The top-selling attic fan manufacturers are Empire, Dayton and Broan, according to Grainger Industrial Supply. On Amazon.com, the top-selling manufacturers are Empire, Lomanco, Broan and Cool Attic, as of March 2015.
Empire and Dayton attic fans hold 10 of the top 16 spots in Grainger's best-selling attic fan ranking. Two of Grainger's top listed fans are made by Broan.
An Empire attic fan is the most popular on Amazon.com, followed closely by Lomanco and Cool Attic fans. Several Broan models are also represented, though they do not sell as well as the other brands. Ventamatic attic fans also make Amazon.com's list of top sellers.