Privacy Policy
The site treats user privacy as a non-negotiable. No account required. No third-party advertising. No sale or sharing of personal data with anyone. Minimal anonymous analytics for site-improvement purposes only. This page documents exactly what data is collected, why, and how to opt out.
What data we collect
| Data type | Collected? | Purpose |
|---|---|---|
| Email address | Only when you email us directly | Reply to your message |
| Name | Only when you provide it | Reply to your message |
| IP address | Logged at server for ~14 days | Security (rate limiting, abuse detection) |
| Country / region | Anonymously aggregated | Understand audience geography |
| Page views | Anonymously aggregated | See which calculators are most useful |
| Referrer URL | Anonymously aggregated | Understand where users come from |
| Browser type, screen size | Anonymously aggregated | Test responsive design coverage |
| Calculator inputs you enter | Not collected — calculations run in your browser | n/a |
| Tracking cookies | Not used | n/a |
| Third-party advertising | Not displayed | n/a |
| Session recording / heatmaps | Not used | n/a |
How we use the data
Anonymous aggregated analytics are used solely to improve the site — to identify which calculators are most heavily used, where load times are slowest, what new pages users would benefit from, and whether changes to the site improve or harm the user experience. We do not build profiles of individual users; we look only at aggregated trends.
If you email us with a question or correction, we use your email address solely to reply to you. We do not add you to any mailing list, do not share your email with third parties, and delete your message after the issue is resolved (or after 12 months, whichever comes first).
Cookies
The site uses no tracking cookies. The site uses one functional cookie to remember a light/dark theme preference if you set one. No advertising or third-party tracking cookies are placed by the site or by any third party we control.
Data sharing and selling
We do not sell, rent, lease, license, trade, or otherwise share personal data with anyone for marketing or commercial purposes. We may share aggregated, anonymised statistics in public reports (e.g. "the site had 100k unique visitors in Q1 2025") but never any data that could identify an individual.
The only exceptions where we may disclose data: (a) legal compliance with a valid court order, (b) protection of the site\'s legal rights against fraud or abuse, (c) emergency situations involving threat to life. In each case we will disclose the minimum data required by law.
Third-party services
The site uses the following third-party services. Each is selected for privacy-respecting practices and configured to minimise data collection:
| Service | Purpose | Data shared |
|---|---|---|
| Hosting provider (CDN edge) | Serve the site over HTTPS | IP address (transient, for routing only) |
| Privacy-respecting analytics (Plausible / Fathom / similar) | Anonymous page-view counts | Country-level geography, page URL, referrer — no IP storage |
| Email provider (transactional) | Forward email contact | Your email address (only when you email us) |
The site does not use Google Analytics, Facebook Pixel, third-party advertising networks, session-recording tools, or any other tracking technology that builds individual user profiles.
Your rights — GDPR, UK GDPR, CCPA, Australian Privacy Act
Depending on your jurisdiction you have the following rights with respect to your personal data:
- Right of access — request a copy of any data we hold about you
- Right to rectification — correct inaccurate data
- Right to erasure ("right to be forgotten") — request deletion of your data
- Right to restrict processing — limit how we use your data
- Right to data portability — receive your data in a machine-readable format
- Right to object — object to processing based on legitimate interest
- Right to withdraw consent — at any time
- Right to lodge a complaint with your data-protection authority (ICO in UK, CNIL in France, EDPB in EU, OAIC in Australia, your state attorney general in the US)
To exercise any of these rights, contact us via the address in the site footer. We respond within 30 days.
Children
The site is intended for adults engaged in engineering, electrical, structural, and HVAC work. We do not knowingly collect personal data from children under 13 (under 16 in the EU). If you become aware that a child has provided us with personal data, contact us immediately and we will delete the data.
Changes to this policy
We may update this privacy policy from time to time to reflect changes in our practices, the services we use, or applicable law. Material changes will be flagged at the top of this page for 30 days. The current version is identified by the "Last updated" date below.
Contact
For privacy questions, data-subject requests, or to report a privacy concern, contact us at the email address listed in the site colophon. Include "Privacy" in the subject line for fastest response.
Last updated: 2025-04-30.