Penthouses - Roof Louvers for HVAC

Need roof louvers? Your project may have ventilation points on a flat rooftop. Protect these points with penthouse louvers. Learn more on the Newsstand.

Protecting Rooftop Openings

Ventilation points are common features along the walls of a building. These places are typically the intake and exhaust points of the building’s HVAC system. Louvers will protect these openings from harmful elements, like rainwater and debris, while allowing air through the opening.

What if the ventilation point is on the roof of the building? Intake and exhaust points are common roof features. This method is known as gravity ventilation. A standard louver would be mounted vertically, allowing rainwater to pass through its free area and into the ductwork below. It won’t work in these instances. You need a roof louver, also known as a penthouse, to keep your ductwork dry.

Penthouse Construction and Customization

A penthouse is an assembly consisting of four panels and a roof. Standard penthouses are highly customizable, providing options for the four panel walls, the roof, and the corners of the panels. The four panels can be customized to match the needs of the application. You can choose louvered panels on each side of the penthouse to maximize airflow into the opening. Or you can have louvered panels on opposite sides, if you need the ventilation point for intake and exhaust flow.

For standard penthouses, panels can be any size you need to accommodate any roof opening. The penthouse should be large enough to cover the opening. Manufacturers may also offer their other louver models as panel options for the penthouse. 

In these instances, you can choose drainable louvers to prevent rain from infiltrating the penthouse. When equipped with the right panels, penthouses are roof louvers that provide protection for ventilation points on the roof. You can also choose severe weather louvers for guarding against wind driven rain.

While the louvers will be rated for severe weather, the penthouse assembly will not carry the same rating.  This is an important distinction to make when considering hurricane-rated penthouses. Adding hurricane louvers to the penthouse will not make it a “hurricane penthouse”. There are additional aspects to consider when meeting hurricane requirements. The full assembly must be approved for use in hurricanes by the Florida Building Code or by AMCA’s standards for hurricane louvers. 

You can also add a hatch on one side to provide access to the interior of the penthouse. You can also choose a panel with a glass viewport, for applications that require you to see into the penthouse. Doors and viewports are useful options for maintaining a damper installed in the roof opening. Certain penthouses will come with a curb attachment that has an access door. Be sure to check the penthouse submittal to see your available options.

Corners and Roofs

Penthouse corners can be post capped or miter welded, depending on the look you want. For mitered corners, the blades from each panel will come together at the corner. This creates a continuous look from panel to panel. Mitered corner pieces are assembled at the factory and are joined to the louver panel during the installation process.

Post corners have a metal cover that creates a discreet corner piece between the panels. The post corner accepts the louver blades from the adjoining panels. This design provides support for the louver blades while creating a sturdy, square look to the finished penthouse.

Mitered corners have similar supports in place for the louver blades. Mitered corners are commonly reinforced with metal angles that sit behind the blades. Both corner types provide the necessary support for the panels.

This is an example of a penthouse with post corners. 

The roof of the penthouse can be flat or sloped to deflect rainwater. The exact angle and design of the roof may differ between penthouse models, but manufacturers will often allow full customization of the roof to fit your specifications. Once installed, the penthouse will sit over a ventilation opening on the roof to protect the opening from rainfall and other unwanted debris.

Curbs and Throats

Curb and throat attachments are typically included when the penthouse will have a damper for the opening. The curb is a platform that is attached to opening receiving the penthouse. The curb can receive an access door on one side, so that technicians can easily access the damper inside the penthouse.

The curb piece is mounted to the rooftop opening. The penthouse sits on top of the curb.

The throat is a duct assembly that joins the penthouse curb with the duct inside the opening. This connects the penthouse directly to the ductwork. It is common to place a control damper inside the throat, so that operators can control airflow at the ventilation point.

Smoke Evacuation

Penthouses are commonly used for smoke evacuation for elevator shafts. Manufacturers will call these “elevator vents” or “smoke evacuation penthouses”. During a fire event, smoke will gather inside elevator shafts and rise into the upper floors of the building.

Smoke evacuation penthouses are equipped with a UL-rated smoke damper, which opens when smoke is detected in the elevator shaft. This provides an exhaust point for the buildup of smoke in the elevator shaft. You may also utilize a fan system to draw the smoke up to the exhaust point. The smoke evacuation penthouse provides a clear exit for smoke and noxious fumes.

The elevator shaft on the left does not have a smoke evacuation penthouse. The smoke fills the upper floors, endangering occupants. The smoke evacuation penthouse provides an exhaust point for the smoke to leave the building.

Penthouses and Gravity Ventilation

Penthouses protect roof ventilation openings from the elements. When equipped with the right panels, the full assembly will work as a roof louver. As an intake louver, the penthouse can allow for gravity ventilation by allowing air to naturally flow into the opening.

Keep fresh air flowing into your HVAC system while keeping rain and other harmful elements out. Penthouses can be customized to fit the needs of your application.

Starting a new HVAC project? Need louvers to protect your ventilation points? Arrow United Industries can help. We build louvers and penthouses for a variety of applications, from standard airflow louvers to severe weather and hurricane louvers. We can help you meet your project’s needs. Contact Arrow United today and let’s work together on your next project.

Have any experience with penthouse louvers? Tell us in the comments section. We want to hear from you!

For more on louvers and dampers, check out our other Newsstand articles:

• Three Common Types of Intake Louvers
• The Condenser - Water Infiltration and Louvers
• Damper Showdown - Control Dampers vs. Backdraft Dampers
• Parallel or Opposed Blade Dampers? Control Dampers and Blade Action