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

Heat Pump Sizing for 86 m² (926 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 Pump3.5 kW11,942 BTU/h (1.0 Tons)
Annual Electricity Usage1,256 kWh/yrDelivers 5,148 kWh Heat (SCOP 4.1)
Savings vs Direct Electric3,892 kWh/yrSpecific Load: 33.2 W/m²
Electrical Circuit (230V)6 A BreakerPeak Compressor Input: 1.06 kW

Thermal & Electrical Specification Table (86 m² / 926 sq ft)

Heated Floor Area86 m² (926 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 Load2.86 kW Thermal
Recommended Heat Pump Output (Incl. DHW)3.5 kW (11,942 BTU/h · 1.0 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed5,148 kWh Heat → 1,256 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 86 m² (926 sq ft) house?

For a 86 m² (926 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 2.86 kW (33.2 W/m²). Including domestic hot water allowance, a 3.5 kW (11,942 BTU/h / 1.0 Ton) heat pump is recommended.

How many kWh of electricity does a 3.5 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 1,256 kWh of electricity per year to deliver 5,148 kWh of heat — saving 3,892 kWh/year compared to direct electric radiators.