Bring the air from inside your home- humans breathing releases CO2 so the bonus is extra CO2, as well as correct temps and less risk of pests.

REturn the exhaust to inside your home in winter but you may have to use a carbon filter to prevent the house from stinking weed.

The way you explained your air cooled hood works fine. If I understand you correctly it is the same way I run mine:
Hood
Duct sucking out
Fan sucking from duct into the room I want to heat

Heating your house with extra growroom heat works! Don't forget the ballasts are very warm too (electronic ballasts are cooler).
stinkyattic Reviewed by stinkyattic on . Ventilation system I grow in the winter and DO NOT USE AC or co2 I have raid FAQ`s on Ventilation setup`s # 1 Ventiliation Explained - Part 1 | BGHydro # 2 Ventilation Part II -- Choosing An Inline Fan # 3 Ventilation Part III -- Installing an Exhaust Fan but the FAQ DO NOT discuss some item`s that I am having problems whit they do not discuss where you get the ā??fresh airā? from ? Inside or outside your home ? Rating: 5