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 â??fresh airâ?� from ?
Inside or outside your home ?
(is their moor co2 in out side or inside air ?
Sins im growing in winter outside air temp are in the 20"s
Do I use outside air ?

If using a active Ventilation sys what do you think of placing one fan in (drill a hole at the top of grow room and use some duct from the ceiling to the floor ) so you get the fresh air to the bottom of you plant`s ! ! ?
and one fan that is sucking air out of your lights in a air cool hood ?
(so you have one side of your air cooled hood light whit a duct and one side whit no duct ?
1 have 1000W on a light rail but I do want to add 2x400W or 2x600W later on
I want to use the heat from the HID`s to heat; my home to help off set the power cost of the grow room
hope you understand this ! !

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).