Roller blinds: blackout, sunscreen or dim-out?

Roller blinds are cut to your window, so the decisions are the fabric, where the blind mounts and the measurements. Get those three right and the blind goes up quickly; get the width wrong and it cannot be fixed. This guide explains what the three fabric types do, which room each one suits, and how to measure.

What each fabric does

Roller blind fabrics are sold in three families, and the names describe how much light passes through the fabric itself, not around its edges.

• Blackout: a coated, fully opaque fabric that lets no light through. The room is dark except for the light gaps at the sides and bottom of the blind, which is why the mounting matters so much for a bedroom.
• Dim-out: a woven or lightly coated fabric that blocks most of the light (typically around 90 to 95 percent) and gives a soft glow in the room during the day. It gives full privacy at night and takes the heat out of the sun without making the room gloomy.
• Sunscreen: an open-weave fabric rated by its openness factor, from 1 percent to 5 percent. A 1 percent weave cuts most of the glare and heat and keeps a dim view out; a 5 percent weave keeps more of the view and lets more light through. Sunscreen gives privacy by day only: at night, with the lights on inside, the room is visible from outside.

Fabric colour changes the feel as well. A dark sunscreen gives a clearer view out and less glare; a light one reflects more heat and brightens the room. For a blackout or dim-out blind the colour is purely a styling choice, but a white back on the fabric keeps the outside of the building uniform, which some condominiums require.

Which room gets which

A bedroom usually wants blackout, mounted outside the window recess so that the fabric overlaps the wall and the light gaps disappear; a dim-out works for people who prefer to wake with the light. A west-facing living room gets the afternoon sun straight in, so a 3 percent sunscreen blocks the glare and heat while keeping the view and the daylight; add a blackout or dim-out behind it (a double roller) if the room is also used for movies or an afternoon nap.

A home office needs glare control on the screen more than darkness: a 1 to 3 percent sunscreen on the window that faces the desk does that without making the room dim. In a kitchen or a bathroom choose a polyester or PVC-coated fabric that wipes clean and does not hold moisture. For a child's room, see the note on chains below.

Inside or outside mount and light gaps

An inside (recess) mount fits the blind within the window opening. It looks tidy and keeps the sill free, but the bracket and the fabric roll need depth (usually 60 to 80 mm for a standard roller) and the fabric is narrower than the roller by about 15 to 20 mm on each side, so light comes in at the edges. An outside (face) mount fixes the blind to the wall or the window frame above the opening, with the fabric overlapping the opening by 50 to 100 mm on each side, which is what makes a blackout blind dark.

Check what the blind is fixing into. Most Singapore window walls are concrete or brick, which is fine for wall plugs; an aluminium window frame can take self-tapping screws. A plasterboard false ceiling or a boxed-up curtain pelmet needs the brackets screwed into the timber or metal framing behind it, not the board. A cassette or pelmet over the roller hides the fabric roll and closes the light gap at the top.

Measuring

Use a steel tape and measure in millimetres. For an inside mount, measure the width of the opening at the top, the middle and the bottom, and use the smallest figure; measure the drop (height) at the left, the centre and the right and use the smallest. The supplier takes the deduction for the brackets, so give the opening size and say that it is an inside mount. Check the recess depth for the bracket as well.

For an outside mount, measure the opening and add the overlap you want on each side (50 to 100 mm for a blackout) and above (50 to 100 mm, more if a pelmet will cover the roll); give the finished blind size and say that it is an outside mount. If the window is a casement that opens inward, or has a handle or a lock that stands proud of the frame, measure how far it projects and choose an outside mount that clears it, or the fabric will catch on the handle every time the blind comes down.

• Measure every window separately even when they look identical; a 10 mm difference matters for an inside mount.
• Write the width first, then the drop, and say inside or outside mount on every line.
• Note which way the window opens, where the handle is and whether an air-conditioner trunking or a curtain rail is in the way.

Chain side, motorised and child safety

A chain-operated roller has its chain on the left or the right; choose the side away from the wall or the furniture so you can reach it, and choose the same side for blinds that sit next to each other. The chain length is usually about two-thirds of the drop; a longer chain is easier to reach over a sofa or a desk. Chains must be fixed to the wall with the supplied tensioner or cord tidy, especially in a room used by small children, so that no loop hangs free and the loop stays well out of a child's reach.

Motorised blinds remove the chain altogether. Battery motors recharge from a USB cable (typically every few months, depending on use) and need no wiring, which makes them the easy retrofit; wired motors need a power point near the top of the window planned at renovation time. Both can be grouped on a remote and, with a hub, on an app or a voice assistant. A heavy blackout fabric on a wide window is the strongest case for a motor, since the roll gets heavy to pull by chain.