You probably don't have the wind we have here in Ks. My neighbor's fan blades blew off in a storm. To me they sound foolish if you are outside, because you will be blowing hot air around. It might keep the "skeeters" off. LOL

It can take the edge of the heat, we have one and we used it a few times this summer. If you are having someone else build the porch for you, adding fans is going to cost very little compared to what you are paying for it anyway. I guess if you are doing it all yourself it will be a larger percentage. But generally you can get a good fan for under $200 and it's relatively quick for an electrician to wire it up.

Hi Maureen, I live in Florida and we are having a 12 x 22 screen room added. I had the same question when I came upon yours. I think two 42 inch or larger would be best because of two separate sitting areas. I would love your input. Thank you so much!

I have 1 fan for my 11 X 14 ft screened porch. For a 12 X 22, I would go with 2. I live in Illinois and it gets very hot and humid. The fan helps a lot. Even when it's very hot, the air the fan blows is cooler. FYI, the fans have a switch to reverse the direction the blades turn. Be sure to have them going counter clockwise for the warm weather.

zorroslw1, Thank you for taking the time to reply. I do appreciate it and will take your advice. Two fans it is!