Airflow Planning Tool
Duct / CFM / Airflow Calculator
Use this when weak airflow, one hot room, duct changes, filter restrictions, or replacement sizing are part of the conversation.
Last updated June 5, 2026Reviewed by Climate Control Services team
Quick answer
How much airflow does my AC need?
A common planning target is about 350 to 450 CFM per ton, with 400 CFM per ton used as a typical cooling midpoint. Real airflow depends on ducts, static pressure, filters, blower setup, coil condition, and room balance.
How This Calculator Works
Target airflow = system tonnage x selected CFM per ton. Room share estimate = total airflow x room square footage divided by conditioned square footage.
Florida Factors to Review
In humid Florida homes, airflow that is too low can reduce comfort, while airflow that is too high can affect humidity removal. Duct condition and return air matter as much as equipment size.
Calculator FAQs
Is 400 CFM per ton always correct?
No. It is a common planning midpoint. System design, humidity goals, equipment, ducts, filters, and static pressure can change the target.
What causes weak airflow from vents?
Common causes include dirty filters, blocked returns, duct restrictions, blower issues, coil problems, duct leakage, closed dampers, or installation and balancing issues.
Can duct problems make a new AC perform poorly?
Yes. If ducts and returns cannot move the required air, a new system may still leave rooms hot, humid, noisy, or uneven.
Estimate Disclaimer
Calculator results are planning estimates for homeowner education. They are not a Manual J load calculation, diagnostic finding, utility bill audit, financing approval, rebate confirmation, or installed-price quote. Climate Control Services can inspect the home, review equipment, and explain written options before work begins.