Pressurized?

I'm going through and setting up everything to finally be done with the building stage and I have an opportunity to somewhat pressurize the grow area. If this is achievable would it be better to have a Positive pressure inside, negative inside, or an equal?

after browsing some o the forums it's believed that a slight negative pressure is better because it helps keeps a steady stream off fresh cool air coming in and stale hot air going out and doesn't let the hot air "sit" for to long.