The Problem with Most “Blackout” Products

The word blackout is one of the most misused terms in the window treatment industry. A blackout fabric — a roller blind fabric rated EN 13120 Class 3 — transmits zero light through the fabric itself. But in most installations, the fabric is only part of the equation. Light enters around the sides, over the top and under the bottom of the blind. On a bright summer morning, a standard roller blind with a blackout fabric will still allow significant light into the room.

True blackout requires three things: a blackout-rated fabric, an installation system that eliminates edge gaps, and — ideally — a complementary layer such as blackout curtains or shutters to handle any residual leakage.

Blackout Standards

European standard EN 13120 classifies window coverings by their light exclusion:

  • Class 0: No light reduction — sheer fabrics
  • Class 1: Some light filtering
  • Class 2: Significant dimming — suitable for reducing glare and early morning light
  • Class 3: Blackout — defined as less than 0.1% light transmission through the fabric

Only Class 3 products should be marketed as “blackout”. When specifying for hotels, NHS facilities or shift workers, always confirm the EN 13120 Class 3 rating.

Products That Achieve Genuine Blackout

Cassette Roller Blinds with Side Channels

Best overall blackout

An enclosed aluminium cassette at the top conceals the roller mechanism. Side channels run the full height and grip the fabric edges, eliminating side gaps. The most effective roller blind blackout system available.

Blackout Curtains with Return

Most elegant solution

Full-length curtains in blackout-lined fabric, hung on a track that extends beyond the window reveal on both sides. When drawn, the fabric wraps around the wall, eliminating side light. Combined with a pelmet, this is the most elegant blackout solution.

Shutters with Blackout Blinds

Maximum versatility

Plantation shutters do not achieve blackout on their own. Combined with a behind-shutter roller blind in Class 3 fabric, you get both the aesthetic of shutters and functional blackout. Popular in hotel refurbishments.

Blackout Roman Blinds

Aesthetic option

Roman blinds in blackout-lined fabric can achieve near-blackout when fitted within the window reveal. For complete blackout, a fixed timber batten board at the top and side returns in the lining maximise light seal.

The Edge Gap Problem

A standard roller blind hanging in front of a window has gaps on both sides between the fabric and the window frame. Even with a blackout fabric, early morning sun at a low angle can send a shaft of light through a 5mm gap. Solutions:

  • Side channels / guide rails: The fabric edges run inside channels fixed to the wall, sealing the gap completely. Standard on hotel-grade roller systems.
  • Face-fix installation: The blind is fixed to the face of the wall, overlapping the window reveal on all sides. 100mm on each side is a common standard.
  • Blackout lining with return: For curtains, the lining extends around the leading edge of the track to the wall.
  • Fixed boards (batten boards): A timber or MDF board fixed above the window. The blind or curtain hangs from or in front of the board, which blocks any gap above.

Applications

Master Bedrooms

The typical specification is blackout-lined curtains on a silent glide track with a full return, combined with a cassette roller blind in 3% openness fabric behind. Motorised systems mean both can be operated from the bed.

Hotel Guest Rooms

Hotel operators require EN 13120 Class 3 certification — it affects brand standards and guest reviews. The standard hotel specification is a cassette roller blind with full-width side channels plus a sheer voile for daytime privacy.

Children’s Bedrooms and Nurseries

Blackout is a genuine health and wellbeing requirement here. Studies consistently link light exposure during sleep with disrupted melatonin production in children. Battery motors allow operation without a child reaching for a cord.

Media Rooms and Home Cinemas

Screen projection requires complete darkness. The specification here is fixed motorised roller blinds with side channels on all windows, supplemented by light-proof curtains on any glazed doors.

Need genuine blackout? We survey every project and advise honestly on what your installation requires. Request a consultation or visit our Hailsham showroom where we can demonstrate the difference between blackout systems.