What size solar system do I need in Australia?

A typical Australian home uses 15–25 kWh/day and needs a 6.6 kW solar system. Larger homes or homes with pool pumps and EVs may need 10–13.3 kW. The calculator uses your quarterly bill and city-specific peak sun hours (Darwin: 5.6, Sydney: 4.5, Melbourne: 4.1, Brisbane: 5.0, Adelaide: 5.0, Perth: 5.5) to recommend the right size.

How much does solar save on electricity bills in Australia?

A 6.6 kW system in Sydney generates about 26 kWh/day (9,500 kWh/year). At 30c/kWh for self-consumed power and 10c/kWh feed-in tariff, total annual benefit is typically $1,500–$2,500 depending on self-consumption rate. Payback periods range from 3–6 years for well-sized systems in 2026.

What is the STC rebate for solar in Australia?

Small-scale Technology Certificates (STCs) provide an upfront rebate on solar installations. A 6.6 kW system in zone 3 (Sydney/Melbourne) earns approximately 80–90 STCs. At around $38/STC in 2026, that's roughly $3,000–$3,500 off the installation cost. The number of STCs depends on system size, location (zone 1–4), and years remaining in the scheme (ends 2030).

What is a good solar panel in Australia in 2026?

Top-tier panels for Australian conditions in 2026: Jinko Tiger Neo, LONGi Hi-MO 7, REC Alpha Pure-R, Sunpower Maxeon. For value: Risen, Trina Vertex S+. Look for Tier 1 manufacturers with Australian Clean Energy Council (CEC) approval and at least 25-year product and performance warranty. N-type cells offer better high-temperature performance, important for hot Australian summers.

Solar Calculator Australia

How many solar panels does your Australian home need? Enter your electricity bill and city — get system size, panel count, and estimated payback.

Your electricity details

Quarterly electricity bill?

$AUD

Electricity rate?

$AUD/kWh

Location?

Panel wattage?

Recommended system for Sydney, NSW

11 panels (4.4 kW)

Annual usage6,000 kWh

Annual production6,143 kWh

Peak sun hours4.5 hrs/day

STC rebate est.-$2,200

Net install cost est.$2,640 AUD

Est. annual savings$1,106 AUD/yr

The STC rebate is automatically deducted by your installer at point of sale — you don't need to claim it separately.

Link copied to clipboard

How to Use This Calculator

Enter your quarterly electricity bill

Australian electricity bills are typically quarterly (every 3 months). Enter your average quarterly bill in AUD. If your bills vary seasonally, use an average of the last 4 quarters. Most Australian households pay $300-600 per quarter.

Set your electricity rate

Enter your electricity usage rate in $/kWh. Find this on your bill under "usage charges" or "energy rate." Australian electricity rates vary significantly: South Australia averages ~$0.40/kWh, while Queensland and WA are lower at ~$0.25-0.31/kWh. The calculator divides your bill by this rate to find your quarterly kWh consumption.

Select your city

Your city determines peak sun hours — how many equivalent hours of full-strength sunlight your location receives. Perth and Darwin get the most sun (5.5-5.8 hrs/day), making solar highly productive. Hobart gets the least (~3.8 hrs/day) but solar still makes financial sense due to Tasmania's grid rates.

Choose panel wattage

Select your preferred panel wattage. Australian installers commonly offer 370-460W panels. Higher wattage means fewer panels for the same system size.

The Formula

Annual kWh = (Quarterly bill ÷ Rate) × 4 System kW = (Annual kWh ÷ 365) ÷ (Peak sun hours × 0.85) Panels = System kW × 1,000 ÷ Panel watts Annual production = System kW × Peak sun hours × 0.85 × 365 STC rebate = System kW × Zone multiplier (approx $420–650/kW) Annual savings = Production × 50% × Rate + Production × 50% × FiT

The 0.85 efficiency factor accounts for real-world losses in Australian conditions — heat, dust, inverter efficiency, and wiring losses. The STC (Small-scale Technology Certificate) rebate is Australia's main solar incentive, typically reducing install cost by $400-650/kW depending on your climate zone.

Example

The Smith family — Brisbane, QLD

Average quarterly bill of $380, electricity rate $0.28/kWh, 400W panels.

Quarterly bill$380 AUD

Electricity rate$0.28/kWh

Annual consumption5,429 kWh/yr

Brisbane peak sun hrs5.2 hrs/day

Result

System size needed3.4 kW

Number of panels9 × 400W panels

Annual production5,814 kWh

STC rebate estimate~$2,088

Net install cost~$1,652 AUD

Annual savings~$988 AUD/yr

With a payback period of under 2 years and a 10+ year system life remaining, this is an excellent return for the Smith family. Brisbane's excellent sun resource means small systems go a long way.

FAQ

What is the STC (Small-scale Technology Certificate) rebate in Australia? ▼

STCs are Australia's main solar incentive under the Renewable Energy Target (RET). When you install solar, your system generates a certain number of STCs based on your location (climate zone) and system size. Your installer typically buys these STCs from you upfront and deducts the value from your installation price. In 2026, STCs are worth approximately $38-40 each. A 6.6 kW system in Sydney might generate about 80 STCs worth ~$3,200 in rebate value.

What is a feed-in tariff (FiT) in Australia? ▼

A feed-in tariff is the rate your electricity retailer pays for excess solar energy you export to the grid. In 2026, FiTs range from $0.05-0.20/kWh across Australian states, with the minimum regulated rate varying by state. QLD has a mandated minimum of ~$0.05/kWh; SA can get up to $0.20/kWh from some retailers. To maximize savings, use as much solar during the day as possible (self-consumption) rather than exporting, since the FiT is usually much lower than the rate you pay to import.

What size solar system does the average Australian home need? ▼

The average Australian household uses about 18-20 kWh/day (~6,500-7,300 kWh/year). The most popular system size is 6.6 kW (18 × 370W panels), which is the maximum size eligible for standard single-phase grid connection in most states. This system produces approximately 9,000-11,000 kWh/year depending on location — covering most of a typical home's consumption.

Should I get battery storage with my Australian solar system? ▼

Battery storage is increasingly popular in Australia due to falling FiT rates. If your FiT is only $0.05-0.07/kWh but you pay $0.30+/kWh to import, storing excess solar instead of exporting it dramatically improves savings. Popular options include Tesla Powerwall (13.5 kWh, ~$12,000-14,000 installed) and BYD/Sungrow batteries. State incentives help: VIC's Solar Homes program, SA's Home Battery Scheme, and NT's Home and Business Battery Scheme all offer subsidies.