Sheer vs Blockout Curtains

We get asked this on nearly every first consultation, almost always as an either/or. It isn't. Here's how each fabric behaves in a real Australian house.

What sheer curtains actually do

A sheer is a loosely woven, semi-transparent fabric — voile, linen sheer, textured polyester — that passes light but not detail. On a bright day you'll see the shape of the garden; your neighbour won't see you.

Expect a sheer to cut 10–30% of incoming light. That matters less than what happens to the light it lets through: hard sun becomes even, diffused brightness. It's the difference between glare on a screen at 4pm and a room that simply feels light.

What sheers won't do is give you privacy after dark. Once it's brighter inside than out the effect reverses, and a lit room behind sheers is a display window. No weave is dense enough to fix that.

What blockout curtains actually do

A blockout curtain is either a densely woven opaque fabric or — more often, and better — an ordinary decorative fabric with an opaque lining behind it. The lining does the work. The face fabric does the looking.

A good one blocks 90–100% of light and gives complete privacy day and night. It also does real thermal work: windows are the weakest thermal point in most Australian homes, and a lined curtain cuts summer heat gain and holds warmth overnight in winter.

On noise, be realistic. Heavy interlined fabric softens echo and takes the edge off high-frequency sound. It will not fix single glazing on a main road, and anyone telling you otherwise is selling something.

Sheer vs blockout curtains at a glance

Why most rooms want both

Layering removes the choice. Sheer on the window side, blockout on the room side, each on its own runner, and you get four settings instead of one compromise: both open, sheer only, blockout only, both closed. Reverse that order and the blockout can't seal against the glass.

Two constraints worth checking first. A double curtain track needs 100–120mm of depth, which some shallow reveals and cornice profiles can't take. And two layers stack to roughly twice the width when open — on a 3m window that's a lot of wall covered at each end.

Doubling up costs around 60–80% more than a single layer, not double, because the track and installation are shared.

The part nobody mentions: light comes around, not through

Most light doesn't pass through a blockout curtain. It gets in around it — down the sides, over the top, under the hem. We regularly see homes where an expensive blockout still leaves a bright halo around the window, because the curtain was made to the size of the glass rather than the size of the problem.

Three details decide whether you get genuine darkness:

1. Side returns. The curtain wraps back to the wall at each end. This is most of your light leak.
2. A sealed top. A pelmet, or a track recessed into the ceiling or a bulkhead.
3. Floor length, not sill length.

Get those right with a mid-weight lining and the room goes properly dark. Get them wrong and the heaviest fabric money can buy will still glow at the edges at 6am in January. A curtain measured to the window instead of the wall is measured wrong.

Room by room

• Bedrooms — blockout, no argument; even low light levels interfere with sleep quality. Layer sheers over the top if the room gets daytime use.
• Living rooms — sheers do most of the work. Add blockout if the room faces west, is overlooked at night, or doubles as a media room.
• Kitchens — sheers, if anything. Heavy fabric near cooking holds grease and odours.
• Media rooms — blockout, and budget for a pelmet. On the Gold Coast we fit these with blockout blinds and side tracks instead.
• Bathrooms — neither. Fabric and moisture are a poor pairing; this is shutter territory.

One opinion you won't hear in a showroom: most homes over-specify blockout and under-specify sheers. People buy darkness for rooms they only ever sit in during daylight.

Nurseries and children's rooms

Blockout — and specify cordless or motorised. Corded window coverings are a genuine strangulation hazard for small children. The ACCC mandatory standard requires that no loose cord form a loop 220mm or longer below 1600mm from the floor. In a child's room we'd go further and remove the cord entirely. It's the one upgrade we'd never talk a parent out of.

Frequently asked questions