Louvers and gable vents are composed of angled slats or strips, spaced apart to allow for air flow. Originally, these permitted ventilation in attic spaces; today, they are used both for functional and decorative purposes.

Functional louvers contain screens to allow air passage while filtering insects and dirt.

Non-functional louvers are decorative; they do not allow air flow.

Louvers can be enhanced with trim to add another layer of detail.