Casement, sliding or tilt-and-turn: picking the window type

The opening style is usually set by the architect, but when it is left to the fabricator, match it to the room and the elevation — not habit.

Casement (side or top-hung)

Opens outward on friction stays. Best rain and air seal of the three because the sash pulls onto a continuous gasket. Wants a clear swing outside, so it is awkward over a busy walkway or a narrow duct. Hardware: friction stays, a locking handle or multi-point lock, restrictor if it is upstairs.

Sliding

Sashes run past each other on rollers. No swing, so it suits balconies, kitchens over a counter, and tight external spaces. The seal is an interlock and brush pile rather than a compression gasket, so it is a little less airtight — fine for Bengaluru, less so on a high, exposed tower face. Hardware: roller carriages sized to leaf weight, touch or hook locks, anti-lift blocks, bottom guides.

Tilt-and-turn

One handle position tilts the sash in at the top for secure trickle ventilation; another swings it fully in like a door for cleaning and escape. Excellent seal, very secure, cleaned from inside — which is why it dominates apartment towers. The trade-off is cost and the inward swing eating room space. Hardware: a tilt-and-turn mechanism set matched to the sash size, plus the handle and hinges.

A quick rule

• Bedrooms and studies on a noisy road: tilt-and-turn or casement.
• Balconies, kitchens, utility: sliding.
• Upper floors where cleaning access matters: tilt-and-turn or an easy-clean casement.

Send the elevation and the room use and we will spec the mechanism for whichever style you land on.