Blockout curtains in Pakenham.

What a blockout curtain is

Two jobs in one piece of cloth: stop the light, and stop the heat moving. The light part is straightforward, and it comes from either a dense lining machined behind a face fabric, or from a triple-weave fabric with an opaque dark yarn built into the middle of the weave. The heat part is where most blockout curtains sold in this country quietly fail, because it depends far more on how the curtain is installed than on what it is made from.

Glass is the weakest point in any wall. On a cold Cardinia night, air touching the window cools, gets heavier, sinks to the floor and drags warm room air across to replace it. That loop runs continuously and it is why a room can have curtains and still feel cold. Interrupting it means sealing the curtain at the top with a pelmet or a bent return, running it to the floor, and closing the sides against the wall. Do that and you trap a still layer of air against the glass, which is the actual insulator. Skip it and you have hung an expensive light blocker.

Fabric and lining options

• Standard cotton and polyester lining. The baseline. Adds body and improved drape, protects the face fabric from our harsh northerly and westerly summer sun, and dims a room without fully darkening it. Good for a lounge that just needs to be less bright.
• Blockout lining. A coated or dense woven lining that stops light completely. This is what a bedroom needs, and it also adds a genuine thermal layer.
• Thermal or coated lining. A blockout lining with an added coating engineered to reflect radiant heat. The best single upgrade for a west-facing room that bakes in February and freezes in July.
• Interlining, or bump. A soft flannel-like layer sandwiched between the face fabric and the lining. It is the most expensive option and it is what makes a curtain feel heavy and luxurious in the hand. Deepest drape, best warmth, best sound absorption. Worth it in a main bedroom or a formal lounge.
• Triple-weave blockout. One fabric, no separate lining, block built into the weave. Cheaper, simpler to launder because there is only one fabric with one shrinkage behaviour, and it hangs slightly flatter. Excellent value in secondary bedrooms.

Face fabric matters less than people assume once a blockout lining is behind it, which is liberating: you can choose the face fabric on colour and texture alone and let the lining do the technical work.

Where blockout suits

Bedrooms first, always. Melbourne south-east summer mornings are bright by 5:45am and a new estate bedroom with a large east-facing window will wake a child at dawn regardless of what time they went to bed. Then media and theatre rooms, where the enemy is reflection on a screen rather than sleep. Then any room that is uncomfortably cold in winter, which in the older township homes through Koo Wee Rup and Bunyip with single glazing is often the main lounge.

Where blockout does not belong is the living and dining areas of a bright modern home. Putting blockout everywhere is the fastest way to spend a whole budget and end up with a dark house. Those rooms are usually better in sheers alone, with the money saved spent on doing the bedrooms properly. The exception is a main bedroom, where a sheer and a blockout together on a twin track gives you soft daylight, night privacy and full darkness from the same window.

How we measure and hang them

A blockout is measured to seal, not just to cover. The track runs 150mm to 250mm past the glass at each side, with a return at each end so the curtain turns back and finishes against the wall. The drop goes floor to ceiling wherever the ceiling allows, with a hem clearance of 10mm to 15mm. Where there is an existing pelmet we work behind it, which is the best possible seal. Where there is not, a bent return on the track does the same job and costs less than adding a pelmet.

Weight is the other consideration. A lined and interlined curtain across a 3 metre slider is heavy, and a light-duty track will sag and start binding within a year. Those windows get a heavy-duty track, which is why the track is quoted as its own line rather than buried in the curtain price. Pinch pleat is the usual heading for a lined blockout because the pleats carry the weight well and stack tidily. S-fold also works and looks more modern, at 10 to 20 percent more.

Price and lead time

Lined pinch-pleat blockout runs $350 to $900 per window fitted in 2026. Triple-weave blockout runs $300 to $750. Add 10 to 20 percent for an S-fold heading. Tracks are separate at $90 to $220 standard, $220 to $600 heavy-duty or bay-bent, or $700 to $1,800 motorised. Lead time is 3 to 5 weeks from approval, a little longer if a patterned face fabric needs matching across a wide drop. The full breakdown, plus a worked example for a Cardinia Lakes 4-bedroom, is on the 2026 pricing page.

Caring for blockout curtains

• Do not machine wash a lined blockout. The face fabric and the lining shrink at different rates and the curtain will pucker permanently. Dry clean, or have them taken down, cleaned and re-hung.
• Triple weave is more forgiving. Many can be washed cold on a gentle cycle, but check the label, and never tumble dry a coated fabric.
• Vacuum the top of the heading and the hem every few months with the upholstery brush. Most of what makes a curtain look tired is dust, not wear.
• Do not iron a coated blockout lining. Heat will craze the coating and you will see the marks against the light forever.
• Through winter, leave a small ventilation gap at one end overnight and wipe the sills in the morning. That is the practical answer to condensation in a well-sealed estate home.
• Once a year, open them fully on a dry day and let air move through. Curtains that stay closed in a damp room are where mould starts.

Next steps

Most Pakenham homes we do end up layered: sheers through the living areas, blockout in the bedrooms, and both on a twin track in the main. Read the sheer curtains page for the other half, or alterations if your existing curtains just need lining added rather than replacing. Ready to get a number? Book a free in-home measure and we will bring the sample books, or see the areas we cover.