Exhaust question?

I want to run an exhaust out of my grow room to outside. Now winter is coming and I dont want too much cold air coming inside of my grow room. Would an inline fan and a hood vent stop cold air from coming inside as long as I have a passive intake somewhere else to decrease negative pressure?
Or simpler form would it let in a lot of cold air when its not running?

i use a 6" dryer vent attached to the outside wall of my house to vent my exhaust. The vent has a flap on it so when the fan is not running the flap closes and does not allow air to come back in the room. I got it at Home Depot.

Mountain Grown said:

i use a 6" dryer vent attached to the outside wall of my house to vent my exhaust. The vent has a flap on it so when the fan is not running the flap closes and does not allow air to come back in the room. I got it at Home Depot.

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This is exactly what I wanted to hear. I already was looking at the dryer vents to run my exhaust. Thank you. This is what I will be doing