Understand cubic feet per minute, blower airflow and why correct air volume is essential for heating, cooling, humidity control and equipment reliability.
CFM stands for cubic feet per minute and describes the volume of air moving through the system.
Forced-air HVAC equipment depends on sufficient airflow to transfer heat between the equipment and the occupied space. Too little or too much airflow can affect capacity, temperatures and humidity control.
Actual airflow depends on blower performance and the resistance imposed by filters, coils, ducts, fittings and registers.
Volume of air moved per minute.
Shows how blower airflow changes as external static pressure changes.
Must support evaporator heat transfer and latent/sensible performance.
Must remove heat from a furnace or deliver heat-pump output appropriately.
Distribution depends on branch-duct capacity and balancing.
Supply air cannot circulate properly without a return path.
Many service symptoms are easier to understand when you know what the system is trying to do. Pressure, temperature, airflow, heat transfer and controls are connected; a change in one can affect several measurements elsewhere in the system.
Professional HVAC diagnosis may require electrical meters, refrigeration gauges and temperature probes, airflow or static-pressure instruments, combustion analyzers and manufacturer-specific procedures. The Academy explains the concepts without encouraging unsafe internal testing.
Connect pressure, temperature and phase change.
Understand the air side of the system.
Review the complete system in homeowner terms.
Look up unfamiliar HVAC terminology.
Use the Learning Center for homeowner-focused explanations, the Troubleshooting Center for symptoms, and the Buying Guides when you are evaluating equipment or proposals.
Connect the technical concept to the complete residential system.
Look up related components, measurements and trade terminology.