Intake fan for small room - what size for passive exhaust vent?

I have an exhaust fan & intake vent already for my main room, but I'm creating a small veg room within the room (using panda film). I will be using a small intake duct booster fan and I was wondering if the passive exhaust vent should be twice the area of the fan, just as is for passive intake vents when exhaust fans are present.

I've had someone say that it should be the same size and another person say it should be the same as a passive intake vent, in that it should be twice the area of the fan diameter; so I'm trying to get some more opinions/facts on the topic.

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You would follow the same guideline for the passive exhaust as if it were a passive intake. Just be careful when using any kind of intake fan . If the room where the exhaust fan resides is not properly sealed you could create some positive pressure, although in your particular case I doubt that would happen.

ok. Basically I have a 11x10x10 room and I'm sectioning off a 7x3x10 area just for mothers & clones, so most of the grow the only plant that will be in the mini-veg room is 1 or 2 small bonsai mother plants. The mini-veg room will be exhausting into the main room. I also figure since the mini veg room will only have 1 or 2 small plants, a lot of the c02 won't be used which could benefit the main room assuming pressure's fine.

I'm assuming that this mini veg room will not create too much heat that would adversely affect the flowering room. Come to think if it , sometimes you want a little heat in the flowering room depending on the time of year. During winter I do the passive exhaust that you're planning.

A set of dampers in the veg room (although my veg room isn't small rather it is 2400 watts) opens up topside so that cold air will pass through the ceiling past the lamps and then ducted straight into the flowering room. A thermostat will also let those topside dampers close when spring rolls in and open the floor vent dampers instead then the veg room goes back to bottom to top raised floor ventilation, exhausted on its own pair of 10" can fan/filter combos (with homemade 8' silencers straight through the ceiling vented out from the basement past the first floor and out the second floor vents).

I figure this way the flowering room can get raised floor "bottom to top" ventilation year round . By doing it this way I simply don't get to ventilate from bottom to top in the veg room during winter. If you're room is in a basement you could get some free heat (and a little free co2) from a natural gas boiler room if it is situated in such a way where the veg room would take in air from it passively. That's even if you need it.

For all I know you're somewhere that winter never gets too cold. Although, it's worth mentioning to never re-route a boiler or furnace flue pipe. Even though a certain amount of carbon monoxide can be converted to co2 through ambient humidity, most of it could end up leaking into the surrounding environs of resident humans... Sorry for goin' off on a tangent.

Not to go off topic , but what growing method are you gonna use?

I'm in socal so yeah doesn't get too cold and I'm in a warehouse-type environment but it doesn't get too hot. I will be using a vert donut setup. my veg room won't produce much heat if any at all because I'll only have a 250w CFL to keep a bonsai mother going and T5's for clones but t5's won't be on for a majority of the grow anyways.

I was told it's a better idea to use a passive exhaust/fan intake for a small veg room (using panda film) within the flowering room because it makes it easier to get air circulated thru the veg room and into the flowering room. I don't know though, I could just as easily go with a passive intake/exhaust fan.

I mean I guess don't really know why an intake fan/passive exhaust would be better for a mini veg room within the flowering room (flowering room is using a exhaust fan/passive intake).