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

Heat Pump Sizing for 316 m² (3,401 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 Pump11.1 kW37,875 BTU/h (3.16 Tons)
Annual Electricity Usage4,605 kWh/yrDelivers 18,882 kWh Heat (SCOP 4.1)
Savings vs Direct Electric14,277 kWh/yrSpecific Load: 33.2 W/m²
Electrical Circuit (230V)20 A BreakerPeak Compressor Input: 3.36 kW

Thermal & Electrical Specification Table (316 m² / 3,401 sq ft)

Heated Floor Area316 m² (3,401 sq ft)
Climate Zone & Design Outdoor TempUK & Temperate Maritime (-5°C Design, UK/IE/NZ)
Building Insulation EnvelopeModern / New Build Insulation (35 W/m² Base) (33.2 W/m² Peak)
Peak Space Heating Load10.49 kW Thermal
Recommended Heat Pump Output (Incl. DHW)11.1 kW (37,875 BTU/h · 3.16 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed18,882 kWh Heat → 4,605 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 316 m² (3401 sq ft) house?

For a 316 m² (3401 sq ft) building with Modern / New Build Insulation (35 W/m² Base) in UK & Temperate Maritime (-5°C Design, UK/IE/NZ), the peak space heating load is 10.49 kW (33.2 W/m²). Including domestic hot water allowance, a 11.1 kW (37,875 BTU/h / 3.16 Ton) heat pump is recommended.

How many kWh of electricity does a 11.1 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 4,605 kWh of electricity per year to deliver 18,882 kWh of heat — saving 14,277 kWh/year compared to direct electric radiators.