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

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 Pump32.1 kW109,530 BTU/h (9.13 Tons)
Annual Electricity Usage13,842 kWh/yrDelivers 56,754 kWh Heat (SCOP 4.1)
Savings vs Direct Electric42,912 kWh/yrSpecific Load: 52.2 W/m²
Electrical Circuit (230V)60 A BreakerPeak Compressor Input: 9.73 kW

Thermal & Electrical Specification Table (604 m² / 6,501 sq ft)

Heated Floor Area604 m² (6,501 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 Load31.53 kW Thermal
Recommended Heat Pump Output (Incl. DHW)32.1 kW (109,530 BTU/h · 9.13 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed56,754 kWh Heat → 13,842 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 Standard Double-Glazed Insulation (55 W/m² Base) in UK & Temperate Maritime (-5°C Design, UK/IE/NZ), the peak space heating load is 31.53 kW (52.2 W/m²). Including domestic hot water allowance, a 32.1 kW (109,530 BTU/h / 9.13 Ton) heat pump is recommended.

How many kWh of electricity does a 32.1 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 13,842 kWh of electricity per year to deliver 56,754 kWh of heat — saving 42,912 kWh/year compared to direct electric radiators.