Curtain lights are built from a single horizontal top cable with vertical LED drops hanging from it at regular intervals. That one structural difference is what sets them apart from every other decorative lighting format: they light a surface rather than a line. Hung inside a window they turn plain glass into a wall of light; stretched along a balcony rail or a house front they cover an area that no single run of lighting can match. Three decisions settle almost everything else — the size, the IP rating and the colour temperature.
The top cable carries both the current and the weight, so it fixes the width of the display. Drops hang from it every 10 to 30 centimetres in most sets, and the diodes along each drop sit at 5 to 10 centimetre intervals. Closer spacing gives a denser, more solid sheet of light; wider spacing gives an airier, more restrained effect that suits a smaller room.
There are two ways of building the drops. Micro LEDs on fine, bendable copper wire all but disappear, so the points of light look as though they are floating — the right choice behind glass and indoors. Diodes on conventional PVC or rubber cable are more visible but stand up far better to wind, frost and damp, which is what you want outside.
Every drop is the same length and the bottom edge runs straight. This is the most adaptable version: at a window, behind a bed, as a photo backdrop, or as a soft divider in an open-plan room. Common sizes are 2 × 2 m and 3 × 3 m.
The drops vary in length, usually between 30 and 70 centimetres, which produces the familiar uneven lower edge. This format is designed to run along an eave, a fascia board or a railing, so it is far wider than it is deep — 3 × 0.5 m, 5 × 0.6 m and 10 × 0.6 m are typical. It looks restless at a window and excellent along a roofline.
In a net the diodes form an even grid instead of hanging drops. A net holds its shape, so it lies flat over a hedge, a tree trunk, a low wall or a ceiling. If you need a rectangle covered evenly, a net does it more precisely than a curtain will.
Stars, snowflakes, baubles or small shades sit on the drops instead of bare diodes. They glow more softly because the material diffuses the light, but they read as decoration during the day when switched off — which matters in a shop window and in a child's bedroom.
Width follows the mounting position; drop length follows how much of the surface you want covered. A practical rule: measure the window opening including the frame and add about fifteen centimetres. A curtain that hangs with a little slack falls better than one pulled taut.
| Size (width × drop) | Suits |
|---|---|
| 1 × 2 m | narrow window, patio door, mirror, alcove wall |
| 2 × 1.5 m | standard bedroom window, shelving, headboard |
| 2 × 2 m | wide window, photo backdrop, corner of a living room |
| 3 × 2 m and 3 × 3 m | patio doors, a full wall, wedding and event backdrops |
| 3 × 5 m, 3 × 6 m | house frontage, tall shop windows, stairwells |
| 10 × 0.5 m (icicle) | eaves, fascia, balcony and terrace railings |
On a house front, resist the temptation to cover everything with one very large curtain. Several smaller ones hung side by side and linked together are safer to fit and much easier to take down after the season.
A diode count means nothing until you set it against the size. A 3 × 3 m curtain with 300 LEDs works out at roughly ten drops of thirty points each — clearly visible, but open. The same 300 diodes on a 2 × 2 m curtain read as noticeably denser.
| Size | LED count | Character |
|---|---|---|
| 2 × 1.5 m | about 150–200 | delicate, individual points |
| 2 × 2 m | about 200–300 | balanced, good indoors |
| 3 × 3 m | about 300 | open, still reads from the street |
| 3 × 3 m | 600 and above | a solid sheet of light |
The type of diode matters as much as the count. Micro LEDs give fine, sparkling points; larger standard LEDs are brighter and push through a window pane better when the display is meant to be seen from outside.
This is the specification not to economise on, because it decides whether the display survives a wet November. The rating that counts is the one on the weakest part of the system — usually not the cable but the transformer and the connectors.
| Rating | Protects against | Suitable for |
|---|---|---|
| IP20 | no water protection | dry interiors only |
| IP44 | splashing from any direction | balcony, covered terrace, outside face of a window |
| IP65 | water jets | house walls, gardens, fully exposed positions |
| IP67 / IP68 | short and prolonged immersion | professional and year-round installations |
If a set hangs indoors but rests against glass that gathers condensation in winter, IP44 is the safer choice over IP20.
Mains sets are the answer for large curtains and for anything left outside through the season. The lights themselves run on low voltage — 24 V and 31 V are the usual figures — with a transformer just behind the plug stepping the supply down. The lead is often only about 1.5 m, so plan a socket close to the mounting point or add an extension of a matching IP rating.
Battery sets, generally three AA cells, free you from the socket and let you hang a curtain where there is no supply at all: a marquee, an exhibition stand, a display case. The trade-off is run time, which is why battery models almost always include a timer.
USB versions suit a desk, a shelf or a power bank. Solar curtains charge a small battery during the day and switch on at dusk — genuinely useful on a fence or in a garden, though a short, overcast December day cuts the run time considerably.
Warm white at roughly 2600–2700 K is the closest match to old filament lamps and the safe indoor choice, sitting well against wood, textiles and warm wall colours. Extra-warm tones around 1900–2400 K look distinctly amber and read as nostalgic rather than festive.
Cool white at about 6000–6500 K carries a blue cast and looks its best against snow and on modern grey render or brick. Dual-colour sets pair a steady warm white with cool white flashes, producing a frost or falling-snow effect. Multicolour RGB curtains let you pick a colour or run smooth transitions — popular in shops and hospitality, harder to live with in a sitting room night after night.
Most curtain lights ship with a controller offering eight programmes. The standard set is steady on, slow fade up and down, waves, sequential, chasing, slow glow, twinkle or flash, and a combination mode. The memory function stores the last programme you chose, so the set comes back on exactly as it was rather than resetting to the first mode every time it is unplugged.
Timers usually run a 6 hours on, 18 hours off cycle, restarting at the same clock time each day from the moment you first switch on. Turn a set on at four in the afternoon and it will light from four until ten for the rest of the season. A remote — infrared on most sets, radio on a few — earns its keep whenever the controller ends up out of reach after fitting, such as an upstairs window or high on a wall.
Connectable systems carry a male connector at one end and a female at the other, so lengths chain one after another and run from a single socket. Low-voltage ranges commonly allow up to twenty sets and several dozen metres in total. Treat the manufacturer's maximum as a hard limit — go past it and brightness drops away at the far end of the run, or the transformer is pushed into overload.
On these systems the supply lead with its transformer is bought separately, and the first set will not light on its own. That single detail accounts for most first-night disappointments. Cross connectors let you branch the run as well, so several curtains can be built up into one continuous lit surface.
At a window the simplest route is a curtain pole or clamp brackets on the frame. Suction hooks work on the glass itself; self-adhesive clips or small tacks driven in beside the cable — never through it — work on the frame. On a wall, adhesive hooks at 30 to 50 centimetre intervals do the job, as does a fine line strung between two fixings with the curtain hanging from it.
On balcony and terrace railings, cable ties are the most reliable fixing, closed around the top cable rather than around the drops. On a wall outside, route the cable clear of sharp flashing edges and keep the transformer under cover with the plug pointing down. Coil and secure any spare lead: a loop flapping in the wind destroys connections faster than frost ever will.
Decorative lighting chains and curtains fall under EN 60598-2-20, the standard covering luminaires of this type. A set intended for the European market carries CE marking and a declaration of conformity, and its materials meet the RoHS directive. Outdoors, always take the supply from a socket protected by an RCD.
Four rules worth following to the letter: do not link sets of different supply voltages, do not shorten or extend the cable yourself, do not cover the transformer, and do not coil a curtain while it is switched on. LEDs run far cooler than the filament lamps they replaced, but the controller and the power supply still need air around them.
Before each season, look over the whole cable for chafing, cracked insulation and any sign of moisture inside a connector. A damaged lead retires the set even if it still lights. Dust comes off an indoor curtain with a dry, soft cloth while it is unplugged; water and solvent cleaners will haze the shades.
At the end of the season wind the curtain onto a cardboard reel or a stiff card, laying the drops alongside each other so they cannot tangle. Avoid sharp kinks right at a diode, which is where the circuit most often breaks. Store somewhere dry and frost-free, in a box rather than a plastic bag where condensation collects, and take the cells out of a battery box first.
A decorative luminaire made of a horizontal top cable with vertical LED drops hanging from it. They light a surface — a window, a wall, a railing — rather than a single line.
Measure the opening including the frame and allow around fifteen centimetres extra. A standard bedroom window usually takes 2 × 1.5 m or 2 × 2 m; patio doors take 3 × 2 m.
Yes, if they are rated for it. IP44 is enough under cover, while a fully exposed position calls for IP65 — and that rating has to apply to the transformer and connectors too, not only the cable.
For a two-metre window, 150 to 300 diodes is the usual range. If you want the display to read clearly from the street, take the upper end or choose a set with tighter drop spacing.
Only sets described as connectable, with connectors at both ends and the same system voltage. The maximum number of sets quoted by the manufacturer is the transformer's limit, not a suggestion.
A CE-marked set is built to run for long periods, but a timer is the more sensible option: the 6 hours on, 18 hours off cycle covers the whole evening and spares both the controller and, on battery sets, the cells.
Very little. LED drops typically draw single-digit watts, and even a large wall-sized curtain only a few dozen. A timer cuts that further by keeping the display to the evening hours.
Icicles are the better fit along a railing: the short drops leave the view clear and give the wind less to catch. A flat curtain belongs on the balcony wall, or inside the doors.
Work through the decisions in this order — position, IP rating, size, then LED count and effects — and you avoid the usual mistake of buying a handsome set that cannot go where it was meant to. If what you actually want is a single line of light strung over a terrace or across a garden rather than a lit surface, the outdoor string lights category is the one to look at.
