The question is, have you saved any money? I doubt it, as the majority of the heat gain through the ceiling is from radiant heat. Lowering the air temperature in the attic saves very little energy. The only way it makes financial sense is if the vents are solar powered and don't cost you anything to run. You can read the details in the attached file. Of course, there may be other good reasons to increase attic ventilation in a heating climate, especially if you can't control the humidity indoors. Download Attachment: Attic Vent Report Final.pdf 1990.69 KB