HVAC Sizing Calculator
Rough BTU estimate for heating and cooling load.
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Inputs
Results
- Estimated BTU
- 45,000 BTU
- AC tonnage (approx.)
- 3.8 tons
- Note
- Professional Manual J load calc recommended
Tips
- This is a rough estimate only. Insulation, windows, and orientation affect sizing.
All calculators, planners, and checklists provide estimates for planning purposes only. They are not professional advice. Read full disclaimers
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About HVAC Sizing Calculator
Free online hvac sizing calculator. Rough BTU estimate for heating and cooling load. Instant estimates for your energy & hvac project — no signup required.
Why choose Online Tool Hub?
- Free forever — supported by non-intrusive ads
- Privacy-first — calculations stay in your browser
- Works on desktop and mobile
- Part of 18 free energy & hvac tools on Online Tool Hub
Frequently asked questions
- Is this a professional load calculation?
- No. This is a rough BTU estimate. A Manual J load calculation by an HVAC professional is recommended before purchasing equipment.
- Is my project data sent to a server?
- No. Homeowner calculators run in your browser. Your measurements stay on your device.
- Do I need an account?
- No signup is required. All homeowner tools on Online Tool Hub are free to use.