 %2 |
| Energy label 35 °C | A+++2 |
| Energy label 55 °C | A+++2 |
| Noise | |
| Indoor unit sound power | 46 dB(A)2 |
| Refrigerant | |
| Refrigerant | R410A1 |
| Refrigerant charge | 2.95 kg1 |
| Electrical | |
| Max. power input | 4.9 kW1 |
| Connectivity & smart | |
| SG Ready | Yes1 |
How it ranks
SCOP (35 °C): better than 47% of comparable models in our database (Heat pumps · Water-to-water · ≥ 14 kW; n = 65).
Rank 33 of 66
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.
Similar models
Other brands, same type and a comparable size.
More from STIEBEL ELTRON
- STIEBEL ELTRON WPE-I 13 H 400 Plus SCOP (35 °C): 3.65
- STIEBEL ELTRON WPE-I 15 HW 230 Premium SCOP (35 °C): 5.33
- STIEBEL ELTRON WPL-A 13.2 Trend HK 400 SCOP (35 °C): 4.65
- STIEBEL ELTRON WPL-A 13 HK 400 Premium SCOP (35 °C): 4.35
- STIEBEL ELTRON HPG-I 15 (D)(C)S Premium SCOP (35 °C): 5.44
- STIEBEL ELTRON WPE-I 15 H 230 Premium SCOP (35 °C): 5.33
Guides on heat pumps
- SCOP, COP and ηs: what a heat pump’s efficiency figures mean
- Hybrid or full heat pump? The main types compared
- Heat pump noise: MCS 020(a), permitted development and where to put the unit
- Sizing a heat pump: heat loss, flow temperature and rated output
- Heat pump refrigerants: R290, R32 and R410A compared
How we collect and check this data →
Frequently asked questions
What is the SCOP (35 °C) of the STIEBEL ELTRON WPW-I 12 H 400 Premium?
The SCOP (35 °C) of the STIEBEL ELTRON WPW-I 12 H 400 Premium is 6.3.1,2
Which refrigerant does the STIEBEL ELTRON WPW-I 12 H 400 Premium use?
The refrigerant of the STIEBEL ELTRON WPW-I 12 H 400 Premium is R410A.1,2
How much Boiler Upgrade Scheme grant can you get for the STIEBEL ELTRON WPW-I 12 H 400 Premium?
£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
Sources
- List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 18 Oct 2026
- European Product Registry for Energy Labelling (EPREL) – heat pumps — Europese Commissie · accessed 15 Oct 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