Thermometer Trick for Vents

https://violetmetric.com/s/ILRo5TG_pCXZ_1LQZ-gWj

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