To feel the full effect of evaporative cooling, the cooled air needs to pass through and out of the house. The Up-Dux Ceiling Vent exhausts this evaporative air through the attic. As a result, attic temperatures are lowered instead of cool air passing through open windows or doors. The pre-assembled Model DL-101 is ideal for homes with up to 6 in. of ceiling insulation. For optimum results, install one Up-Dux Ceiling Vent in every major room to be cooled.