Editorial policy and methodology

Research standards

• Facts about prices, incentives and laws come from primary sources where possible: government agencies (IRS, EIA, NREL, DOE, Ofgem, CER, NRCan), legislation and official program pages.
• Market prices use multiple independent reports, and we say which.
• Incentive and legal information carries an "as of" date because it changes often.
• Every guide is reviewed at least twice a year, and immediately when a major rule changes.

Calculator methodology

• Production: system kW × peak sun hours × 365 × 0.78 derate.
• Electricity price: EIA state average residential price, July 2026 release.
• Installed price: $3.00 per watt default, editable.
• Savings: 85% of production valued at your retail rate to reflect lower export credits, rising 3% a year by default, with 0.5% yearly panel degradation.
• Incentives: excluded by default because the US homeowner tax credit ended for systems installed after 2025. Add state or local incentives yourself.

These are planning estimates, not quotes. Your roof, shade, utility tariff and installer will change the result.

Independence

• Writers don't know which companies pay referral fees.
• Advertisers and sponsors cannot review, edit or buy coverage.
• Sponsored content is always labeled.
• We don't accept free products in exchange for coverage.

AI and automation

We use software, including AI tools, to help draft and check content and to run calculations. A person reviews every page before publication and is responsible for its accuracy.

Corrections

Spotted an error? Tell us. We correct factual errors promptly and note significant changes.