Stiebel Eltron WPL ACS classic (4.06 kW)

Specifications and technical data

✓ BUS eligibleAir Source (ASHP)ResidentialR410A4.06 kW

Manufacturer	Stiebel Eltron
Model	WPL ACS classic
Model code	WPL 09 ACS classic
Heat pump type	Air Source (ASHP) All Air Source heat pumps →
Application	Residential All Residential heat pumps →
Refrigerant	R410A All R410A heat pumps →
Mode	Heating & cooling
Heating capacity	4.06 kW
Max heating output (low temp)	4.06 kW at A-7/W35
COP (heating)	4.54 at A7/W35
SCOP (heating)	4.15 at W35
Operating range (air)	-20 to 40 °C
Heating flow temperature	up to 60 °C
Electrical supply	220-240V (Single Phase)
Dimensions (H×W×D)	740 × 1022 × 524 mm
Operational Weight	62 kg
Sound power level	52 dB(A) (Sound Power LW(A))
Data added	2026-09-14
Data source	Manufacturer documentation (Stiebel Eltron)
Verification	Verified by a human
Boiler Upgrade Scheme	✓ BUS eligible — Listed on the Ofgem BUS Product Eligibility List (24 Sep 2026). Grant also needs an MCS-certified installer and a qualifying system design. Funding guide
PEL certificate no.	011-1W0061_1

Free data sheet (PDF) →

Check noise at a neighbour’s window (MCS 020 a) →

Stiebel Eltron WPL 09 ACS classic air-to-water heat pump. Inverter technology, R410A refrigerant, 230 V single-phase compressor. Energy efficiency class A++ at W35 and A+ at W55. Sound power 52 dB(A) to EN 12102, with a Silent Mode for further reduction. The ACS designation denotes the cooling function.

Where to buy (UK)

UK Supplier	Midsummer Wholesale
UK Supplier	Heat Pump Central

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Data is compiled from manufacturer sources and may contain errors or gaps. Always confirm specifications with the manufacturer before making decisions.