It depends what you want from CoeLux. For the illusion of a sun far overhead, the closest alternative is Innerscene's Virtual Sun, which also shows a sun at infinity and casts a sunbeam, from a recessed fitting of about 35 kg that needs 254 mm of ceiling depth. For a room that feels like daylight, Sunday Light, the artificial skylight we make in London, gives 34,500 lumens, more than eight times a CoeLux 45 HC, from a fitting that hangs like a chandelier with no ceiling void at all. Sky panels give the look of a sky from about $150, and if the room has roof above it, a sun tunnel brings in the real thing.
What CoeLux does best
CoeLux is the reference for the illusion of sky and sun indoors. It began as a spin-off of the University of Insubria in Italy, and its first product, the 45 HC, has been on sale since 2014. The sky is a thin transparent layer with nanoparticles dispersed through it, which reproduces the Rayleigh scattering sunlight undergoes crossing the atmosphere, so it glows a deep blue. The optics put the sun at infinity: your eyes focus far away, and the sun stays put as you walk underneath.
In the 45 HC, a 45-degree beam lands as a warm spot with defined edges, and the blue sky light tints the shadows. The range now runs from that 1.5 m² window down to the HT25 Mini, a sky 49 by 23 cm, with the 45 LC, the long LS models and the HT25 in between. What makes an artificial skylight look like real sky explains the optics in more detail.
Why CoeLux is hard to fit in a house
The large models are heavy and deep. The 45 HC weighs 300 kg and needs a space 3.8 by 2.5 by 1.2 m above the ceiling. It hangs from the structural slab on four 1.5 m threaded rods and needs an inspection hatch beside the projector. The 45 LC weighs the same 300 kg in a space 2.4 by 1.9 by 0.9 m. Few homes have a void that size, and in a flat it usually can't be added.
The smaller models are lighter but still recessed. The HT25 weighs 50 kg and needs 25 cm of depth. The LS Matte weighs 24 kg and needs 46 cm and a drop ceiling. The HT25 Mini comes in a surface-mounted version, an 18 kg box that gives 1,600 lumens.
Then there's price. CoeLux doesn't publish one. In March 2016, CE Pro reported the 45 HC at $39,000, or about $48,000 with shipping, duties and installation. In October 2026 the retailer 360Lamps listed the LS Matte at C$12,755, the HT25 from C$22,282 and the 45 HC from C$72,600, before installation. Light output is 4,100 lumens for the 45 HC, 5,900 for the HT25 and 3,300 for the LS Matte, about what a bright ceiling light gives.
The alternatives, and what you trade
Innerscene Virtual Sun
Innerscene's Virtual Sun is the only other fitting we know of with a visible sun at infinity. It uses lenses the way a VR headset does to make its sun look far away, and throws a sunbeam at 30 degrees from vertical with 2.5 degrees of spread. It weighs about 35 kg (77 lb), needs 254 mm (10 in) of ceiling depth to sit flush and gives 4,455 lumens. Innerscene says it usually goes in during new construction or a remodel, supported by a joist in a plasterboard ceiling or dropped into a grid ceiling.
Innerscene doesn't publish prices either. Jonathan Clark, who started the company, wrote in 2020 that five or six of its units cost about the same as one CoeLux 45 LC once shipping and installation are counted. Its Circadian Sky is a sky with no sun, under 10 cm deep, with a surface-mount option and up to 6,000 lumens.
Sunday Light
Sunday is a 120 cm disc that hangs from a ceiling rose like a chandelier, and its job is to fill the room with daylight-level light. The LED sits at the bottom of the arm and shines up at the sheet. The sheet scatters the bluer light and reflects the warmer light: Rayleigh scattering, the same physics as CoeLux's sky. You see a sky glow with a warm sun-like centre.
It gives 34,500 lumens, 10,000 lux at 60 cm, against 4,100 for a 45 HC. It weighs 22 kg, needs a ceiling of 240 cm or more, and any qualified electrician fits it in 1-2 hours; a solid concrete ceiling is no obstacle. On a schedule it runs cool 6000K in the morning, then warmer and dimmer through the afternoon, with a CRI of 97+. Water flows through the arm to cool the LED, which is what lets it run at full brightness all day.
Sunday Light, our indoor sunlight ceiling light, is £5,900 in the UK, $6,900 in the US and €6,900 in Europe, with free worldwide delivery. You can see one by appointment in London, New York, Palo Alto and Zurich.
Sky panels
Philips Skylight (from €499.99 at its June 2026 launch), Govee's Sky Ceiling Light ($399.99, 7,000 lumens), Lumary Skylora ($249.99, 4,000 lumens) and Nanoleaf Skylight ($149.99 for three panels on offer in October 2026) fix flat to the ceiling in place of an ordinary light. They run a daylight schedule and look like a patch of sky on the ceiling, with no sun at a distance and no beam. Artificial skylights that don't need a hole in the ceiling covers how each one fits.
A real skylight or sun tunnel
If the room sits under a roof, real daylight costs less than any of these. A VELUX Sun Tunnel carries light from a 25 or 35 cm opening in the roof down a reflective tube to the ceiling, and Solatube puts a kit at $200 to $700. It needs a hole through the roof, follows the weather and goes dark at night.
