Heat Pump Sizing for 42 m² (452 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 Pump1.8 kW6,142 BTU/h (0.51 Tons)
Annual Electricity Usage367 kWh/yrDelivers 1,652 kWh Heat (SCOP 4.5)
Savings vs Direct Electric1,285 kWh/yrSpecific Load: 28.0 W/m²
Electrical Circuit (230V)6 A BreakerPeak Compressor Input: 0.49 kW
Thermal & Electrical Specification Table (42 m² / 452 sq ft)
| Heated Floor Area | 42 m² (452 sq ft) |
| Climate Zone & Design Outdoor Temp | Australia & Mild APAC (Sydney/Melbourne/Tokyo) |
| Building Insulation Envelope | Modern / New Build Insulation (35 W/m² Base) (28.0 W/m² Peak) |
| Peak Space Heating Load | 1.18 kW Thermal |
| Recommended Heat Pump Output (Incl. DHW) | 1.8 kW (6,142 BTU/h · 0.51 Tons) |
| Seasonal Coefficient of Performance (SCOP) | 4.5 (340%–450% Seasonal Efficiency) |
| Annual Heat Demand vs Electricity Consumed | 1,652 kWh Heat → 367 kWh Electricity |
Frequently Asked Questions
What kW size heat pump do I need for a 42 m² (452 sq ft) house?
For a 42 m² (452 sq ft) building with Modern / New Build Insulation (35 W/m² Base) in Australia & Mild APAC (Sydney/Melbourne/Tokyo), the peak space heating load is 1.18 kW (28.0 W/m²). Including domestic hot water allowance, a 1.8 kW (6,142 BTU/h / 0.51 Ton) heat pump is recommended.
How many kWh of electricity does a 1.8 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 367 kWh of electricity per year to deliver 1,652 kWh of heat — saving 1,285 kWh/year compared to direct electric radiators.
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