Last updated 6 November 2026. A template. Have it reviewed against your own jurisdiction before launch.
1. Agreement
By using payback.solar you accept these terms. If you do not accept them, do not use the site.
2. What the site is
A free educational tool that estimates rooftop solar generation, equipment sizing and payback from public satellite data and the assumptions you supply. It is provided at no charge and funded by advertising.
3. What the site is not — please read this one
The output is an estimate. It is not, and must not be treated as:
- an engineering design or an electrical specification;
- a certification, approval or compliance document for any grid operator or authority;
- a quotation, or any kind of binding price;
- financial, investment or tax advice;
- a guarantee of generation, saving or payback.
Actual performance depends on equipment quality, installation workmanship, shading, maintenance, weather in any given year, tariff structures and regulatory changes — several of which the model cannot see. Always obtain a site survey and a written quotation from a licensed solar installer, and have any electrical work performed and certified by a qualified electrician, before purchasing or installing anything.
4. Accuracy
We work to keep the methodology sound and publish it in full so it can be checked. We make no warranty that results are accurate, complete or fit for any purpose. Irradiance data is supplied by third parties, and long-term averages do not predict any individual year.
5. Limitation of liability
To the fullest extent permitted by law, we are not liable for any loss or damage — including financial loss, loss of savings, equipment damage or lost opportunity — arising from use of this site or reliance on its output. Nothing here excludes liability that cannot lawfully be excluded.
6. Acceptable use
Do not attempt to disrupt the site, scrape it at volume, or use it in any way that breaches the terms of the third-party services it depends on, in particular the usage policies of NASA POWER and OpenStreetMap Nominatim.
7. Intellectual property
Site content and code are ours unless stated otherwise. Solar data is courtesy of NASA POWER. Map data is © OpenStreetMap contributors, available under the Open Database Licence. You may quote our guides with attribution and a link.
8. Third-party links
We link to external resources for reference. We do not control them and are not responsible for their content.
9. Changes
We may revise these terms. The date above shows the current version.
10. Contact
Questions about these terms: see the contact page.