Heat pumps · UK

STIEBEL ELTRON LWZ 05.1 Premium HKWL 230

The STIEBEL ELTRON LWZ 05.1 Premium HKWL 230 is an air-to-water heat pump with a SCOP of 4.28 (35 °C) and a sound power level of 55 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 3.2 m; against a wall 4.5 m.^1,2,3,4

Last updated: 15 October 2026Technical specifications Rules in the UK ⇄ Compare this model

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SCOP (35 °C): 4.28⁴
Seasonal efficiency: how much heat you get per kWh of electricity across a heating season.
Heating capacity (A7/W35): 2.26kW³
Official source
Outdoor unit sound power: 55dB(A)⁴
Official source
Refrigerant: R290¹
Official source
Type (source): Air-to-water¹
Official source

Rules in the UK

Minimum distance to your neighbour

MCS 020(a) (England, permitted development since 29 May 2025)⁵ · 1 m in front of the centre of a neighbour’s habitable-room door or window

Permitted development (MCS 020(a))≤ 37 dB(A) · LAeq,5min

Free-standing3.2 m

Against wall4.5 m

In corner6.3 m

Indicative calculation (hemispherical, no barriers). Not a substitute for an MCS 020 assessment.

Boiler Upgrade Scheme

Check conditions

£7,500 – £9,000⁶Fixed 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.^7,8

Must be MCS-certified (product and installer). Check the Ofgem product eligibility list.
Rated output 5 kW; the scheme covers systems up to 45 kW.
SCOP at 55 °C: 3.28. 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)	Air-to-water¹
Compressors	1¹
Capacity control	Inverter¹
Performance
Heating capacity (A7/W35)	2.26 kW³
Rated output 35 °C	5 kW⁴
Rated output 55 °C	5 kW⁴
Efficiency
SCOP (35 °C)	4.28⁴
SCOP (55 °C)	3.28⁴
Seasonal efficiency ηs 35 °C	168 %⁴
Seasonal efficiency ηs 55 °C	128 %⁴
Energy label 35 °C	A++⁴
Energy label 55 °C	A++⁴
COP A7/W35	5.55¹
COP A2/W35	4.14¹
COP A-7/W35	2.9¹
Noise
Outdoor unit sound power	55 dB(A)⁴
Indoor unit sound power	53 dB(A)⁴
Refrigerant
Refrigerant	R290¹
Refrigerant GWP	3³
Refrigerant charge	1.24 kg¹
Electrical
Max. power input	12.2 kW¹
Connectivity & smart
SG Ready	Yes¹
Grants & market
ISDE grant (NL)	2,150 €²

How it ranks

SCOP (35 °C): better than 3% of comparable models in our database (Heat pumps · Air-to-water · 4–6 kW; n = 122).

Rank 116 of 123

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.

Manufacturer documentation

Product page (stiebel-eltron.ch)
Datasheet / specifications — LWZ 07.1 Premium HKWL 230 – Technisches Datenblatt (stiebel-eltron.ch, PDF)

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

Similar models

Other brands, same type and a comparable size.

Guides on heat pumps

How we collect and check this data →

Frequently asked questions

Can I install the STIEBEL ELTRON LWZ 05.1 Premium HKWL 230 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 55 dB(A) that indicatively means 3.2 m free-standing, 4.5 m against a wall or 6.3 m in a corner. Your MCS installer must confirm this.^1,2,3,4

How much Boiler Upgrade Scheme grant can you get for the STIEBEL ELTRON LWZ 05.1 Premium HKWL 230?

£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.^1,2,3,4

Which refrigerant does the STIEBEL ELTRON LWZ 05.1 Premium HKWL 230 use?

The STIEBEL ELTRON LWZ 05.1 Premium HKWL 230 uses R290.^1,2,3,4

Sources

List of eligible heat pumps (BEG) — Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) · accessed 27 Sept 2026
ISDE heat pump notification code list — Rijksdienst voor Ondernemend Nederland (RVO) · accessed 28 Sept 2026
Heat Pump Keymark certificates — EHPA / DIN CERTCO (Heat Pump KEYMARK) · accessed 29 Sept 2026
European Product Registry for Energy Labelling (EPREL) – heat pumps — Europese Commissie · accessed 15 Oct 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

Key figures