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Solar PV Sizing Calculator

AS/NZS 4777.2:2020 & AS/NZS 5033:2021 (Australian Conditions)

◆ Phase 3 Calculator

Inputs

Typical AU household: 15–25 kWh/day

Australia: 3.5–6.0 h/day (latitude dependent)

0° = North (optimal), 90° = East, 180° = South, 270° = West

Optimal ≈ latitude (e.g., 35° for Melbourne)

▶Advanced parameters

Typical modern: 370–440W

Soiling, cabling, temperature, inverter (typical: 12–18%)

Modern inverters: 95–98%

0 = no limit, 5 kW = single-phase typical, 10 kW = three-phase

Results

System Size

5.6

kW

14 panels @ 400W

❌

Export limit compliance

5.7 kW (<= 5)

✅

Inverter oversizing ratio

1.07 ratio (<= 1.33)

✅

Roof area adequacy

40 m² (>= 23.8)

❌

DC string voltage range

67 V (<= 600)

Number of Panels14
Inverter Size6 kVA
Daily Yield20.8 kWh/day
Annual Yield7,594 kWh/year
Specific Yield1356 kWh/kWp/year
Self-Consumption96.1%
Roof Area Required23.8 m²
Simple Payback3.8 years

Inverter size (6 kVA) exceeds export limit (5 kW). May require additional export control hardware.

Important: These results are indicative only. Solar PV systems must be designed and installed by a certified installer in accordance with AS/NZS 4777.2:2020 and AS/NZS 5033:2021. Obtain professional quotes and verify tariff assumptions independently.

Solar PV System Design Guide — AS/NZS 4777.2:2020 & AS/NZS 5033:2021

Grid-connected solar PV systems convert sunlight to electricity for on-site consumption and grid export. This calculator determines the optimal system size, panel count, inverter capacity, and energy yield based on site conditions and load profile.

System Sizing Components

  • Daily energy consumption (kWh): Sum of all on-site electrical loads to be offset by solar generation
  • Peak sun hours (PSH): Location-specific metric; Australia typically 3.5–6.0 hours/day depending on latitude and season
  • Roof area and orientation: North-facing optimal in southern hemisphere (0°); east (90°) and west (270°) reduce output
  • Roof tilt: Optimal angle approximately equals latitude (e.g., 35° for Melbourne)
  • System losses: Account for soiling (2–3%), cabling (2–3%), temperature (5–7%), and inverter efficiency (4–5%)

Key Compliance Requirements

  • Export limiting: Single-phase systems typically limited to 5 kW, three-phase to 10 kW per AS/NZS 4777.2 Clause 4.2
  • Inverter sizing: Maximum 1.33 × DC array size (safety margin per AS/NZS 4777.2 Clause 4.2)
  • DC string voltage: Typically 200–600V for residential systems (AS/NZS 5033 Clause 4.2)
  • Anti-islanding: All grid-connected inverters must have automatic disconnection on grid failure

Performance Metrics

  • Specific yield: Annual energy per kW of installed capacity; Australia typically 1000–1400 kWh/kWp/year
  • Self-consumption: Percentage of generation used on-site (vs. exported); higher = better ROI without batteries
  • Payback period: Simplified estimate assuming typical Australian tariffs (~$0.30/kWh consumption, ~$0.05/kWh feed-in)

Disclaimer: These results are indicative only. Solar PV systems must be designed and installed by a certified solar installer in accordance with AS/NZS 4777.2:2020 and AS/NZS 5033:2021. Tariff rates, installation costs, and site conditions vary significantly. Obtain professional quotes and independent verification before purchasing.