The idea of a whole house fan sounds too good to be true. The idea that you can replace your AC, which can cost money and energy, with something that's cheaper and efficient, does sound a little bit suspect. If you've ever had AC issues, you may have tried a fan in your room, and while it can bring some relief, you were probably still sweating and struggling to sleep at night during the peak of summer. A whole house fan works excellently if it's cooler outdoors than it is indoors. This especially applies to those who live in a desert environment. It can be hard to get the air outside into your house, even if you crack open all the windows. One reason for this is because the hot air can stay in your attic, and trying to cool down your home while your attic is hot can be a tall order. That's why the whole house fan is so helpful. It does work, especially if you live in the right environment and can install it correctly.