Solar Panel Savings Calculator
Estimate your annual solar savings, payback period, and 25-year return on a home solar installation. Country-specific electricity rates, incentives, and solar generation data included.
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How to use this calculator
- 1
Select your country to load local electricity rates, install costs, and solar generation data.
- 2
Enter your average monthly electricity bill to estimate your current consumption.
- 3
Enter your available roof area in square metres for the system size to be auto-calculated.
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Optionally override the system size in kW if you already have a quote.
- 5
Review the annual savings, payback period, and 25-year return on your solar investment.
Frequently asked questions
How accurate is the payback period estimate?
The payback period shown is a ballpark estimate based on average electricity rates, typical solar generation for your country, and representative installation costs. Actual figures vary by installer, roof orientation (south-facing is ideal in the northern hemisphere), shading, and local incentive availability. Get 2–3 quotes from certified installers for accurate numbers.
What is the US Federal Investment Tax Credit (ITC)?
The US federal ITC allows homeowners to deduct 30% of solar installation costs from their federal income taxes. As of 2024, the ITC is 30% and is scheduled to remain at this level through 2032 under the Inflation Reduction Act. You must have sufficient tax liability to use the full credit (unused credit can be carried forward).
What is the Smart Export Guarantee in the UK?
The Smart Export Guarantee (SEG) requires licensed electricity suppliers to pay homeowners for excess solar electricity they export to the grid. Rates are set by each supplier (not the government) and typically range from 1p to 15p/kWh. Octopus Energy and others offer competitive SEG rates.
How does Australia's solar rebate work?
Australia's Small-scale Renewable Energy Scheme (SRES) provides Small-scale Technology Certificates (STCs) for solar installations. Most installers deduct the STC value directly from the quoted price, effectively giving you an upfront discount. This is why Australian solar installation costs are among the lowest in the developed world (around A$1–1.50/W).
What is India's rooftop solar subsidy?
The Indian central government provides a subsidy of 30% on the benchmark cost for residential rooftop solar systems up to 3kW, and 15% for systems from 3–10kW. State-level subsidies may also apply. The PM Surya Ghar: Muft Bijli Yojana scheme (2024) extended subsidies further. Check your state's DISCOM for current rates.
Solar Panel Savings Calculator — Estimate Payback Period and 25-Year ROI
Is Solar Worth It in Your Country?
The economics of solar vary dramatically by country. Australia has the world's highest residential solar uptake — heavily subsidised install costs (A$1–1.50/W) combined with high electricity rates (A$0.32/kWh) create payback periods as short as 3–5 years. The US federal 30% tax credit under the IRA makes a 5kW system in a sun-rich state like Arizona or Texas pay back in 6–8 years. The UK's lower sun hours (950 kWh/kW/year vs Australia's 1,600) extend payback but the Smart Export Guarantee provides ongoing income.
How Solar Panels Generate Savings
Every kilowatt-hour your solar panels generate replaces electricity you would otherwise buy from the grid. A 5kW system in the US generates around 7,500 kWh/year — saving approximately $1,200/year at $0.16/kWh. In Australia the same system generates 8,000 kWh and saves A$2,560/year at A$0.32/kWh. Any excess generation exported to the grid earns a feed-in tariff (UK SEG, AU feed-in rate) — a secondary income stream on top of your bill savings.
The 25-Year Case for Solar
Modern solar panels carry 25-year performance warranties and typically degrade at less than 0.5% per year. Over a 25-year system life, a well-sized installation in a sun-rich location can generate $30,000–$60,000 in electricity savings — against a net install cost of $10,000–$20,000 after incentives. The 25-year return on investment for Australian homeowners often exceeds 300%. Rising electricity prices only improve the economics over time.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →