This blackout curtains guide comes down to four things: how much light the fabric actually blocks, how well it insulates against heat and cold, how you mount it, and whether curtains or blinds suit the window. True blackout fabric blocks close to 100 per cent of light, helping you sleep better and trimming heating and cooling bills year-round.
What actually makes a curtain "blackout"?
Blackout is about the fabric, not just the colour. Genuine blackout curtains use a tightly woven or coated fabric, often with a foam or triple-weave backing, that stops light passing through the material itself.
Watch the labels closely, because "blockout", "room darkening" and "blackout" are used loosely. Room-darkening fabric dims a space but still lets a glow through, while true blackout aims for near-total darkness. If total dark is the goal, a coated or triple-weave backing is what you want.
How much light do you actually need to block?
Be honest about the room. A nursery, a shift worker's bedroom or a home theatre needs the darkest possible fabric, while a lounge or study is usually fine with room-darkening.
Remember that light leaks around the edges as much as through the fabric. A blackout curtain that stops short of the wall or ceiling will still let daylight spill in at the sides and top, so coverage and mounting matter just as much as the fabric rating you choose.
Do blackout curtains really lower power bills?
Yes, a heavy, well-fitted blackout curtain is one of the cheapest ways to insulate a window. Windows are a major source of heat loss in winter and heat gain in summer, and a dense curtain traps a layer of still air against the glass.
For the best result, mount the curtain to seal at the top with a pelmet or a snug fit, and let it reach the floor. Pairing effective window coverings with a warm bed, such as a wool-filled Woolcomfort merino wool quilt, means you can run the heater less and still stay cosy through the coldest nights.
Curtains or blinds: which should you choose?
Both can deliver blackout, so the choice comes down to the look, the window and your budget. Curtains give better insulation and softness, while blinds suit a clean, modern window and tight spaces.
Blackout roller and honeycomb blinds sit close to the glass and look tidy, but light can sneak down the sides unless you fit them inside a channel or overlap the frame generously. Many people get the best of both by layering a blackout blind under decorative curtains.
How do you mount them to kill light leaks?
Mounting is where most blackout jobs succeed or fail. To seal out light properly, follow a few simple rules:
- Go wide: extend the rod or track 15 to 20cm past the window on each side so fabric overlaps the wall.
- Go high: mount close to the ceiling to stop light spilling over the top and to make the window look taller.
- Add a pelmet or return: a boxed-in top or wrap-around bracket blocks the gap where warm air and light escape.
- Reach the floor: full-length curtains trap more air and block low, raking morning light.
Which blackout option suits which room?
The right pick depends on who uses the room and what it is for. Use this quick comparison to match the option to the job.
| Option | Best for | Light block | Insulation | Watch out for |
|---|---|---|---|---|
| Blackout curtains | Bedrooms, nurseries, living rooms | High with good coverage | Excellent | Need width and floor length to work |
| Blackout roller blind | Modern rooms, small windows, offices | High face-on, leaks at sides | Moderate | Side gaps unless channelled |
| Honeycomb (cellular) blind | Insulation-focused rooms, cold climates | Good to high | Excellent | Higher cost than a plain roller |
| Blind plus curtain layer | Master bedrooms, home theatres | Near total darkness | Excellent | More outlay and hardware |
| Portable blackout blind | Renters, travel, nurseries | Moderate to high | Low | Temporary, suits a single window |
Which type suits which person?
Renters should lean toward tension-rod curtains or portable stick-on blinds that leave no holes and move house with you. Families with young children get the most from full curtains in the nursery, where every extra minute of morning sleep counts.
Shift workers and light sleepers should invest in the layered blind-plus-curtain approach for near-total darkness. Style-focused renovators can treat curtains as a design feature, using them to soften a room and add height while still doing the practical job.
Do fabric weight and lining matter?
Weight is a good shortcut to quality. Heavier blackout fabrics generally block more light, insulate better and hang with a fuller, more luxurious drape than thin, lightweight panels.
You will also see two main constructions. Coated or foam-backed curtains have a rubberised layer bonded to the back for maximum darkness at a lower price, while triple-weave fabrics build the blackout into three layers of yarn for a softer feel and a nicer look on both sides. If the back of the curtain faces the street, triple-weave or a separate lining looks tidier from outside.
Do colour and style change the result?
With genuine blackout fabric, the backing does the blocking, so you are free to choose almost any colour on the front. Darker colours can absorb a touch more stray light and hide dust between washes, but a crisp white or soft neutral works just as well over a blackout backing.
Style-wise, floor-length curtains with generous fullness read as more considered and block light better than skimpy, flat panels. Pinch-pleat and wave headings give the fullest look, while a simple eyelet heading is the easiest to slide and the most budget-friendly.
How do you care for blackout curtains?
A little care keeps blackout fabric working and looking good for years. Always check the label first, as many coated and foam-backed fabrics are not suited to hot washing or the dryer.
- Vacuum with a brush attachment every few weeks to lift dust before it sets in.
- Cold or warm gentle machine wash for most fabrics, then hang to dry, as heat can crack the backing.
- Iron on low only if the label allows, and never press directly on a coated back.
- Spot-clean marks quickly with a damp cloth rather than soaking the whole panel.
Setting up the whole sleep environment pays off alongside good curtains. A quiet bedside light like a rechargeable battery wall sconce set with remote and dimmer lets you wind down in warm, low light without flooding a darkened room, and a fresh quilt cover or throw from a good bedding and linen range completes the restful feel.
How to measure before you buy
Measure twice and buy once. For curtains, measure the track or rod width, not the glass, and add generous overlap on each side, then decide between sill length and floor length.
For blinds, measure inside the frame for a recess fit or outside for full coverage, and go for the outside mount if blocking light is the priority. Order the widest, longest option your window and budget allow, because in blackout, extra coverage always beats a tight, leaky fit. Once the windows are handled, the wider home range has the finishing touches to make the whole room feel calm and complete.
Frequently asked questions
Do blackout curtains actually save money on energy bills?
Yes. Windows lose a lot of heat in winter and gain heat in summer, and a heavy, well-fitted blackout curtain traps a layer of still air against the glass to slow that transfer. For the biggest saving, mount the curtain high, let it reach the floor, and seal the top with a pelmet or snug fit.
What is the difference between blockout and blackout curtains?
The terms are often used interchangeably in Australia, and both aim to stop light through the fabric. In practice, check the description: true blackout uses a coated or triple-weave backing for near-total darkness, while some "room darkening" fabrics only dim the light and still let a soft glow through the weave.
Are blackout blinds or curtains better for a nursery?
For the darkest possible nursery, layer a blackout blind fitted inside the frame under full-length curtains, which blocks both the glass and the gaps at the sides. If you only pick one, choose wide, floor-length curtains mounted high and beyond the frame, as blinds alone tend to leak light down the edges.
How do you stop light leaking around blackout curtains?
Light escapes at the sides, top and bottom, not just through the fabric. Extend the track 15 to 20cm past the window on each side, mount close to the ceiling, add a pelmet or wrap-around return, and run the curtains to the floor. For blinds, use side channels or a generous outside mount over the frame.
