Sliding Secondary Glazing vs Hinged vs Fixed: Which Opening Style Is Right for Your London Windows?

Sliding secondary glazing is the default opening style for the vast majority of London installations — and for good reason. It mirrors the movement of a traditional timber sash window, needs no swing clearance into the room, and keeps sightlines almost identical to the original. But sliding is not the only choice, and picking the wrong opening style can quietly cost you both dB reduction and daily convenience.

This guide compares the four opening styles specialist installers offer in London — vertical sliding, horizontal sliding, hinged (side or top-hung), and fixed — on acoustic performance, price, ventilation and cleaning access.

Vertical sliding secondary glazing

The natural partner to a timber sash window. Two glazed panels slide vertically on brass or nylon runners, matching the operation of the original sash. Popular in Georgian, Victorian and Edwardian properties across Kensington, Chelsea, Islington and Hampstead.

• Acoustic performance: Up to 52-54dB with 10.8mm laminated glass and twin EPDM seals.
• Cost: £550-£750/window fitted (see pricing).
• Best for: Sash windows, tall reveals, rooms where you want to open the top or bottom for ventilation.

Horizontal sliding secondary glazing

Two or more glazed panels slide horizontally on a track. Ideal for wide casement windows, wide bay windows, and commercial installations where a vertical sash pattern would look wrong.

• Acoustic performance: Up to 50-52dB with 10.8mm laminated glass.
• Cost: £500-£700/window fitted.
• Best for: Modern casements, wide picture windows, bays, home offices, retail units.

Hinged (side- or top-hung) secondary glazing

A single glazed panel hinged on the side or top, closing against a compression seal. Because there is no sliding track to compromise the seal, hinged units can deliver the highest possible acoustic performance for a given glass spec.

• Acoustic performance: Up to 54dB — the peak for secondary glazing.
• Cost: £480-£650/window fitted.
• Best for: Narrow windows, bedrooms and studios where absolute noise reduction matters, windows behind radiators (top-hung).

Fixed secondary glazing

A single non-opening glazed panel. Used where the original window is never opened (stairwells, landings, listed windows sealed for conservation reasons) or where absolute acoustic sealing is critical.

• Acoustic performance: Up to 54dB — matches hinged.
• Cost: £420-£580/window fitted (the cheapest option).
• Best for: Stairwells, landings, high-level windows, rooms where the original sash provides all needed ventilation.

Which opening style should you actually choose?

A quick decision rule based on 15 years of London installs:

• Timber sash window you still want to operate → vertical sliding.
• Wide casement or bay → horizontal sliding.
• Absolute maximum dB in a narrow bedroom → hinged.
• Window you never open (stairwell, high-level) → fixed.

Most London projects end up mixing two or three styles across a single property — sliding in the principal rooms, hinged in bedrooms, fixed on the stairwell. Our residential secondary glazing service covers all four opening types, and every free survey includes a per-room recommendation.

Request a free per-window quote and we will specify the right opening style for each room in your property.