Effective date: July 14, 2026
Disclaimer
Informational tools, not professional advice
The calculators, decoders, charts, and articles on DuctMath are provided for informational and educational purposes. They produce estimates based on standard industry formulas, published reference charts, and manufacturer numbering conventions. They are not a substitute for a professional load calculation (such as ACCA Manual J), manufacturer specifications, an equipment data plate, or the judgment of a licensed HVAC professional.
Verify before you act
Model-number and serial-number conventions vary between manufacturers, product lines, and production years. Rules of thumb — like BTUs per square foot — are starting points, not sizing decisions. Before purchasing equipment, ordering parts, modifying a system, or making warranty claims, verify results against the unit’s rating plate, the manufacturer’s documentation, or the AHRI Directory, and consult a licensed contractor where appropriate.
Refrigerant work
In the United States, handling refrigerant requires EPA Section 608 certification. Tools on this site that involve refrigerant readings (such as superheat and subcooling) are math aids for interpreting measurements taken safely and legally by qualified people — they do not teach or authorize refrigerant handling.
No warranty
This site and its tools are provided “as is” and “as available”, without warranties of any kind, express or implied, including accuracy, completeness, fitness for a particular purpose, or uninterrupted availability. While every calculator is tested before release and corrections are made when errors are reported, we do not guarantee that results are error-free for every input, model, or edge case.
Limitation of liability
To the maximum extent permitted by law, DuctMath and its operators are not liable for any damages arising from the use of, or inability to use, this site — including equipment damage, incorrect purchases, installation decisions, or business losses based on tool results. You are responsible for how you use the information.
Terms of Use
Acceptable use
You may use the tools freely for personal and professional work. You may not scrape the site at abusive volumes, attempt to disrupt it, misrepresent its results as certified engineering documents, or republish its content or code as your own.
Intellectual property
The site’s content, design, and calculator code belong to DuctMath. Manufacturer names (such as Carrier, Trane, Goodman, Lennox, Rheem, and York) are trademarks of their respective owners, used here only to identify numbering conventions — DuctMath is independent and not affiliated with or endorsed by any equipment manufacturer.
Embedding
Contractors and publishers may embed DuctMath calculators on their own sites using the official embed version, where offered, with attribution intact. Contact us through the contact page to request it.
External links
Links to third-party sites are provided for convenience. We are not responsible for their content, accuracy, or policies.
Changes
Tools, content, and these terms may change as the site evolves. Continued use of the site after changes are posted constitutes acceptance of the updated terms.
Contact
Questions about this page: contact@ductmath.com.