Solar Payback Calculator

This calculator estimates your annual solar savings and how long the system takes to pay for itself. Annual savings combine the grid electricity you avoid buying with the credit you earn from exporting surplus power:

Annual savings = (self-consumed energy × electricity price) + (exported energy × feed-in tariff)

Payback period = system cost ÷ annual savings

Example: a $10,000 system that saves $1,800 of grid electricity and earns $200 in feed-in credits saves $2,000 per year, giving a payback period of about 5 years. After that point, the energy the system generates is effectively free. The sunlight factor scales generation up or down for your roof orientation, shading and local climate, and the 20-year projection applies a small annual output decline of around 0.5% per year.

For most households, solar is one of the most reliable home investments available. Once the system has paid for itself, every kilowatt-hour it generates either reduces your electricity bill or earns you a feed-in credit. The key drivers of value are how much electricity you use during the day and how much you currently pay per kilowatt-hour.

Use the calculator above to estimate your specific payback period. A shorter payback means a faster return, and anything generated after break-even is essentially free energy.

Several variables shape your return: the upfront system cost, your electricity price, your sunlight conditions and roof orientation, the feed-in tariff offered by your retailer, and how much of your usage happens while the sun is shining. Shifting power-hungry activities such as laundry, dishwashing and charging to daytime hours can meaningfully improve your savings.

Without a battery, surplus daytime energy is exported to the grid for a feed-in credit, and you buy grid power at night. This is the most cost-effective setup for many homes because batteries add a large upfront cost.

With a battery, you store daytime energy to use in the evening, increasing self-consumption and providing backup during outages. Batteries suit households with high evening usage or a strong preference for energy independence, but they lengthen the overall payback period.