It sounds like you measured the garnish on your existing roof vent to get the 16" x 16" measurement. More than likely you have a standard 14" x 14" opening that would allow you to use the Fan-Tastic Vent Roof Vent # FV807350. This fits a rough opening size of 14-1/4" x 14-1/4". It features a powered vent, powered lift, thermostat, and rain sensors. It also comes with a remote for operation. view full answer...