 ventilation for incoming air, which is usually around your soffits. But if you don't have that balanced out, it's going to pull more. And then all of a sudden it's going to pull cool air out of your house. And people are going, why is my house hotter when I turn that on? It's because it's pulling cold air out of your house and sending it outside. Yes, you did reduce the attic temperature, but you reduced it by pulling out the cold air that's in your house.