Heat Pump Sizing for 404 m² (4,349 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 Pump33.2 kW113,283 BTU/h (9.44 Tons)
Annual Electricity Usage14,330 kWh/yrDelivers 58,752 kWh Heat (SCOP 4.1)
Savings vs Direct Electric44,422 kWh/yrSpecific Load: 80.8 W/m²
Electrical Circuit (230V)60 A BreakerPeak Compressor Input: 10.06 kW
Thermal & Electrical Specification Table (404 m² / 4,349 sq ft)
| Heated Floor Area | 404 m² (4,349 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 | 32.64 kW Thermal |
| Recommended Heat Pump Output (Incl. DHW) | 33.2 kW (113,283 BTU/h · 9.44 Tons) |
| Seasonal Coefficient of Performance (SCOP) | 4.1 (340%–450% Seasonal Efficiency) |
| Annual Heat Demand vs Electricity Consumed | 58,752 kWh Heat → 14,330 kWh Electricity |
Frequently Asked Questions
What kW size heat pump do I need for a 404 m² (4349 sq ft) house?
For a 404 m² (4349 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 32.64 kW (80.8 W/m²). Including domestic hot water allowance, a 33.2 kW (113,283 BTU/h / 9.44 Ton) heat pump is recommended.
How many kWh of electricity does a 33.2 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 14,330 kWh of electricity per year to deliver 58,752 kWh of heat — saving 44,422 kWh/year compared to direct electric radiators.
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