Solar Savings Calculator
Estimate annual and lifetime savings from solar panels.
Results update as you type.
How it works
Solar panels save money by generating electricity you would otherwise buy from the grid, and this solar savings calculator turns three simple inputs into an estimate of how much you could keep. Enter your planned system size, the peak sun hours your location averages, and your electricity rate, and it returns annual energy production, yearly bill savings, and a 25-year lifetime total. The logic is straightforward: a larger array in a sunnier location produces more kilowatt-hours, and every kilowatt-hour you generate offsets one you no longer purchase. The higher your electricity rate, the more each generated unit is worth, which is why solar pays back fastest where power is expensive and sunshine is plentiful. Seeing a 25-year figure matters because solar is a long-term investment; panels typically carry warranties around that length, so lifetime savings tell you whether the upfront cost is worthwhile. Homeowners weighing an installation, renters exploring community solar, and students studying renewable economics all use a solar savings calculator to gauge returns before committing. Remember the estimate assumes steady rates and output; real savings shift with rate inflation, panel degradation, and shading, but this gives a clear, defensible baseline for planning.
annual kWh = size × sun hours × 365 · savings = kWh × rate
A solar array's output equals its rated size in kilowatts multiplied by the number of peak sun hours it receives each day, since peak sun hours already fold in intensity. Multiplying by 365 scales that daily energy to a full year of kilowatt-hours. Each of those kilowatt-hours displaces grid power you would otherwise buy, so multiplying annual production by your electricity rate gives the yearly dollar saving, and 25 years reflects a typical panel warranty life.
Source:Standard energy calculation
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter system size, daily peak sun hours and electricity rate.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Annual savings updates instantly as you type — no button to press.
Frequently asked questions
What are peak sun hours and how do I find mine?
Peak sun hours are the equivalent number of hours per day that sunlight hits full strength of 1,000 watts per square metre, bundling a whole day's variable light into one figure. Most of the United States averages between four and six, while sunnier regions reach higher. Solar irradiance maps and installer tools list local values, so enter your area's yearly average for a realistic production estimate here.
Does this calculator account for panel degradation?
No, this estimate assumes constant output across all 25 years for simplicity. In reality panels lose roughly half a percent of capacity per year, so late-life production is somewhat lower than year one. It also assumes your electricity rate stays fixed, whereas rates usually rise over time, which pushes savings up. These two effects partly cancel, so the flat estimate remains a reasonable middle-ground figure for planning.
Why does a higher electricity rate increase savings?
Solar savings come from avoiding grid purchases, so each kilowatt-hour you generate is worth exactly what you would have paid for it. When your rate is high, every self-generated unit displaces a more expensive purchase, making the same array save more money. This is why solar economics look strongest in regions with costly electricity, and why rising utility prices steadily improve the return on an existing installation over its life.
Does this include installation cost or payback time?
No. This tool estimates the savings side only — how much electricity value your panels produce — not the upfront purchase and installation price. To find payback time, divide your net system cost after any incentives by the annual savings shown here. If a system costs $12,000 net and saves about $1,369 a year, payback lands near nine years, after which the remaining savings are effectively free energy.
Will I really produce this exact amount of energy?
Actual output varies with shading, panel orientation, roof tilt, temperature, dust, and inverter efficiency, so treat this as a well-grounded estimate rather than a guarantee. South-facing, unshaded arrays in your stated sun hours come closest. Snow, cloud, and soiling reduce output on given days, while cooler sunny weather can lift it. For a firm figure, a site-specific installer assessment refines these inputs to your exact roof.