Top-Hung & Bottom-Hung Windows 

(Awning and Hopper Window Systems)

Top-hung and bottom-hung windows are specialized operable window types engineered for secure, space-efficient ventilation in constrained or high-safety environments. Each features a fixed hinge axis—mounted along the top or bottom edge of the sash—allowing the window to pivot inward or outward within a strictly limited arc.

   · The top-hung window (commonly referred to as an awning window when opening outward) is hinged at the head of the frame. It typically opens outward from the bottom, creating a sheltered ventilation gap that remains functional even during light rain.

   · The bottom-hung window (hopper window) is hinged at the sill and usually opens inward from the top, ideal for interior-facing applications or locations requiring easy cleaning from inside.

Both configurations are equipped with adjustable friction stays or security restrictors—often colloquially called “chains”—that limit the maximum opening to approximately 10 cm (4 inches). This deliberate constraint ensures continuous airflow while preventing unauthorized entry, making these windows exceptionally well-suited for urban dwellings, ground-floor rooms, bathrooms, kitchens, and homes frequently left unattended.

Key Advantages

   · Enhanced Security Without Sacrificing Ventilation: The restricted opening allows fresh air circulation while acting as a physical deterrent against intrusion—ideal for safety-conscious households.

   · Minimal Spatial Footprint: Unlike casement or swing windows, these units require no clearance for full sash rotation, making them perfect for compact spaces such as kitchen countertops, bathroom vanities, or narrow corridors.

   · Weather Resilience (Top-Hung/Awning Type): When opened outward, the sash acts like a shield, deflecting rain away from the opening—a practical solution for exposed façades.

   · Ease of Operation & Maintenance: Simple hardware mechanisms ensure reliable performance over time; inward-opening bottom-hung variants allow convenient interior-side glass cleaning.

   · Architectural Discretion: With clean lines and subtle operation, these windows integrate seamlessly into modern, minimalist, or heritage-sensitive designs without visual clutter.

Widely specified in residential, multi-family housing, and institutional projects, top- and bottom-hung windows exemplify intelligent design: where every centimeter of space and every degree of openness is purposefully calibrated for safety, comfort, and efficiency.