Heat Pump Sizing for 66 m² (710 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 Pump5.1 kW17,402 BTU/h (1.45 Tons)
Annual Electricity Usage1,397 kWh/yrDelivers 6,286 kWh Heat (SCOP 4.5)
Savings vs Direct Electric4,889 kWh/yrSpecific Load: 68.0 W/m²
Electrical Circuit (230V)10 A BreakerPeak Compressor Input: 1.38 kW
Thermal & Electrical Specification Table (66 m² / 710 sq ft)
| Heated Floor Area | 66 m² (710 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 | 4.49 kW Thermal |
| Recommended Heat Pump Output (Incl. DHW) | 5.1 kW (17,402 BTU/h · 1.45 Tons) |
| Seasonal Coefficient of Performance (SCOP) | 4.5 (340%–450% Seasonal Efficiency) |
| Annual Heat Demand vs Electricity Consumed | 6,286 kWh Heat → 1,397 kWh Electricity |
Frequently Asked Questions
What kW size heat pump do I need for a 66 m² (710 sq ft) house?
For a 66 m² (710 sq ft) building with Older Uninsulated Building (85 W/m² Base) in Australia & Mild APAC (Sydney/Melbourne/Tokyo), the peak space heating load is 4.49 kW (68.0 W/m²). Including domestic hot water allowance, a 5.1 kW (17,402 BTU/h / 1.45 Ton) heat pump is recommended.
How many kWh of electricity does a 5.1 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 1,397 kWh of electricity per year to deliver 6,286 kWh of heat — saving 4,889 kWh/year compared to direct electric radiators.
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