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

Heat Pump Sizing for 114 m² (1,227 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 Pump9.8 kW33,439 BTU/h (2.79 Tons)
Annual Electricity Usage4,043 kWh/yrDelivers 16,578 kWh Heat (SCOP 4.1)
Savings vs Direct Electric12,535 kWh/yrSpecific Load: 80.8 W/m²
Electrical Circuit (230V)20 A BreakerPeak Compressor Input: 2.97 kW

Thermal & Electrical Specification Table (114 m² / 1,227 sq ft)

Heated Floor Area114 m² (1,227 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 Load9.21 kW Thermal
Recommended Heat Pump Output (Incl. DHW)9.8 kW (33,439 BTU/h · 2.79 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed16,578 kWh Heat → 4,043 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 114 m² (1227 sq ft) house?

For a 114 m² (1227 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 9.21 kW (80.8 W/m²). Including domestic hot water allowance, a 9.8 kW (33,439 BTU/h / 2.79 Ton) heat pump is recommended.

How many kWh of electricity does a 9.8 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 4,043 kWh of electricity per year to deliver 16,578 kWh of heat — saving 12,535 kWh/year compared to direct electric radiators.