Heat Pump Sizing for 604 m² (6,501 sq ft) — UK & Temperate Maritime (-5°C Design, UK/IE/NZ)
Thermal heat loss calculation, recommended heat pump capacity (kW, BTU/h & HVAC Tons), SCOP efficiency, and annual electricity consumption.
Recommended Heat Pump49.4 kW168,560 BTU/h (14.05 Tons)
Annual Electricity Usage21,424 kWh/yrDelivers 87,840 kWh Heat (SCOP 4.1)
Savings vs Direct Electric66,416 kWh/yrSpecific Load: 80.8 W/m²
Electrical Circuit (230V)90 A BreakerPeak Compressor Input: 14.97 kW
Thermal & Electrical Specification Table (604 m² / 6,501 sq ft)
| Heated Floor Area | 604 m² (6,501 sq ft) |
| Climate Zone & Design Outdoor Temp | UK & Temperate Maritime (-5°C Design, UK/IE/NZ) |
| Building Insulation Envelope | Older Uninsulated Building (85 W/m² Base) (80.8 W/m² Peak) |
| Peak Space Heating Load | 48.8 kW Thermal |
| Recommended Heat Pump Output (Incl. DHW) | 49.4 kW (168,560 BTU/h · 14.05 Tons) |
| Seasonal Coefficient of Performance (SCOP) | 4.1 (340%–450% Seasonal Efficiency) |
| Annual Heat Demand vs Electricity Consumed | 87,840 kWh Heat → 21,424 kWh Electricity |
Frequently Asked Questions
What kW size heat pump do I need for a 604 m² (6501 sq ft) house?
For a 604 m² (6501 sq ft) building with Older Uninsulated Building (85 W/m² Base) in UK & Temperate Maritime (-5°C Design, UK/IE/NZ), the peak space heating load is 48.8 kW (80.8 W/m²). Including domestic hot water allowance, a 49.4 kW (168,560 BTU/h / 14.05 Ton) heat pump is recommended.
How many kWh of electricity does a 49.4 kW heat pump use per year?
With a Seasonal Coefficient of Performance (SCOP) of 4.1 over 1800 full-load equivalent heating hours, the heat pump consumes approximately 21,424 kWh of electricity per year to deliver 87,840 kWh of heat — saving 66,416 kWh/year compared to direct electric radiators.
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