Exhaust fan question

hey there!
I have one question, does the exhaust fan need to work all the time? Or i can use it with digital thermostat, and turn off/on only when temperature is not ok?

You can use a digital thermometer to regulate your fan. But, if you have your exhaust fan hooked up to a carbon filter, you will most likely want to keep it on all the time during flowering to keep the smell away.

besides temp control, the plants need fresh air as well so if the fan is only running a few minutes every day, it could slow growth. I ran into that problem in a barn in winter a few yrs ago. in subzoero weather,the light kept the room at 70 so the fan never kicked on. a small vent at the top helped. heat rises so it drew in some air from the passive intake.

ok, how strong lamp did you had, and what size was your room? i will have passive intake also.

Since photosynthesis doesn't stop and the plants don't stop putting out waste O2 I keep my exhaust on most of the time.

400 watt hps & 16 4 foot t8 floros in an insulated box 4x4x7 feet. it was sealed till I added the vent and was using 5 gallon buckets w/ soil. work kept me away for up to a week at a time so I rigged a timer & drip watering system up. i noticed slow growth after a few weeks of not checking often compared to growth when I could check daily. guessed it was air & added a vent.-it seemed to help.