Blackout Blind or Curtains: What to Choose for Total Darkness
For total darkness, both a blackout blind and blackout curtains can do the job, but the real question is not the fabric, it is the light halo: a standard roller blind lets light through on the sides, and only a blind with side channels or a curtain cut wider than the window removes those leaks. The made-to-measure curtain adds thermal insulation, noise reduction and decor on top, with no drilling.
The Kurtens 3-in-1 curtain blocks 100% of light through its 620 gsm fabric, and holds back up to 7 °C of difference*. Cut with an overlap on the sides and down to the floor, it delivers near-total darkness while dressing the window, where a blind stays a single-function technical solution.
The real challenge of blackout: the side halo
A fabric can block 100% of light and still leave the room lit. The reason is mechanical: light goes around the panel on the sides, the top and the bottom. This is the halo, the number-one flaw of blackout, and it depends on sizing, not just on the fabric.
A roller blind fitted inside the recess leaves a gap of a few millimetres on each edge, enough to light a bedroom at daybreak. A standard curtain that is too narrow does the same. The fix is identical in both cases: cover wider than the opening. For the blind, that means side channels; for the curtain, an overlap and a floor-length drop.
Comparison table: blackout blind or blackout curtains
Three configurations give three results. Here is the honest comparison.
| Criterion | Standard roller blind | Blind with side channels | Made-to-measure blackout curtain |
|---|---|---|---|
| Side halo | Yes, side leaks | No | No, with overlap |
| Total darkness | Partial | Yes | Yes |
| Thermal and acoustic | Low | Low | Yes, 620 gsm, up to 7 °C* |
| Fitting | Drilling the frame | Drilling the frame | Rod, no drilling |
| Style | Technical | Technical | Decorative, warm |
| Reversible | No | No | Yes |
*Data obtained under optimal test conditions. Real darkness depends on the overlap and the fitting.
The blackout blind: strengths and limits
The blackout roller blind is compact, discreet and does not intrude into the room. For total darkness, however, you need the version with side channels, which blocks light on the sides but looks technical, is fixed by drilling the frame, and only blocks light: no notable thermal or acoustic benefit. It is a good solution when space is tight and decor comes second.
The made-to-measure blackout curtain: darkness and versatility
The blackout curtain plays on two fronts. With a fabric that blocks 100% of light and a sizing wider than the window, it removes the halo and plunges the room into darkness. But it does more: a dense 620 gsm fabric also insulates from heat, up to 7 °C of difference*, dampens noise, and dresses the window instead of showing a mechanism. It hangs on a rod, with no drilling, and stays reversible. Discover the blackout curtains collection.
To tell apart the levels of curtain opacity, see blackout, dimout or opaque curtains, and for the choice between plain and thermal blackout, thermal blackout vs plain blackout curtains.
Getting total darkness: the question of overlap
For a child's room, a night worker's bedroom or a home-cinema corner, the goal is complete darkness. With a curtain, the rule is simple: cut wider than the window, plan an overlap in the centre if there are two panels, and run down to the floor. As the Kurtens fabric already blocks 100% of light, it is this overlap that makes the difference between a dark room and a truly black one. For extreme exposure, layering a blind and a curtain removes the last leaks.
How much does each solution cost
A standard blackout roller blind is inexpensive, but the version with side channels, the only one to guarantee total darkness, raises the price and demands a precise fit. The made-to-measure blackout curtain costs the price of a curtain, fitted yourself on a rod, and serves several functions at once: blackout, thermal, acoustic and decor. Relative to the number of benefits, it is often the most cost-effective solution, especially when renting and drilling is to be avoided.
The Kurtens blackout curtain
The Kurtens 3-in-1 curtain blocks 100% of light, weighs 620 gsm and holds back up to 7 °C of difference*, while dampening noise. Cut to measure to the exact dimensions of the window, with the necessary overlap, it removes the side halo and delivers near-total darkness, with no drilling and reversibly. Configure yours in the blackout curtains collection.
Frequently asked questions
Blackout blind or curtains for total darkness in a bedroom?
Both can do it, as long as the side halo is removed: a blind with side channels, or a curtain cut wider than the window with an overlap and a floor-length drop. The curtain also adds thermal insulation, noise reduction and decor, with no drilling.
Why does my room stay lit despite a blackout fabric?
Because light goes around the panel on the sides, top or bottom. A fabric that blocks 100% of light is not enough if the blind or curtain is fitted too tight. The fix is to cover wider than the opening: side channels for the blind, an overlap for the curtain.
Does a blind block light better than a curtain?
At equal sizing, no. A blind with side channels and a made-to-measure curtain with an overlap both deliver total darkness. The difference is elsewhere: the curtain also brings thermal, acoustic and decorative benefits, and fits with no drilling.
Can a blind and a blackout curtain be combined?
Yes, this is layering: a blind in the recess and a curtain over it remove the last light leaks. It is useful on a very exposed window or for sensitive sleep, but a well-sized made-to-measure curtain is enough in most cases.
Which curtain to darken a baby's room?
A curtain with a 100% blackout fabric, cut wider than the window and running to the floor, to remove the halo. A dense 620 gsm fabric also brings useful thermal insulation to regulate the room temperature, in summer and winter.
Is a blackout curtain suitable for a rental?
Yes, more than a blind. Hung on a rod, with no drilling of the frame, it is fitted and removed freely, whereas a blackout blind with side channels is fixed by drilling. When renting, the made-to-measure curtain is the most flexible blackout solution.
Key takeaways
Blind or blackout curtain, total darkness is a question of sizing before it is a question of product: the side halo has to be removed, with side channels for the blind or an overlap for the curtain. At equal blackout, the made-to-measure curtain wins on versatility: it blocks light, insulates from heat up to 7 °C of difference*, dampens noise, dresses the window and fits with no drilling. Configure yours in the blackout curtains collection.
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