Residential Solar Energy Savings Calculator
This calculator isolates how many kilowatt-hours a rooftop solar system can generate, what portion of your annual usage it can offset, and how quickly the installation pays back once incentives are applied. Every field ties directly to a specific driver of solar economics—usage, system size, local sunlight, rate, total installed cost, and rebates.
How the calculator quantifies savings
Solar output is simply the system size in kilowatts multiplied by average peak sun hours per day, then scaled to a year. That figure is compared to your annual usage (monthly usage times twelve) to determine the realistic amount of electricity you can replace. Savings multiply that usable production by your electricity rate, and payback divides the net cost after incentives by the annual savings to give you a timeline.
For example, a household that consumes 1,000 kWh per month, installs a 6 kW system in a region with 5 peak sun hours daily, pays $0.16 per kWh, spends $18,000 on the install, and receives $5,000 in rebates will produce 10,950 kWh per year, offset most of its 12,000 kWh load, save about $1,752 annually, and pay back the $13,000 net cost in approximately 7.4 years.
Enter your own solar inputs
Interpreting the results
Solar production that exceeds your annual usage still counts toward savings only up to what you consume unless you are net metering; this calculator caps the offset at your usage so you can measure how much of your utility bill you actually eliminate. A short payback period (ideally under ten years) means the system finances itself quickly and begins delivering pure electricity savings.
- Match system size to your roof space and typical usage to avoid oversizing.
- Factor in local sun hours—cloudier climates produce fewer kWh per kW of panels.
- Incentives dramatically reduce the upfront cost and shorten payback, so include federal, state, and utility rebates.
- Higher utility rates benefit you because every kWh generated replaces more expensive grid power.