Thermometer Trick for Vents

https://www.mediafire.com/file/vb9g5zytt5azzih/pdf-40299-37737.pdf/file

Thermometer Trick for Vents Quick tip from our house: put a cheap kitchen thermometer in a supply vent after the AC runs 15 minutes, then check the air at the return. We see about an 18 degree drop when things are healthy