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❄️ Heat Pump & HVAC Thermal Load · EN 12831 & ACCA Manual J Reference

Heat Pump Sizing for 484 m² (5,210 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 Pump39.7 kW135,462 BTU/h (11.29 Tons)
Annual Electricity Usage17,170 kWh/yrDelivers 70,398 kWh Heat (SCOP 4.1)
Savings vs Direct Electric53,228 kWh/yrSpecific Load: 80.8 W/m²
Electrical Circuit (230V)70 A BreakerPeak Compressor Input: 12.03 kW

Thermal & Electrical Specification Table (484 m² / 5,210 sq ft)

Heated Floor Area484 m² (5,210 sq ft)
Climate Zone & Design Outdoor TempUK & Temperate Maritime (-5°C Design, UK/IE/NZ)
Building Insulation EnvelopeOlder Uninsulated Building (85 W/m² Base) (80.8 W/m² Peak)
Peak Space Heating Load39.11 kW Thermal
Recommended Heat Pump Output (Incl. DHW)39.7 kW (135,462 BTU/h · 11.29 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed70,398 kWh Heat → 17,170 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 484 m² (5210 sq ft) house?

For a 484 m² (5210 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 39.11 kW (80.8 W/m²). Including domestic hot water allowance, a 39.7 kW (135,462 BTU/h / 11.29 Ton) heat pump is recommended.

How many kWh of electricity does a 39.7 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 17,170 kWh of electricity per year to deliver 70,398 kWh of heat — saving 53,228 kWh/year compared to direct electric radiators.