exhaust question

I am in the process of tweaking my new legal garden, as I can do what i need the right way and not have to skimp on quality construction to be able to tear it down at a moments notice. Lol at any rate I am running 2 400 watt hps in my flower room and to cool I have a swamp cooler, I am growing in the attic but I have been able to keep the climate right by cycling my lights at night keeping my swamp cooler full and by sucking cool night air in from the window through ducts ive created. As I said I have no problem keeping the room at the right humidity temp and all that but if i switch the fan to exhaust it gets hot and sucks all the humidity out, so I just bring cold air in and allow for passive air movement through the open flower room door when the lights are on, I guess what Im getting at is will this create a problem since i have no real exhaust, or am I just lucky to live in colorado where it gets cool every night in the summer. thanks for any input it is greatly appreciated

Don't quite get it. You say you switch your fan to exhaust, but you have no real exhaust?

If you are using a swamp cooler to blast cool air into your grow, you don't need an exhaust, just cut some relief holes to let out the air introduced by the cooler. Just keep an eye on humidity because swamp coolers increase it quite a bit.

i have two in line fans that I wired to a switch to change the polarity to change directions. So I can change from intake to exhaust with a flip of the switch, what im saying is, when i have them both on exhaust for some reason they seem to suck out more air than the cooler can replace, and it actually gets hotter and kills all the humidity by about 40 percent than what it does with just having the door open and the fans sucking cool air in from outside. I was just making sure that I wasnt going to create any problems with stagnant air. I live in colorado and the humidity is usually about 12-15 percent every day so its really dry which turns out to be a blessing when it comes to controlling humidity using the evap cooler Its consistently between 50 55%.