Stiebel Eltron HPA-O CS Plus (1.3–4.5 kW)

Specifications and technical data

Also known as: HPA-O 4 CS Plus

✓ BUS eligibleAir Source (ASHP)ResidentialR410A1.3–4.5 kW

Manufacturer	Stiebel Eltron
Model	HPA-O CS Plus
Model code	HPA-O 04 CS Plus Int
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	1.3–4.5 kW
Max heating output (low temp)	4.06 kW at A-7/W35
COP (heating)	4.7 at A7/W35
SCOP (heating)	4.15 at W35
Operating range (air)	-20 to 40 °C
Heating flow temperature	15–60 °C
Electrical supply	220-240V (Single Phase)
Cooling capacity	1.5 kW
Max cooling output (high temp)	1.5 kW at A35/W7
Dimensions (H×W×D)	740 × 1022 × 524 mm
Operational Weight	62 kg
Sound power level	52 dB(A) (Sound Power LW(A))
Data added	2026-10-21
Data source	Stiebel Eltron HPA-O CS Plus operation and installation manual (doc-00083293)
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.	011-1W0283
MCS certification	✓ MCS listed
MCS certificate no.	011-1W0283

Free data sheet (PDF) →

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

Stiebel Eltron HPA-O 4 CS Plus R410A inverter air-to-water monobloc heat pump for outdoor installation, heating and cooling, flow up to 60 °C, operation down to -20 °C, single-phase 230 V.

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.