i also made a window fixture for my intake, basically its 10mm MDF, i have cut a 150mm hole for my duct to breath through. i painted it same color as the outside frame etc and put a vent on the outside so its flush, doesnt look obvious and stops any light leakage, it fits straight in window frame, i then close the window on it and put a chock against the existing window, you need a sledge hammer to smash it out of the window frame once its locked in. The benefit is fresh cool air from outside without any noise, obvious ducting, danger (security risk ), thieves, etc, fresh air from outside into the tent then im exhausting into a 150mm vent in the roof into the roof space, even thought my tent is inside, inside the tent its like being outdoors. very very happy with the window fixture, its dropped my temps down from around 29c to 24/25c steady as i was intaking from inside the room inside the house, now my temp/fan controller hardly turns on, its leet. Off home now, ill be back shortly.