Blackout shades
Almost every complaint about blackout shades is really a complaint about light leaking around the edges. Getting a dark room is a mounting decision as much as a fabric decision.
Fabric is only half the job
Blackout fabric is opaque — no light passes through it. But an inside-mounted shade has to be narrower than the opening to run freely, so a thin halo appears down each side and along the sill. In a bedroom at sunrise, that halo is what wakes people up.
The three ways to close the gap
- Side and sill channels — aluminium tracks that capture the edges of a roller or cellular shade. The darkest result.
- Generous outside mount — the shade overlaps the trim on all four sides, with a cassette or fascia at the top.
- Layering — a blackout shade under lined drapery, which also softens the room acoustically.
Which type to choose
Blackout roller shades are the simplest and cheapest, and the easiest to fit with channels. Blackout cellular shades add insulation, which matters in a nursery or a cold bedroom. Blackout-lined Roman shades and drapery are the decorative option where the window is a feature and total darkness is a nice-to-have.
What to compare in the photos
- Whether the shade is inside or outside mounted, and by how much it overlaps.
- Presence of side channels or a cassette at the header.
- How the shade is layered with drapery, if at all.
- Bedroom and nursery installs specifically — the rooms where this actually gets tested.
Frequently asked questions
- Why does light still come in around my blackout shade?
- Blackout describes the fabric, not the installation. An inside-mounted shade always leaves a gap at each side; the light you see is going around the shade, not through it.
- How do I get a completely dark bedroom?
- Combine blackout fabric with either side channels and a sill channel, or a generous outside mount that overlaps the opening on all four sides. Nursery installs in the library usually show one of those two solutions.
- Which type of shade blocks the most light?
- A blackout cellular or roller in side channels is the darkest common setup. Blackout-lined Roman shades and drapery soften the room more but leak more light at the edges.
- Are blackout shades good for heat as well?
- They cut solar gain because the fabric is opaque, but insulation comes from trapped air. A blackout cellular does both; a blackout roller mainly blocks light.