STIEBEL ELTRONWPL-A 17.2 Trend HK 400
The STIEBEL ELTRON WPL-A 17.2 Trend HK 400 is an air-to-water heat pump with a SCOP of 4.55 (35 °C) and a sound power level of 52 dB(A). Under permitted development the limit is 37 dB(A) measured 1 m in front of the centre of a neighbour’s habitable-room door or window. Free-standing, the indicative minimum distance is 2.2 m; against a wall 3.2 m.1,2
Key figures
Rules in the UK
Minimum distance to your neighbour
MCS 020(a) (England, permitted development since 29 May 2025)3 · 1 m in front of the centre of a neighbour’s habitable-room door or window
Indicative calculation (hemispherical, no barriers). Not a substitute for an MCS 020 assessment.
Boiler Upgrade Scheme
Check conditions£7,500 – £9,0004Fixed 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.5,6
- Must be MCS-certified (product and installer). Check the Ofgem product eligibility list.
- Rated output 20.29 kW; the scheme covers systems up to 45 kW.
- SCOP at 55 °C: 3.83. The installed system needs a SCOP of at least 2.8 (MCS calculation).
Technical specifications
| General | |
|---|---|
| Type (source) | Air-to-water1 |
| Compressors | 11 |
| Capacity control | drehzahlregelung1 |
| Performance | |
| Heating capacity (A7/W35) | 7.96 kW2 |
| Rated output 35 °C | 20.29 kW1 |
| Rated output 55 °C | 20.25 kW1 |
| Min. outdoor temperature | -22 °C2 |
| Efficiency | |
| SCOP (35 °C) | 4.551 |
| SCOP (55 °C) | 3.831 |
| Seasonal efficiency ηs 35 °C | 179 %1 |
| Seasonal efficiency ηs 55 °C | 150 %1 |
| Energy label 35 °C | A, , , 2 |
| Energy label 55 °C | A, , , 2 |
| COP A7/W35 | 5.291 |
| COP A2/W35 | 3.911 |
| COP A-7/W35 | 2.621 |
| Noise | |
| Outdoor unit sound power | 52 dB(A)1 |
| Refrigerant | |
| Refrigerant | R2901 |
| Refrigerant GWP | 32 |
| Refrigerant charge | 2.15 kg1 |
| Electrical | |
| Max. power input | 10.19 kW1 |
| Connectivity & smart | |
| SG Ready | Yes1 |
Manufacturer documentation
- Product page
- Datasheet / specifications — WPL-A 07.2 Trend HK 230 – Technisches Datenblatt
External links to STIEBEL ELTRON's official website. The manufacturer may change or move documents; where they differ, the manufacturer's latest version applies.
Compare with
Frequently asked questions
Can I install the STIEBEL ELTRON WPL-A 17.2 Trend HK 400 without planning permission?
Under MCS 020(a) (England, permitted development since 29 May 2025) the unit must not exceed 37 dB(A) 1 m in front of the centre of a neighbour’s habitable-room door or window. With a sound power of 52 dB(A) that indicatively means 2.2 m free-standing, 3.2 m against a wall or 4.5 m in a corner. Your MCS installer must confirm this.1,2
How much Boiler Upgrade Scheme grant can you get for the STIEBEL ELTRON WPL-A 17.2 Trend HK 400?
£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 27 Sept 2026
- Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 Sept 2026
- MCS 020(a) (England, permitted development since 29 May 2025)
- 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