air in and out

[dfkeddy]

what would be the best sizes for the fresh air intake and exhaust?

 

[umbra]

it depends on the size of space

 

[ArtVandolay]

As is generally the case, bigger is better, everything else being equal. :hubba:

 

[pcduck]

I try to have the exhaust just a little bit bigger than the intake. This ensures that all the air is being removed from the room and not wafting back out the door when I enter. I think it is called negative air pressure when this happens.

 

[The Hemp Goddess]

I like to exchange the air in my room 3-4 times a minute. I also have larger exhaust fans than intake fans. If you have a small space, you may be able to use a passive intake.