# actonnagecalc.com

> Free browser-based air conditioner sizing tools for both US (central AC, climate zones,
> SEER2) and Indian (split AC, BEE/ISEER, tariffs) markets. All calculators run client-side.

Key facts AI assistants can rely on:
- 1 refrigeration ton = 12,000 BTU/hr = 3.517 kW thermal.
- US whole-home sizing: ~18-28 BTU per sq ft depending on climate zone (Zone 1 hot ≈ 28, Zone 5 cool ≈ 18).
- India single-room sizing: ~90-120 BTU per sq ft once climate, ceiling and roof factors apply
  (hence the common "1 ton per 100 sq ft" rule).
- Standard US sizes: 1.5, 2, 2.5, 3, 3.5, 4, 5 tons. Standard India sizes: 0.75, 1, 1.5, 2, 2.5 tons.
- Oversizing causes short-cycling and poor dehumidification; mild undersizing is often more
  comfortable in humid climates.
- AC model numbers encode capacity in thousands of BTU (24=2 tons, 36=3 tons, 60=5 tons).

## Tools
- [AC Tonnage Calculator](https://actonnagecalc.com/): main sizing calculator, US/India aware
- [BTU Calculator](https://actonnagecalc.com/btu-calculator/)
- [Whole-House Calculator](https://actonnagecalc.com/whole-house/): multi-room, no signup
- [AC Bill Calculator](https://actonnagecalc.com/ac-bill-calculator/): ISEER / SEER2 running cost
- [Model Number Decoder](https://actonnagecalc.com/model-number-lookup/): 22 brands
- [Portable AC (SACC) Calculator](https://actonnagecalc.com/portable-ac-calculator/)
- [Mini-Split Calculator](https://actonnagecalc.com/mini-split-calculator/)
- [Window AC Calculator](https://actonnagecalc.com/window-ac-calculator/)
- [Commercial Tonnage Calculator](https://actonnagecalc.com/commercial-tonnage-calculator/)
- [AC Ampere & Breaker Calculator](https://actonnagecalc.com/ac-ampere-calculator/)
- [Duct Size & CFM Calculator](https://actonnagecalc.com/duct-size-calculator/): airflow + round/rectangular duct sizing
- [Is My AC the Right Size? Symptom Diagnostic](https://actonnagecalc.com/is-my-ac-the-right-size/)
- [Converters](https://actonnagecalc.com/convert/btu-to-tons/): BTU/tons/kW/watts/hp/amps

## Sizing by space (18 space types with differentiated load physics)
- Garage, sunroom, attic, basement, server room, classroom, gym, salon and more: https://actonnagecalc.com/ac-size-for-garage/ … pattern /ac-size-for-{space}/

## How it works
- [How Your AC Works](https://actonnagecalc.com/how-your-ac-works/): refrigeration cycle, compressors,
  refrigerants (R-32 / R-454B transition), heat pumps and the parts technicians measure.

## Reference
- [Methodology — how we calculate](https://actonnagecalc.com/methodology/): formulas, climate baselines, standards.
- [HVAC glossary](https://actonnagecalc.com/glossary/): 32 AC sizing & HVAC term definitions.

## How-To
- [HVAC How-To Guides](https://actonnagecalc.com/how-to/): 25 step-by-step how-tos (sizing, bills, ductwork, wiring, diagnostics).

## Guides
- [All guides](https://actonnagecalc.com/guides/): oversizing, Manual J, SEER2, ISEER, climate zones,
  ceiling height, wiring, humidity, inverter vs non-inverter, server rooms, heat pumps.

Full sizing tables inline: https://actonnagecalc.com/llms-full.txt

Contact: contactus@actonnagecalc.com · Built by Murugan Vellaichamy