Obscure glass is glass that lets light through but blurs or hides the view, used in bathrooms, toilets, landings, front-door side panels and side windows that face a neighbour. “Frosted glass” is the everyday name for it. Most obscure glass is textured, with a pattern rolled into the surface, and the patterns are graded by how much they hide: Pilkington, for example, groups its textured designs into five privacy levels, from 1 (least obscuring) to 5 (most). In a new window the obscure pane is built into the sealed double-glazed unit, so it is as warm as clear glass. This page explains how to choose a level and what the rules say. For the windows themselves see UPVC windows and doors and aluminium windows.
Privacy levels explained
Pilkington’s Texture Glass guide places its designs on a scale of 1 to 5, with examples at each level:
- Level 1: least obscuration, for example Warwick. Shapes and colour are still visible.
- Level 2: for example Minster, Sycamore, Oak and Reeded.
- Level 3: for example Taffeta, Autumn and Digital.
- Level 4: for example Stippolyte, Mayflower, Contora and Charcoal Sticks.
- Level 5: greatest obscuration, for example Arctic, Cotswold, Everglade and Tribal.
The higher the number, the less you can make out through the glass, especially when the light is brighter on one side. At night, with lights on inside, people outside can see more through any obscure glass than they can in the day, so for bathrooms we usually suggest level 4 or 5. For a hall or landing where you want light and only a softened view, level 2 or 3 is often enough. We bring samples to the survey so you can judge them in your own light.
Other ways to get privacy
- Satin or acid-etched glass. A smooth, evenly frosted finish rather than a pattern. It looks clean and modern and is easy to wipe. Ask us which finishes are available for your unit.
- Partial obscuring. Obscure glass in the lower pane only, with clear glass in a top light, keeps privacy at eye level while letting you see sky.
- Decorative etched designs. Bands, borders or patterns that obscure part of the pane. See our decorative glass page.
- Blinds. For rooms where you only want privacy sometimes, clear glass with blinds or shutters may suit better.
Stick-on frosting film is a cheap short-term fix, but it can peel and bubble and does not count as obscure glazing where a planning condition requires it.
Obscure glass in bathrooms
Bathrooms are the most common use. Points to think about:
- Privacy level. Level 4 or 5 for windows next to baths, showers and toilets.
- Safety glass. Bathroom windows are often low, especially above a bath. Approved Document K sets the rules for glazing in critical locations; councils such as Richmond summarise these as glass within 800mm of the floor, glass in doors up to 1500mm, and glass within 300mm of a door up to 1500mm. Obscure glass in those zones must be toughened or laminated. Textured glass is available toughened.
- Ventilation. Bathrooms need good ventilation to control condensation. A top-hung vent with obscure glass opens for air without exposing the room. Trickle vents help too.
- Cleaning. Deeply textured patterns can hold soap and limescale on the room side. A smoother pattern or satin finish is easier to keep clean.
Side windows and the 1.7m rule
If you are adding or replacing upper-floor windows on the side wall of a house, planning rules come into play. The Planning Portal says that for permitted development, new windows in an upper-floor side elevation must be obscure-glazed and either non-opening or more than 1.7 metres above the floor of the room. In practice that means either a fixed obscure window, or an obscure window where only the part above 1.7m opens, for example a high top light.
Many extensions also carry a planning condition requiring particular side windows to be obscure-glazed, sometimes to a stated minimum privacy level. Check your decision notice before changing any glass, as swapping obscure for clear glass could breach the condition. If your house is listed or in an Article 4 area, check with the council first. See our planning permission guide for the wider rules.
Front doors and side panels
Glass in and beside front doors is usually obscure for privacy, and because it is in a door or within 300mm of one, it must also be safety glass up to 1500mm. See our front doors and composite doors pages for door glazing options.
Energy performance
Obscure glass is simply one pane of the sealed unit, so it can be combined with low-emissivity glass and warm-edge spacers in the same way as clear glass. Replacement windows still need to meet 1.4 W/m²K or band B under Approved Document L. For noisy sides of the house, obscure glass can also be combined with acoustic laminated glass; see sound reducing windows.
Common mistakes
- Choosing a low privacy level for a bathroom and finding it too revealing at night.
- Forgetting toughened glass for a low bathroom window or a door side panel.
- Fitting a fully opening side window on an upper floor and losing permitted development.
- Mixing different obscure patterns on the same elevation, which looks untidy from outside.
Caring for obscure glass
Clean textured glass with warm soapy water and a soft brush or cloth to reach into the pattern, then rinse and dry. Avoid abrasive pads, which can scratch satin finishes.
Get advice and a quote
We fabricate aluminium windows from £400 at our Fifield workshop near Windsor and supply UPVC on the Selecta Advance 70 system, with lead times from 10 days and a 10-year guarantee, across Berkshire, Buckinghamshire, Surrey, west Kent and north West Sussex. Call 01753 965 005 or request a quote and we will bring obscure glass samples to your free survey.
Frequently asked questions
What is the difference between obscure and frosted glass?
In everyday use they mean the same thing: glass that lets light in but blurs the view. Obscure glass usually has a textured pattern rolled into the surface. Frosted often describes a smooth satin or acid-etched finish. Both can be built into a double-glazed unit and are available in toughened versions for safety.
Which obscure glass privacy level is best for a bathroom?
Level 4 or 5 on the Pilkington scale is the usual choice next to baths, showers and toilets, because more can be seen through obscure glass at night when lights are on inside. Level 2 or 3 suits halls and landings where you want light and a softened view rather than full privacy.
Do upper-floor side windows have to be obscure glass?
Under permitted development, new windows in an upper-floor side elevation must be obscure-glazed and either non-opening or opening only above 1.7 metres from the floor. Some extensions also have planning conditions requiring obscure glass. Check your decision notice and your council before changing side windows.
Does obscure glass need to be toughened?
Only where it is in a critical location under Approved Document K: within 800mm of the floor, in a door up to 1500mm, or within 300mm of a door up to 1500mm. Low bathroom windows and front door side panels often fall into these zones, so we specify toughened or laminated obscure glass there.
Is obscure glass less energy efficient than clear glass?
No meaningful difference in a modern window. The obscure pane is one layer of a sealed double-glazed unit and can be combined with low-emissivity glass and warm-edge spacers. Replacement windows with obscure glass must still meet 1.4 W/m²K or Window Energy Rating band B under Approved Document L.