What we do not collect
Watful has no user accounts, no sign-up, no newsletters and no contact forms. We do not ask for, store or sell any personal information. There are no advertising cookies and no cross-site tracking on this site.
Calculator inputs
The numbers you enter into calculators are processed entirely in your browser and are not sent to our servers. The "Share link" button encodes your inputs into a URL — that data leaves your device only if you choose to share the link, and is visible to anyone you share it with.
Local storage
Your light/dark theme preference is saved in your browser's local storage so the site remembers it on your next visit. It never leaves your device and you can clear it at any time through your browser settings.
Analytics
We use Vercel Web Analytics to understand aggregate usage — page views, referrers, country and device type. It is cookieless and does not build visitor profiles: identifiers are anonymous, rotated and never linked to you across sites. See Vercel's analytics privacy documentation for details.
Hosting
The site is hosted by Vercel Inc. Like virtually all web hosts, Vercel processes standard technical request data (such as IP address and browser type) to serve pages, keep the service secure and prevent abuse. Watful does not access or store this data beyond the aggregate analytics described above.
Advertising and affiliate links
Watful currently shows no third-party advertising and contains no affiliate links. If either is added in the future, this policy will be updated first, affiliate links will be clearly labelled, and any advertising that requires consent will ask for it before setting cookies.
External links
Guides and methodology sections link to external resources (for example irradiance databases and manufacturer documentation). Those sites have their own privacy policies that we do not control.
Your rights and contact
Since Watful does not collect or hold personal data about you, there is normally nothing for us to access, correct or delete under the GDPR. If you have any privacy question or believe this page is inaccurate, contact us at privacy@watful.com and we will respond as soon as we can.