Public-benefit foundation · UIC 208908769 · Sofia Transparency

Terms of use

Our material is free to read, quote and reuse with attribution. It is general research, not advice about your specific situation.

Last updated 12 August 2026

Who publishes this site

Foundation "Institute for Sustainable Development and Innovation", a Bulgarian public-benefit foundation, ЕИК/UIC 208908769. See our transparency page to verify us in the public register.

Using our material

Unless a page says otherwise, the research, guides, checklists and methods we publish may be read, quoted, translated and redistributed freely, including inside a commercial organisation, provided you credit the Institute and link to the original page where practical. You may not present our material as your own work, or use our name to imply that we endorse a product, service or organisation.

Our name, logo and visual identity are not covered by that permission and remain ours.

What our material is, and is not

Everything here is general research published in the public interest. It is not engineering advice, legal advice, financial advice or a professional opinion about your circumstances, and no relationship of professional advice arises from reading it.

Decisions about industrial systems, energy investments and regulatory compliance depend on specifics we cannot see. Our figures are ranges built on stated assumptions; if those assumptions do not hold in your case, the conclusion may not either. That is why we publish the assumptions. Please have material decisions checked by someone who can examine your actual installation, data or legal position.

On our free tools. They give a first-pass, indicative result from the limited information you enter. A tool result is not a compliance assessment, an engineering study or a quotation, and each tool states its own limits on the page.

Accuracy, and reporting an error

We take accuracy seriously and we still expect to be wrong sometimes. If you find an error, tell us and show your working: info@isdifoundation.com. We correct errors in place and record what changed and when, rather than quietly amending the text.

To the extent permitted by law, we accept no liability for loss arising from reliance on material published here. Nothing in these terms limits liability that cannot lawfully be limited.

Links to other sites

We link to external sources so you can check our work. We do not control them and linking is not endorsement. We carry no advertising and no affiliate links: if we link to a product or supplier, it is because it is relevant evidence, and we receive nothing for it.

Availability

We aim to keep the site available and its material current, but we do not guarantee uninterrupted access, and we may add, revise or withdraw material at any time. Where we withdraw something because we no longer stand behind it, we say so.

Governing law

These terms are governed by Bulgarian law, and disputes fall to the competent courts of the Republic of Bulgaria. This does not remove any protection you have under the mandatory consumer law of your country of residence.