Best No-Drill Blackout Blinds

This is the most oversold word in window coverings. Blackout gets used for anything darker than a net curtain, and buyers who want to sleep past sunrise end up disappointed by products that never claimed what they were bought for. The two products here do publish a number, which puts them ahead of most of the category -- and the number still does not mean what people read it to mean.

What 99 percent actually describes

It describes light passing through the material. Hold the fabric up and one percent of what hits it comes out the other side. That is a genuine and useful property, and it is why a blackout shade in a window looks like a dark rectangle rather than a gray one.

It says nothing about light passing around the material. An inside-mounted shade sits within the window opening, narrower than the opening by the clearance it needs to raise and lower. Along both vertical edges there is a gap. In a west-facing bedroom in June, that gap is a bright line up each side of the window and a wash of light across the ceiling, and it is entirely unaffected by whether the fabric blocks 99 percent or 100.

Closing the gap, in order of cost

This is the part that actually determines whether the room gets dark, and none of it is exotic.

1. Mount outside the frame instead of inside

The paper shades publish that they can be trimmed for a fit inside or outside the window frame. Mounted outside -- on the flat wall or the face of the casing, overlapping the opening on both sides -- there is no side gap at all. It looks less tidy, it costs nothing extra, and it is by a wide margin the most effective thing on this list. The cellular fabric shade cannot do this: it is inside mount only.

2. Add a curtain over the shade

A curtain hung wider than the opening catches everything the shade misses, and the shade stops the curtain having to be blackout-lined. In a rental the hardware is the constraint, not the fabric: a no-drill bracket that taps into wooden trim publishes 20 lb, and a tension rod inside the reveal publishes up to 22 lb. Both are covered in best no-drill curtain rod brackets.

3. Two shades, side by side, overlapped

On a wide window, two narrower shades overlapping in the middle beat one wide one, because you can bias each toward its own edge. The paper shades come four to a pack, which makes this cheap enough to be worth doing.

4. Accept it and treat the ceiling

Most of what wakes people is not the bright line at the window edge, it is the light bouncing off a pale ceiling above it. A shade mounted as high as the reveal allows aims the leak downward rather than up, which is a free improvement and takes ten seconds to get right at install.

Cellular fabric against paper, at the same published figure

Both reach 99 percent, so the choice is made on everything else.

The cellular shade has a cordless lift mechanism, finished edges and a 9/16 inch honeycomb that traps an air layer -- which matters in a rental with single glazing, because a cold window is a comfort problem as well as a light one. It is inside mount only, so it cannot use the outside-mount fix above, and it needs 1-1/4 inches of reveal depth.

The paper shade is a fraction of the price, comes four to a pack, and can mount outside the frame -- which, given everything above, means it can produce a darker room than the more expensive product. What it costs you is durability and appearance: it raises on clips rather than a lift mechanism, and paper creases.

For a bedroom in a one-year rental where darkness is the whole point, the paper blackout shade mounted outside the frame is the better buy, and it is a genuinely unusual case of the cheap option winning on the thing that matters. For a room you also want to look at, the cellular shade inside the reveal with a curtain over it is the better system.

Why the room-darkening shade is in this comparison

Because it is the one people buy by mistake. It sits next to the blackout version, costs the same, and looks similar in a photograph. The difference is on the label: it publishes block a majority of light, with no percentage, where the blackout publishes 99 percent.

That is not a defect. Room darkening is exactly right for a living room where the goal is glare control and a bit of privacy, and gray reads better against most casings than black does. It is simply not the product for a bedroom, and the maker is not the one implying otherwise. Read the label rather than the category.

The verdict

If the room must be dark and you can live with the look: paper blackout shade, published 99 percent, mounted outside the frame with an overlap on both sides. Cheapest and darkest.

If it must be dark and look finished: cellular blackout shade inside the reveal, plus a curtain on no-drill hardware to cover the edges. Two products, and honestly the only combination here that gets a rental bedroom properly dark.

If you just want the television watchable in the afternoon: the room-darkening shade, and do not pay for blackout you do not need. The rest of the no-drill shade range, including the light-filtering options and the bracket that converts a stock roller shade, is ranked in best no-drill blinds.