About Free HVAC Calculators

Free HVAC Calculators publishes free calculators for heating, cooling, ventilation and air conditioning. They are for homeowners comparing quotes, technicians checking a system, students and anyone who wants to understand the numbers behind HVAC decisions.

What makes these calculators different

Many HVAC calculators give a number without saying where it came from. Ours show the formula, the assumptions and the sources on the same page, and every release is tested against independent calculations. Where a quick tool cannot replace professional work — a Manual J load calculation, a manufacturer’s charging chart, a code requirement — the page says so plainly.

Who runs the site

The site is operated by the FreeHVACCalculators.com team. We are not affiliated with, or endorsed by, ACCA, ASHRAE, ENERGY STAR, AHRI or any manufacturer; we cite their public material as sources.

How the site is funded

The calculators are free. The site may show advertising and clearly labelled sponsored products. Sponsors never influence a calculation, a default value or a recommendation. See the advertising and sponsorship disclosure.

Get in touch

Suggestions, corrections and calculator requests are welcome through the contact page.