Air ventilation

Are there any alternatives for good ventilation without sticking a hole in my wall ?

I rent the flat I live in, so not rly in a position to be doing to much work to it. My grow space is about 4 ft by 4 ft with only a few plants growing at the minute, I have a fan blowing in there which keeps the temp down and also helps circulate the air, but it obviously doesnt do a lot to bring fresh air in to the 'garden'. There's a large window in the room (goes from floor to ceiling,) that brings a lot of fresh air in, but im not sure if this is sufficient.

My plants are healthy enough so maybe they are fine as they are, but im always looking to improve my set up.

Cheers in advance

 

Get another fan to direct air from window to growspace,they can always use more fresh air indoors .Unless you are blowing the plants over there is no negitive effects to utilizing multiple fans for fresh air and to keep temps down when a intake and exhaust cannot be properly installed.You can always have a oscillating up high in the grow area removing the stale/warm air and another low bringing in the cool/fresh air.Peace

 

Cheers meangreen