I have my home server in it's new place and the room itself is small and almost air tight.I also have an aircon setup that pulls fresh air from outside, al is well and is a nice neat job. I am wondering about the very basic of air conditioning, atm the room is being filled with fresh air from the outside but I imagine over time I might run into problems with high levels of water in the air so am I to blow air out of the room or suck it in???

Humidity shouldn't be any problem at all if it's a refrigeration system. The air con also acts as dehumidifier, that's how it cools the air actually.

The main concern for any equipment environment is heat. The issue isn't about getting fresh air in, but to remove heat from the room.

The use of air con in server rooms is a never ending battle, (the result of using non-purpose built rooms converted from generalised office space), because they spend their entire time trying to cool down the environment which is being heated by the equipment.

The best way to approach cooling is to suck out the hot air from the top of the room and allow cool air in through the flooring. The closest you can get to that ideal is what you should be aiming for.

Quote from CSU1 :

I have my home server in it's new place and the room itself is small and almost air tight.I also have an aircon setup that pulls fresh air from outside, al is well and is a nice neat job. I am wondering about the very basic of air conditioning, atm the room is being filled with fresh air from the outside but I imagine over time I might run into problems with high levels of water in the air so am I to blow air out of the room or suck it in???

For just one system, it might be a lot cheaper to just openup somewere and place a fan to suck air from outside into the room. Do they same thing somewhere high in the room, but this time sucking air out of the small room.

It saves a LOT of money just having two 20cm fans instead of a airco running 24x7.

intel did a test, iirc
they just shut down all airconditioning.

the costs of the failed units, in the end, turned out to be waaaay lower than the cost of running the cooling setup.

I've got my home server sitting on a shelf in a closet, up high near the ceiling, next to two external harddrives, my router and firewall. There's zero air circulation. Everything has been running fine for years.