Blackout Curtain Liner

Blackout curtain liner in 3-pass acrylic-foam coated 290 gsm cloth, white on both faces, under 0.5% light transmission by spectrophotometer at 550 nm — hooks behind any existing pencil-pleat, pinch-pleat or eyelet curtain in five minutes per panel. Our blackout curtain liner is the cheapest reversible route to blackout, and works as thermal insulation via the still-air cavity it creates.

Keep the curtains you have, add the darkness behind them

Most people who want a dark room already have curtains they chose carefully and do not want to replace. A liner solves that: it hangs behind the existing panel on the same hooks, doing the light work invisibly while the curtain you bought stays the curtain in the room.

The cheapest, most reversible route to blackout

It is also the cheapest route to blackout by a wide margin, and the most reversible — which matters in a rented flat, in a room being redecorated within a couple of years, or when you want to test whether a dark room actually fixes the sleep problem before committing to new curtains.

3-pass, white both sides — deliberately

The liner is 3-pass acrylic-foam coated at 290 gsm, white on the room side and white on the window side, measuring under 0.5% light transmission by spectrophotometer at 550 nm. White on both faces is deliberate: from the street every window in the house reads the same regardless of what colour the curtain in front of it is, which is what stops a house looking patchwork from outside.

Installation: five minutes per panel

It hangs on standard curtain hooks through a woven header tape with three pocket rows, so it fits pencil pleat, pinch pleat and eyelet headings and can be set at three heights to sit just below the top of the curtain. Fitting is one hook every four inches, about five minutes a panel, and it lifts off in less than that.

The thermal side-benefit of a blackout curtain liner

The second thing it does is thermal. A lined curtain traps a layer of still air between the two fabrics, and that air gap is worth more insulation than either layer alone — the same principle as double glazing, at a hundredth of the cost.

Sizes and trim

Widths to fit 52, 66, 90 and 108 in. curtains; drops 54, 72, 84, 90 and 108 in., trimmable at the hem. The liner should finish about an inch shorter than the curtain so it never shows below the hem.

Care

Machine wash cold on its own and hang to dry — never tumble. Because it comes off in a minute, this is the layer that actually gets washed, which is worth something in a window that collects dust and condensation.

Blackout curtain liner size guide

How to care for your blackout curtain liner

• Machine wash cold on its own on gentle
• Hang to dry — NEVER tumble (heat cracks the coating)
• Wash more often than the curtain — it catches window dust and condensation
• Skip fabric softener — degrades the coating

Frequently asked questions

Does a blackout curtain liner really make a room dark?

Yes — the liner delivers under 0.5% transmission on its own, same as any 3-pass blackout curtain. What determines final darkness is how it’s installed (top, sides, hem gaps).

Which curtain headings fit a blackout curtain liner?

All standard headings — pencil pleat, pinch pleat and eyelet. Woven three-pocket header tape and standard hooks.

Does a blackout curtain liner insulate?

Yes — the still-air cavity behind the curtain is what does the insulating (same principle as double glazing).

Can I trim a blackout curtain liner?

Yes — at the hem. Finish an inch shorter than the curtain so it never shows.

Complete the insulation

Pair with your existing linen curtains, add a thermal curtain liner for a second insulating layer, and coordinate with throw pillows.