Solar Panel Savings Calculator
Estimate your solar savings, payback period, ROI, and environmental impact. Results update instantly.
Last reviewed: June 2026Your Electric Usage
Solar System Details
Financial Settings
Results
How the Calculation Works
Annual kWh Production = System Size (kW) x Peak Sun Hours x 365 x (Efficiency / 100)
Annual Savings = Annual kWh Production x Electricity Rate ($/kWh)
Eligible Credit = System Cost x Credit% when a verified credit applies. The default is 0% for current 2026 residential-solar modeling.
Net Cost = System Cost - Eligible Credit
Payback Period = Net Cost / Year 1 Annual Savings
25-Year Savings compound at the annual electricity rate increase. Net profit = 25-Year Savings - Net Cost.
CO2 Offset uses a fixed 0.386 kg CO2 per kWh assumption for a rough estimate.
How the Solar Panel Savings Calculator Works
This calculator estimates annual solar production, first-year bill savings, simple payback, 25-year savings, return on investment, and a rough CO2 offset. It does not design an array from roof geometry or automatically choose a local incentive package. The main production formula is: annual kWh = system size in kW x peak sun hours per day x 365 x system efficiency.
With the default 6 kW system, 5 peak sun hours per day, and 80% system efficiency, the production estimate is 8760 kWh per year. At the default electricity rate of $0.13/kWh, that is $1138.80 of year-one electricity savings. With the default $18,000 system cost and 0% federal credit, simple payback is 15.8 years. The 25-year savings estimate is $41,519.81 when the annual rate-increase input is 3%.
Federal Credit Field Updated for 2026
The federal credit field is now labeled as an eligible-credit input and defaults to 0%. As of this June 2026 review, the IRS Residential Clean Energy Credit page says qualified property installed through December 31, 2025 may qualify, and that the credit is not available for property placed in service after December 31, 2025. The IRS OBBB FAQ also says installation completed after December 31, 2025 prevents a section 25D claim. If you are modeling an eligible earlier installation, or a separate credit that applies to your case, enter that percentage manually.
What the Calculator Does Not Model
Solar economics depend heavily on location, utility policy, financing, tax liability, roof condition, shading, inverter choice, and net metering or export-credit rules. This page uses a fixed system efficiency input instead of modeling panel degradation, seasonal production, azimuth, tilt, or snow cover. The payback result is a simple first-year-savings payback, not a discounted cash-flow model.
CO2 Offset Assumption
The CO2 result uses a fixed 0.386 kg CO2 per kWh assumption. EPA's eGRID data is the better source for region-specific electricity emissions, because grid intensity varies by state, utility territory, and generation mix. Treat this calculator's CO2 number as a rough national-average-style estimate.
Useful Workflow
Start with your actual installed quote, expected system size, utility rate, and local peak sun-hour estimate. Run one case with no credit, one case with any verified eligible credit, and one case with a lower export value if your utility pays less than retail for excess generation. If payback changes dramatically between cases, the project is probably sensitive to policy and utility assumptions rather than only hardware cost.