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

Heat Pump Sizing for 62 m² (667 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 Pump3.8 kW12,966 BTU/h (1.08 Tons)
Annual Electricity Usage1,422 kWh/yrDelivers 5,832 kWh Heat (SCOP 4.1)
Savings vs Direct Electric4,410 kWh/yrSpecific Load: 52.2 W/m²
Electrical Circuit (230V)10 A BreakerPeak Compressor Input: 1.15 kW

Thermal & Electrical Specification Table (62 m² / 667 sq ft)

Heated Floor Area62 m² (667 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 Load3.24 kW Thermal
Recommended Heat Pump Output (Incl. DHW)3.8 kW (12,966 BTU/h · 1.08 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed5,832 kWh Heat → 1,422 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 62 m² (667 sq ft) house?

For a 62 m² (667 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 3.24 kW (52.2 W/m²). Including domestic hot water allowance, a 3.8 kW (12,966 BTU/h / 1.08 Ton) heat pump is recommended.

How many kWh of electricity does a 3.8 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 1,422 kWh of electricity per year to deliver 5,832 kWh of heat — saving 4,410 kWh/year compared to direct electric radiators.