Three window styles cover almost every UK home. Casement windows hinge at the side and open outwards. Sash windows slide vertically and belong on period houses. Tilt and turn windows open two ways, tilting in at the top for ventilation or swinging fully inwards. Each has a job it does best.
Points to take away
- Casement: cheapest, simplest, best all-rounder for most homes.
- Sash: for Victorian, Edwardian and Georgian houses, and usually required in conservation areas.
- Tilt and turn: secure night ventilation, easy cleaning from inside, good for large single sashes and upper floors.
- Check the escape-window rule for habitable rooms above ground floor.
- In a conservation area, the planners may decide the style for you.
Reading time: about 6 minutes.
Casement windows
A casement is side-hinged and opens outwards like a small door. When shut, the sash presses onto a seal all the way round, which is why casements are weathertight and thermally strong. They are the most common style in the UK and the cheapest, at roughly £350 to £600 fitted in uPVC.
Good at: sealing, ventilation, cost, keeping the open sash clear of curtains and furniture inside.
Weak at: cleaning the outer glass on upper floors without easy-clean hinges, opening over a narrow path or busy pavement, holding a very large single pane (the stay limits how big a casement sash can safely be).
Top-hung and side-hung casements are often combined in one frame: a fixed pane plus an opener, or two openers with a mullion between.
Sash windows
A sash window has two panels that slide vertically past each other in the frame, counterbalanced by weights or springs. They define the look of Georgian, Victorian and Edwardian houses, with slim glazing bars and tall proportions that a casement cannot copy.
Older timber sashes earned a reputation for draughts, sticking and endless painting. Modern versions, in engineered timber or in uPVC and aluminium “sliding sash” designs, add brush seals, better balances and, in the non-timber versions, low maintenance. uPVC sash runs £700 to £1,500 fitted.
Good at: period authenticity, ventilating from top and bottom at once, opening without projecting inside or out.
Weak at: cost, and the fact that only half the window opening is ever clear. Cleaning the outer glass needs tilting sashes or access from outside.
Tilt and turn windows
A tilt and turn has one handle and two modes. Turn it one way and the whole sash swings inwards from a side hinge, like an inward casement, for full opening, cleaning and escape. Turn it the other way and the top of the sash tilts into the room a few centimetres for controlled background ventilation.
The design is standard across Germany and Austria and has grown in the UK. uPVC tilt and turn runs £450 to £750 fitted, so £100 to £300 more than a casement of the same size.
Good at: secure ventilation (the tilt position is hard to force from outside, so it is safe to leave overnight or when out), cleaning both glass faces from inside, holding large single sashes because the hinges carry the weight, meeting the escape-window rule upstairs.
Weak at: the inward swing, which clashes with curtains, blinds and anything on the sill, so it needs planning around furnished rooms.
The escape-window rule
Any habitable room above the ground floor (and basement rooms) needs at least one window that can be used to escape a fire. Building Regulations set a minimum clear opening of roughly 0.33 square metres, at least 450mm each way, with the base no higher than 1.1m above the floor.
A side-hung casement usually meets it. The turn function of a tilt and turn meets it. A small top-hung opener or a narrow sash often does not, so on bedrooms and similar rooms upstairs, the style has to allow a big enough opening. Your installer should size this correctly, and a FENSA or CERTASS registered one certifies it.
Which style for your house
- Any home, sensible budget, most rooms: casement.
- Victorian, Edwardian or Georgian, front elevation: sash. Timber if in a conservation area, uPVC or aluminium sliding sash elsewhere.
- Upstairs bedrooms, or rooms where you want safe night airflow: tilt and turn.
- Large picture windows or a single wide opening: tilt and turn, or an aluminium casement, for the structural span.
- Windows over a path, pavement or patio where an outward sash would be in the way: tilt and turn.
- Conservation area or listed: whatever the planners require, confirmed before you order.
Our double glazing cost guide has fitted prices for each style, and uPVC vs aluminium vs timber covers the frame material choice.
Get a free quote and we will match you with vetted local installers for the style you want.