Spare Bedroom Growroom - intake?

Ok so im going to set up my spare bedroom that I currently have my grow tents in, into a full grow room after summer when the weather cools down. I already have hole cut in built in wardrobe for exhaust, but am unsure of how to get air intake into room? Through window is not an option. Will crack under door be enough with a couple of oscillating fans in the room?

Lighting will be 2x 1000w + a 600w. Maybe some LED and fluro supplemental.

Wont need air con because will only use this setup during cooler months, just want a way to intake fresh air without cutting holes if possible?

Thanks.

depends on how big is the crack under your door and how wide is your door ,for a 30"door with 1"gap will be ok for 6" fan and possibly a 8" fan if door is a little bigger or gap is for a 10" fan you will want neg pressure so smell does not escape plus you will open door to check on things at least ones or twice a day. the problem will come with the heat I would think not fresh air for the plants

2600w in a bedroom heat will be your problem.