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

Heat Pump Sizing for 364 m² (3,918 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 Pump30.0 kW102,364 BTU/h (8.53 Tons)
Annual Electricity Usage12,912 kWh/yrDelivers 52,938 kWh Heat (SCOP 4.1)
Savings vs Direct Electric40,026 kWh/yrSpecific Load: 80.8 W/m²
Electrical Circuit (230V)50 A BreakerPeak Compressor Input: 9.09 kW

Thermal & Electrical Specification Table (364 m² / 3,918 sq ft)

Heated Floor Area364 m² (3,918 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 Load29.41 kW Thermal
Recommended Heat Pump Output (Incl. DHW)30.0 kW (102,364 BTU/h · 8.53 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed52,938 kWh Heat → 12,912 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 364 m² (3918 sq ft) house?

For a 364 m² (3918 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 29.41 kW (80.8 W/m²). Including domestic hot water allowance, a 30.0 kW (102,364 BTU/h / 8.53 Ton) heat pump is recommended.

How many kWh of electricity does a 30.0 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 12,912 kWh of electricity per year to deliver 52,938 kWh of heat — saving 40,026 kWh/year compared to direct electric radiators.