Need some Help

Hey people im having a little trouble configuring my ventilation set up. I am looking into getting a vortex 8'' inline fan to direct the hot air out of my room. I am in a attic as of now and temps and humidity can get high at times. 6 feet away from the grow area is my houses chimney that continues out of the house. I saw on jorge cervantes grow dvd a grower chose to have his hot air exhaust through the chimney. Is this a good and efficient way to vent the hot air out of my room? Also will i need to buy a separate inline fan and put it somewhere outside of the room to blow fresh air into the room? I calculated the cfm of the whole attic and its 6,760cf. I know that most inline fans are not made to generate that amount of cfm but could i still get by if i installed the fan just in the 7.5x7.5 grow area? Side notes: Im doing a sea of green set up with 2 250w led grow panels, and 6 2700k cfls. Any suggestions on inline fans based on my set up is greatly appreciated.