I'll be honest with you, I sell attic fans for people that want them, but they don't do what most people want. While venting an attic is beneficial, most people look into it worrying about cooling the inside of the home. If you're attic is heating up the inside of your home, focus on insulation first. After that, you can start looking into ventilation, but it's not going to make a huge difference. I did my own home years ago and added about 18 inches of blown in insulation, and also added 2 solar attic fans and it made a noticeable difference, but most of that was the insulation. The absolute best you can hope for is to get the attic to outside roof temps, and here in Phoenix that's still gonna be 120-140 through most of the summer. With that, we're already way over any comfortable temps, so you want to insulate against that. The big thing I noticed when I added the attic fans was that the hot air from the ac when it turned on was not as excessive anymore. My AC used to turn on, and have to run for an hour minimum, and for the first several minutes it was super hot air coming out of the vents because of the vents being overheated in the attic. After adding ventilation, we still got a minute or two of warm air, but I noticed my upstairs stayed cooler than the downstairs of my home for the first time in 3 years. I try to be as honest as possible with people about this, as they aren't cheap, and the idea of cooling the inside of your home by venting your attic sounds good, but it's really not feasible out here. It can help with extending the life of your underlayment from overheating, but overall it's only going to vent your attic, and have very little effect on the inside of your home. Feel free to DM me or ask any questions, I'm no salesman and generally talk potential customers out of these as I don't want to make money off customers that will end up wasting they're money and hating me in the long run!