About SolarROI Calculator
Independent, mathematical solar financial analysis powered by transparent public datasets.
The residential solar industry is frequently plagued by aggressive sales tactics, opaque pricing models, and wildly exaggerated savings projections. SolarROI Calculator was engineered to provide American homeowners with a completely unbiased, independent, and transparent tool to verify whether solar makes financial sense for their specific home.
Our Primary Data Sources (September 2026 Release)
Unlike generic online calculators that use a single national flat average for electricity rates and sunlight hours, our computation engine relies strictly on primary governmental and scientific sources. Tariffs, irradiance and incentive programmes are held separately per country — a figure sourced for one market is never reused to model another:
1. U.S. Energy Information Administration (EIA)
Residential retail electricity prices (cents/kWh) are sourced from Form EIA-861M (Monthly Update to Annual Electric Power Industry Report). Updated monthly to reflect true delivered energy charges across regulated and deregulated state utility markets.
2. National Renewable Energy Laboratory (NREL)
Solar resource data and daily peak sun hours are modeled from NREL's National Solar Radiation Database (NSRDB) and PVWatts v8 algorithms, factoring in geographic latitude, typical meteorological year (TMY) irradiance, and standard 82% system DC-to-AC conversion derates.
3. Internal Revenue Service (IRS Section 25D)
Federal tax credits are calculated strictly in accordance with 26 U.S. Code § 25D (Residential Clean Energy Credit) as amended by Public Law 117-169 (Inflation Reduction Act).
Engineering & Privacy Commitment
All calculations are executed 100% inside your web browser using client-side JavaScript. We do not require you to create an account, enter a phone number, or submit personal details simply to see an honest financial estimate.