Bit more info.
Is the fan used with a carbon filter or on intake fan.
If its a carbon filter fan then you can use it, but your going to want to put it on a timer. say like 15 min's on and 3/4 hour off for veg and 30 min on and 30 off for flower. so that it keep's humidity at a correct level. put in a humidity tester, and monitor it.
If using it for intake then your still going to have to take out the stale hot air but it should be fine to leave on...
Hope this help's.
Dan