Open vs Closed Gable Louvers: Which Do You Need?
Open louvers have slats that pass air. Closed louvers use the same outline with a solid face behind the slats. They are decorative only. The shape can be identical. The back of the piece is what changes.
Choose open when the vent is part of the attic ventilation plan. Choose closed for curb appeal when the gable is already ventilated another way, or when the wall is over living space and you do not want a hole. Spectis molds both in high-density polyurethane. They ship factory-primed white and are ready for paint. The material does not rot, and it cuts and fastens much like wood trim.
Side by side
| Open | Closed | |
|---|---|---|
| Airflow | Slats pass air. The opening is part of the attic plan. | No airflow. A solid face sits behind the slats. |
| Look | You see through the slats into the opening. | You see the slat shadow on a solid face. From the street it still reads as a vent. |
| Typical use | An unfinished attic that needs this opening. | A gable that is already vented, or a wall over a finished room. |
| Bugs and water | The slats are an air path, so the cut in the wall has to be planned and sealed like any penetration. | There is no air path through the face. You still seal the perimeter where it meets the siding. |
| Where to mount | Over a framed opening smaller than the vent, so the frame laps the cut. | Flat on the wall. No opening is cut. |
The longer write-up is the Spectis guide to open vs. closed gable louvers. The two collections are open gable louvers and closed gable louvers. Shape-by-shape notes are on the shapes page, and the wall sequence is in the install overview.