Nibe S1255 (3–12 kW)

Specifications and technical data

Also known as: S1255-12 1x230, NIBE S1255-12

✓ BUS eligibleGround Source (GSHP)ResidentialR407C3–12 kW

Manufacturer	Nibe
Model	S1255
Model code	S1255-12
Heat pump type	Ground Source (GSHP) All Ground Source heat pumps →
Application	Residential All Residential heat pumps →
Refrigerant	R407C All R407C heat pumps →
Mode	Heating only
Heating capacity	3–12 kW
Max heating output (low temp)	5.06 kW at B0/W35
COP (heating)	4.87 at B0/W35
SCOP (heating)	5.2 at W35
Operating range (air)	-8 to 30 °C
Heating flow temperature	20–70 °C
Electrical supply	220-240V (Single Phase)
Dimensions (H×W×D)	1800 × 600 × 620 mm
Operational Weight	213 kg
Sound power level	47 dB(A) (Sound Power LW(A))
Data added	2026-09-24
Data source	Manufacturer installer manual (Nibe)
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.	012-SC0191-19-2
MCS certification	✓ MCS listed
MCS certificate no.	012-SC0191-19-2

Free data sheet (PDF) →

NIBE S1255-12, inverter-controlled ground source heat pump with an integrated 173 litre hot water cylinder, R407C. Modulates 3 to 12 kW; 5.06 kW at B0/W35 with a COP of 4.87, SCOP 5.2 at W35 and 4.1 at W55 (A+++ / A+++). Flow to 70 C. Sound power up to 47 dB(A). Single-phase.

Where to buy (UK)

UK Supplier	Baxter Heat Pumps
UK Supplier	IMS Heat Pumps

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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.