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

Heat Pump Sizing for 596 m² (6,415 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 Pump31.7 kW108,165 BTU/h (9.01 Tons)
Annual Electricity Usage13,658 kWh/yrDelivers 55,998 kWh Heat (SCOP 4.1)
Savings vs Direct Electric42,340 kWh/yrSpecific Load: 52.2 W/m²
Electrical Circuit (230V)60 A BreakerPeak Compressor Input: 9.61 kW

Thermal & Electrical Specification Table (596 m² / 6,415 sq ft)

Heated Floor Area596 m² (6,415 sq ft)
Climate Zone & Design Outdoor TempUK & Temperate Maritime (-5°C Design, UK/IE/NZ)
Building Insulation EnvelopeStandard Double-Glazed Insulation (55 W/m² Base) (52.2 W/m² Peak)
Peak Space Heating Load31.11 kW Thermal
Recommended Heat Pump Output (Incl. DHW)31.7 kW (108,165 BTU/h · 9.01 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed55,998 kWh Heat → 13,658 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 596 m² (6415 sq ft) house?

For a 596 m² (6415 sq ft) building with Standard Double-Glazed Insulation (55 W/m² Base) in UK & Temperate Maritime (-5°C Design, UK/IE/NZ), the peak space heating load is 31.11 kW (52.2 W/m²). Including domestic hot water allowance, a 31.7 kW (108,165 BTU/h / 9.01 Ton) heat pump is recommended.

How many kWh of electricity does a 31.7 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 13,658 kWh of electricity per year to deliver 55,998 kWh of heat — saving 42,340 kWh/year compared to direct electric radiators.