S1256

NIBE S1256 is a current inverter-driven ground-source heat pump with an integrated 180-litre domestic hot-water cylinder. NIBE’s UK page lists S1256-8 and S1256-13 designations, including variants prepared for passive cooling.

Range and performance

NIBE publishes a SCOP (seasonal coefficient of performance) of up to 6.22 under its stated test basis and A+++ heating energy labels at 35°C and 55°C applications. These are standardised product figures. Actual seasonal performance depends on ground-loop temperature, heating flow temperature, distribution losses, hot-water demand and controls.

The number in an S1256 designation is not a guarantee of output at the coldest source and highest required flow temperature. Selection uses the manufacturer’s capacity table for the exact model at the design condition, compared with the room-by-room heat-loss calculation.

Integrated arrangement

S1256 packages the compressor, controls and hot-water cylinder into one indoor cabinet. This reduces the number of separate major appliances, but does not make the installation self-contained. It still needs a designed borehole, trench or suitable water-source circuit, heating distribution, circulation, expansion, safety and electrical arrangements.

An integrated 180-litre cylinder may or may not match a household’s hot-water demand. Recovery performance, stored temperature, bath or shower pattern and any supplementary heating are part of the design.

Passive cooling depends on the exact variant and installed distribution. It needs controls and condensation protection appropriate to the emitters, pipework and indoor humidity.

Ground-side and heating design

S1256-8 and S1256-13 have separate phase and passive-cooling variants. System selection uses the exact suffix, room heat loss, flow temperature, available model output, hot-water assumptions and any electrical supplementary heater.

Ground-loop sizing uses the assumed geology or source condition, borehole or loop arrangement, extraction rate, antifreeze and pump duty. The ground array must support both the building load and the selected operating pattern.

S-Series controls and myUplink provide monitoring and adjustment. Warranty depends on registration, installer route, servicing and the full NIBE terms. The documentation supplied with the exact unit remains the controlling record.

Related entries

• NIBE
• NIBE S1156
• NIBE S1255
• Ground source heat pumps