The best uPVC window types: which opening suits which room

"The best type" has no general answer. The right type depends on the opening: how large is it, is there room to open inwards, and what is your priority — ventilation, insulation, or the widest possible view?

Casement

The tightest and best-insulating type, because the sash compresses against the gaskets when closed. Premier's casement systems use four TPE gaskets, and the Frankfort Casement 70 leads with six chambers, Uw 1.18 and Rw ≥ 40 dB. Best for bedrooms and noise-exposed elevations.

Tilt and turn

The same casement profile with hardware that allows two positions: full opening for cleaning, and a tilt position for safe ventilation without swinging the sash open. Useful on upper floors and where there are children.

Sliding

Takes no room inside the space, and is the answer for wide openings and balconies. Premier's sliding systems: SETI 100 at 100 mm, Frankfort 120 at 117 mm and Frankfort 140 at 137 mm with three glass sashes for the widest opening.

Integrated fly screen

The SETI Sliding 100 and Frankfort Sliding 120 provide a fly-screen sash integrated into the system itself, rather than an external screen added afterwards.

Acoustic and thermal performance do not come from the opening type alone: the glass build-up and the quality of installation into the opening matter just as much.

The figures above come from Premier's technical catalogue. Final pricing and availability are confirmed by the Premier team against your actual sizes and quantities.