Heat Pump Sizing for 124 m² (1,335 sq ft) — Central Europe / DACH (-12°C Design, DE/CH/AT/NL)
Thermal heat loss calculation, recommended heat pump capacity (kW, BTU/h & HVAC Tons), SCOP efficiency, and annual electricity consumption.
Recommended Heat Pump12.7 kW43,334 BTU/h (3.61 Tons)
Annual Electricity Usage6,692 kWh/yrDelivers 25,431 kWh Heat (SCOP 3.8)
Savings vs Direct Electric18,739 kWh/yrSpecific Load: 97.7 W/m²
Electrical Circuit (230V)25 A BreakerPeak Compressor Input: 4.23 kW
Thermal & Electrical Specification Table (124 m² / 1,335 sq ft)
| Heated Floor Area | 124 m² (1,335 sq ft) |
| Climate Zone & Design Outdoor Temp | Central Europe / DACH (-12°C Design, DE/CH/AT/NL) |
| Building Insulation Envelope | Older Uninsulated Building (85 W/m² Base) (97.7 W/m² Peak) |
| Peak Space Heating Load | 12.11 kW Thermal |
| Recommended Heat Pump Output (Incl. DHW) | 12.7 kW (43,334 BTU/h · 3.61 Tons) |
| Seasonal Coefficient of Performance (SCOP) | 3.8 (340%–450% Seasonal Efficiency) |
| Annual Heat Demand vs Electricity Consumed | 25,431 kWh Heat → 6,692 kWh Electricity |
Frequently Asked Questions
What kW size heat pump do I need for a 124 m² (1335 sq ft) house?
For a 124 m² (1335 sq ft) building with Older Uninsulated Building (85 W/m² Base) in Central Europe / DACH (-12°C Design, DE/CH/AT/NL), the peak space heating load is 12.11 kW (97.7 W/m²). Including domestic hot water allowance, a 12.7 kW (43,334 BTU/h / 3.61 Ton) heat pump is recommended.
How many kWh of electricity does a 12.7 kW heat pump use per year?
With a Seasonal Coefficient of Performance (SCOP) of 3.8 over 2100 full-load equivalent heating hours, the heat pump consumes approximately 6,692 kWh of electricity per year to deliver 25,431 kWh of heat — saving 18,739 kWh/year compared to direct electric radiators.
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