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

Heat Pump Sizing for 144 m² (1,550 sq ft) — Australia & Mild APAC (Sydney/Melbourne/Tokyo)

Thermal heat loss calculation, recommended heat pump capacity (kW, BTU/h & HVAC Tons), SCOP efficiency, and annual electricity consumption.

Recommended Heat Pump10.4 kW35,486 BTU/h (2.96 Tons)
Annual Electricity Usage3,046 kWh/yrDelivers 13,706 kWh Heat (SCOP 4.5)
Savings vs Direct Electric10,660 kWh/yrSpecific Load: 68.0 W/m²
Electrical Circuit (230V)16 A BreakerPeak Compressor Input: 2.81 kW

Thermal & Electrical Specification Table (144 m² / 1,550 sq ft)

Heated Floor Area144 m² (1,550 sq ft)
Climate Zone & Design Outdoor TempAustralia & Mild APAC (Sydney/Melbourne/Tokyo)
Building Insulation EnvelopeOlder Uninsulated Building (85 W/m² Base) (68.0 W/m² Peak)
Peak Space Heating Load9.79 kW Thermal
Recommended Heat Pump Output (Incl. DHW)10.4 kW (35,486 BTU/h · 2.96 Tons)
Seasonal Coefficient of Performance (SCOP)4.5 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed13,706 kWh Heat → 3,046 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 144 m² (1550 sq ft) house?

For a 144 m² (1550 sq ft) building with Older Uninsulated Building (85 W/m² Base) in Australia & Mild APAC (Sydney/Melbourne/Tokyo), the peak space heating load is 9.79 kW (68.0 W/m²). Including domestic hot water allowance, a 10.4 kW (35,486 BTU/h / 2.96 Ton) heat pump is recommended.

How many kWh of electricity does a 10.4 kW heat pump use per year?

With a Seasonal Coefficient of Performance (SCOP) of 4.5 over 1400 full-load equivalent heating hours, the heat pump consumes approximately 3,046 kWh of electricity per year to deliver 13,706 kWh of heat — saving 10,660 kWh/year compared to direct electric radiators.