Heat Pump Sizing for 300 m² (3,229 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 Pump21.0 kW71,655 BTU/h (5.97 Tons)
Annual Electricity Usage6,347 kWh/yrDelivers 28,560 kWh Heat (SCOP 4.5)
Savings vs Direct Electric22,213 kWh/yrSpecific Load: 68.0 W/m²
Electrical Circuit (230V)32 A BreakerPeak Compressor Input: 5.68 kW
Thermal & Electrical Specification Table (300 m² / 3,229 sq ft)
| Heated Floor Area | 300 m² (3,229 sq ft) |
| Climate Zone & Design Outdoor Temp | Australia & Mild APAC (Sydney/Melbourne/Tokyo) |
| Building Insulation Envelope | Older Uninsulated Building (85 W/m² Base) (68.0 W/m² Peak) |
| Peak Space Heating Load | 20.4 kW Thermal |
| Recommended Heat Pump Output (Incl. DHW) | 21.0 kW (71,655 BTU/h · 5.97 Tons) |
| Seasonal Coefficient of Performance (SCOP) | 4.5 (340%–450% Seasonal Efficiency) |
| Annual Heat Demand vs Electricity Consumed | 28,560 kWh Heat → 6,347 kWh Electricity |
Frequently Asked Questions
What kW size heat pump do I need for a 300 m² (3229 sq ft) house?
For a 300 m² (3229 sq ft) building with Older Uninsulated Building (85 W/m² Base) in Australia & Mild APAC (Sydney/Melbourne/Tokyo), the peak space heating load is 20.4 kW (68.0 W/m²). Including domestic hot water allowance, a 21.0 kW (71,655 BTU/h / 5.97 Ton) heat pump is recommended.
How many kWh of electricity does a 21.0 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 6,347 kWh of electricity per year to deliver 28,560 kWh of heat — saving 22,213 kWh/year compared to direct electric radiators.
Compare Other Home Sizes & Climate Zones
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