Disclaimer

Last updated: April 30, 2026

1. Estimate Nature

All calculator results on GainTally are estimates based on user-provided inputs combined with public data from the National Renewable Energy Laboratory (NREL) and the U.S. Energy Information Administration (EIA). Actual values may differ significantly based on individual circumstances, equipment quality, installation factors, weather variations, and policy changes.

2. Accuracy Range

  • Solar production: ±10% (PVWatts benchmark)
  • Energy savings: ±15% (DOE/ENERGY STAR benchmarks)
  • EV cost calculations: ±5% (DOE Vehicle Cost Calculator)

These ranges represent typical accuracy under normal conditions; outliers exist.

3. Professional Consultation

Investment decisions over $5,000 should always involve consultation with licensed professionals:

  • Solar: NABCEP-certified installer
  • EV: dealer or fleet manager
  • Energy efficiency: BPI/RESNET-certified auditor
  • Financial planning: CFP or fiduciary financial advisor

4. Data Freshness

  • NREL PVWatts data updates annually.
  • EIA electricity rates update quarterly.
  • EIA gas rates update quarterly.
  • Federal/state incentive data is refreshed manually upon policy changes; GainTally cannot guarantee real-time accuracy.

5. Third-Party Data Attribution

Solar irradiance data: National Renewable Energy Laboratory (NREL), U.S. Department of Energy. We credit DOE/NREL/ALLIANCE for solar resource data used throughout this site. PVWatts® is a registered trademark of the Alliance for Sustainable Energy, LLC, operating NREL under contract with DOE.

Electricity and gas rates: U.S. Energy Information Administration (EIA), data publicly released.

ENERGY STAR® and federal tax credit information from EnergyStar.gov and IRS publications.

6. No Warranty

GainTally is provided “AS IS” without warranties of any kind, express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, or non-infringement. GainTally does not warrant that calculator results will be uninterrupted, error-free, or free from omissions.

7. Related Policies

For our complete privacy practices, see our Privacy Policy. For terms of use, see our Terms of Service.

8. FTC Affiliate Disclosure

GainTally participates in affiliate marketing programs, which means we may earn commissions on qualifying purchases made through links to partner websites. This relationship does not affect the independence of our calculations or recommendations.

Material Connection

In accordance with the U.S. Federal Trade Commission’s “Guides Concerning the Use of Endorsements and Testimonials in Advertising” (16 CFR Part 255), we disclose any material connections between GainTally and the products or services we mention. When you see a link marked with rel="sponsored" or accompanied by an “As an affiliate, we may earn commission” notice, that link directs to a partner’s website with whom we have a commercial relationship.

Editorial Independence

Our calculator formulas, benchmark ranges, and methodology disclosures are independent of affiliate revenue. NREL PVWatts, EIA, and DOE data sources are used regardless of any commercial partnerships. We do not modify recommendations based on affiliate payouts.

Current Affiliate Partners

At the time of writing, GainTally may include affiliate links to third-party platforms such as solar quote services and online retailers. The specific list of partners may change; consult our linked source pages for the most current information.

This disclaimer is provided for informational purposes only and does not constitute legal advice. We recommend consulting a licensed attorney to verify compliance with applicable laws before relying on any calculator estimates for major financial decisions.