i had my defroster on cuz it was raining and i didnt want windows to fog up,and i noticed that white smoke was coming out of my vents ,not the vents by the windsheild but the ones that are used for ac ,heat etc...i figured maybe wator vapor but im not sure ,it only came out few times and when i noticed it came out i think i hear the compressor turn on(makes rpms go up a little) and when it stops it goes away...so whats this white smoke im getting...btw its odorless

 

Yep that's normal. Just the difference in air temperature is causing it.