Central AC System GuideCentral AC tool
AC Airflow CFM Planner
Estimate the target supply airflow in CFM for a central AC system from its tonnage using the standard cubic-feet-per-minute-per-ton rule of thumb.
Screening result
Fine Print and Sources
Screening estimate only. These tools use only the values you enter and simple planning math. A professional Manual J load calculation is authoritative for equipment sizing, room loads, and final purchase decisions. Confirm with a licensed HVAC pro before you buy.
The 400 CFM per ton figure is a common HVAC rule of thumb for standard cooling, not a value cited to a fetched source. Humid climates often target about 350 CFM per ton to remove more moisture, and dry climates may target about 450 CFM per ton for maximum sensible cooling. Correct airflow depends on duct design, static pressure, and blower capacity, so a professional airflow measurement is authoritative.
- EnergySage central air conditioner sizing guide: explains square-feet-per-ton screening ranges, notes one ton equals 12,000 BTU/h, and warns that oversizing causes short cycling and poor humidity control.
- ENERGY STAR central air conditioning: describes right-sizing and efficiency selection for central AC equipment.