Why Does the Cfm Per Ton of Air Conditioning Vary?

The cubic foot per minute, or cfm, per ton of air conditioning varies depending on application. Approximately 400 cfm is required for normal use, while 500 cfm is needed for high sensible heat situations. High latent heat loads use 350 cfm. Sensible heat directly affects the temperature of the room, while latent heat does not affect temperature because it causes a change in state.

An air conditioner's cfm rating describes the volume of air, in cubic feet, that flows through the unit in one minute. A/C units in high sensible heat environments run at higher cfm values because of the increased cooling load. With normal cooling loads, the A/C unit requires approximately 7.5 air changes per hour to maintain a comfortable environment.