A grill window refers to a security or decorative metal grill (usually iron, steel, or aluminium) placed within or on the uPVC frame, providing protection against intruders.
A mesh window (or insect screen) uses a fine mesh (insect screen) to prevent insects from entering, while allowing air flow.
In a combined system, you can have both: a security grill + insect mesh + the main glass window sash. Koemmerling, for example, has a Grill & Mesh Casement Window that provides both safety and insect protection.
The mesh sash can be inside (behind or in front of grill) depending on design, so you can open the glass-sash / mesh-sash independently.
Security
Grill provides a strong barrier against break-ins.
Can be integrated into the uPVC frame for a clean look and stronger structure.
Ventilation + Insect Protection
Mesh allows air in while keeping mosquitoes, flies, and other insects out.
Especially good for Indian homes where you want to keep windows open but avoid bugs.
Durability
uPVC frame is low-maintenance, weather-resistant.
Mesh options can be rust-resistant (fiberglass, stainless steel).
Aesthetic Flexibility
Grill designs can be decorative or security-focused.
Mesh types & styles (pull-down, pleated, sliding) offer design flexibility.
Price: