Bedroom blockout curtains in Pakenham.

Blockout is a fabric claim, not a room result.

A true blockout fabric passes effectively no light through the weave. Either it is a triple weave, with a dense white core woven into the middle of a single cloth, or it is a face fabric with a separate blockout lining sewn behind it. Room darkening or dim-out fabric is a different thing. It cuts the light substantially but still glows when the sun is on it, which is fine for a lounge and useless for somebody sleeping in the day.

But even genuine blockout fabric only blocks the light that lands on it. Everything that gets past the edges arrives in the room regardless. That is why two rooms with the identical fabric can be completely different to sleep in.

The three leaks, in order of severity.

1. The top.

A curtain on an exposed rod leaves an open gap above the heading. Daylight comes straight through it and lands on the ceiling, which then acts like a big soft lamp lighting the whole room. This is the biggest single leak and it is also the one most people never think to look at, because you have to be lying in bed looking up to notice it.

Two fixes. Fit the track hard against the ceiling or into an existing plasterboard bulkhead so there is no gap, which costs nothing extra. Or fit a pelmet across the head of the curtain, $180 to $450 fabric-covered and $200 to $600 in timber or MDF. Both are covered in pelmets explained.

2. The sides.

A curtain that stops in mid air at each end leaves a vertical strip of daylight down the wall. Low morning sun makes this dramatically worse, because it arrives almost horizontally and shines straight past the edge of the fabric into the room. In an east-facing bedroom in Officer in December that strip appears at around a quarter past five.

The fix is a return: the track is bent back to the wall at each end so the curtain carries around and physically meets it. It costs very little and it is the single most cost-effective detail on the whole quote.

3. The centre and the floor.

Where a pair of curtains meets in the middle, the two leading edges have to cross, not merely touch. An overlap arm is a small extension on the track that carries one curtain past the other so they overlap by 50 to 100 millimetres. Without it you get a bright vertical line straight down the middle of the window.

At the bottom, a curtain that stops at the sill lets a pool of light onto the floor and up into the room. Floor length, just brushing the floor, closes it and also stops the cold air path described in the thermal curtains guide.

What shift workers and parents actually need.

There is a real difference between sleeping at night with the curtains shut and sleeping during the day. At night you are blocking a streetlight. During the day you are blocking direct sun that moves around the house and finds every gap in turn. If somebody in the house works nights, or you are trying to get a toddler to nap through a bright Pakenham afternoon, all four details matter together: sealed top, side returns, centre overlap, floor-length drop. Getting three out of four gives you a room that is noticeably better and still not dark.

The other factor is the early sunrise. In midsummer the sun is up before half past five here, so an east-facing bedroom takes direct low sun at exactly the hour most people are still asleep. That is a sides-and-top problem more than a fabric problem, which is why we push returns and pelmets so hard on estate homes.

What it costs to do properly.

• Triple weave blockout curtain, $300 to $750 per window
• Lined blockout pinch pleat, $350 to $900 per window
• Fabric-covered pelmet where there is no bulkhead, $180 to $450
• Timber or MDF pelmet, $200 to $600
• Returns and overlap arm, a small addition and the best value on the quote
• Adding a blockout lining to curtains you already own, $150 to $400 per pair

A genuinely sealed bedroom window usually lands between $560 and $1,150. Full workings in the 2026 cost guide. If the room also needs daytime light control without full darkness, a blind behind the curtain gives you both settings.

A note on nurseries and children's rooms.

The same sealing rules apply, plus safety considerations around cords and chains and washability. Those are covered separately in the nursery curtains guide.

Frequently asked questions.