For the last 30yrs or so here at our faciility they have used differential air flow switches to prove air flow/fan running. As i am going through and replacing the old equipment,sensors and controls to our new Tridium/bacnet network I am wondering if sticking with the differential air flow switches are worth sticking with. I have never used the CT's for fan proof before and would just like your opinions on whether or not it is worth it to use them over the differential switches.

At the same time i would probably throw one on the compressor at the same time and trend them both for energy usage.