About AC Sizing Calculator
Last updated: 2026-07-10
What We Do
AC Sizing Calculator is a free online tool that helps you calculate air conditioner size in BTUs based on room size, climate, and insulation. All calculations and lookups run instantly in your browser — no account required, no personal data collected.
Our Mission
We believe HVAC and home information should be accessible to everyone. Government data, regulations, and technical specifications are often buried in hard-to-navigate sources. AC Sizing Calculator consolidates this information into a single, easy-to-use tool that gives you answers in seconds.
How It Works
Enter your details and get results immediately. Our calculations are based on publicly available data from official sources. We regularly review and update our data to ensure accuracy.
Data Sources
Our data comes from authoritative public sources, including:
- ACCA Manual J residential load calculations
- ASHRAE climate zone data
- ENERGY STAR cooling efficiency guidelines
Who Runs This Site
AC Sizing Calculator is part of Niche Tools, an independent project built and maintained by Adam B., a Brooklyn-based developer. Niche Tools builds free, focused reference tools that turn scattered public data — government tables, municipal codes, agency datasets — into answers you can actually use. There is no staff of ghostwriters and no AI-spun filler: each site is built from primary sources, and we cite them.
Editorial Standards
Every data point on this site traces back to a public primary source. When we summarize regulations or statistics, we link the official source so you can verify it yourself. When something is not specified in the source material, we say "not specified" rather than guessing. If you find an error, please report it — corrections ship quickly.
Important Disclaimer
The results provided by AC Sizing Calculator are estimates for informational purposes only. They are not a substitute for professional advice. Always consult a qualified professional before making important decisions based on these results.
Privacy
We take your privacy seriously. AC Sizing Calculator does not collect personal information, require sign-ups, or sell data. Calculator inputs are processed entirely in your browser. Read our full privacy policy for details.
Contact
Have a question, found an error, or want to suggest an improvement? We'd love to hear from you — use the contact form and we'll get back to you.