Can your static pressure be to low? This discussion came up at work today. You can imagine all of the opinions from people like me that dont really know. I came home at looked at mine, I have the Carrier Infinity control that shows it. My pressure at the moment is 0.05. I have a 4 Ton hp that was on low stage at this reading. The airflow CFM was 500. I dont think I have ever seen it over 0.1. Normally it never runs on a CFM over 1000. I have it set to comfort.