Smart lighting specialist Lutron launches super-small downlights

Lutron’s Ketra division recently took the wraps off a pair of stunning architectural lighting products—the Ketra D2 and Rania D2 LED downlights—during an event at its design facility in Austin, TX. I was there for the unveiling and suggest that anyone looking to remodel or build a new home should consider these smart luminaires that work with Lutron’s HomeWorks and Athena (for commercial lighting) control platforms.

Shipping in September, these new downlights see Ketra following the “quiet ceiling” room design trend of installing ceiling lights that are barely noticeable by virtue of being so small. Where the typical ceiling can measures 5- or 6 inches in diameter to accommodate something like a BR30 incandescent or LED bulb, the Ketra D2 and Rania D2 peek through just 2-inch holes in the ceiling.

This story is part of TechHive’s in-depth coverage of the best smart lighting.

Let’s discuss the Ketra D2, first. Despite its lilliputian dimensions, Ketra promises its Ketra D2 makes no compromises in performance or flexibility, with a wide variety of focusing lenses and mechanical fine tunings available to wash, flood, or pinpoint optically pure (as in non-color-refracting) light where it’s wanted.

Lutron

Vying to be the world’s most exacting and flexible full-spectrum light source, the Ketra D2’s dome lens-topped emitter blends the output of red, green, blue, and white LEDs to mimic the color temperature and intensity of any natural light source, from cloudless afternoon daylight to the flickering flame of a single candle. The Art Institute of Chicago uses Ketra’s color-tunable luminaires to present its exhibits.

Such precision requires more than just a bulb, of course, but the processing power is housed in a slim box that’s suspended between the ceiling joists, out of sight on the other side of the ceiling. Inside, a microprocessor-based Color Lock “closed loop” controller measures the LEDs’ output and makes adjustments 360 times each second to maintain a “like new” set of performance parameters.

Ketra co-founder and COO Horace Ho told me that “the company founders are all seasoned engineers from Austin semiconductor chip companies. We didn’t come into this with lighting knowledge per se, but to solve the problem of inconsistencies in the manufacturing and performance of LEDs.”

On a tour of Ketra’s Austin factory, I got to see how the company runs 100 hours of burn-in and quality-control measurements on each and every bulb before the product is packed to go.

Jonathan Takiff/Foundry

For rooms where color tuning is not as critical, Lutron is introducing a new-to-North America brand, Rania, and the Rania D2. To the casual observer it’s visually the Ketra D2’s twin, and it will be available with most of the same trims and colors. It will likewise be wirelessly controllable with the same Lutron platform, app, switches, and third-party control systems.

But the Rania D2 has fewer features and uses three LEDs classified as white to produce its range of color temperatures. Where the Ketra D2 is a full-spectrum luminaire that can produce white light with color temperatures between 1,400 Kelvin to 10,000K—a range the company has dubbed “Candlelight to Artic Sky,” the Rania D2’s range is slightly more limited: 1,800- to 5,550K, or “Incandescent to Midday Sun.” The Rania can’t match the Ketra D2’s ability to dim to just one candela of luminosity, either.

As I hinted up top, neither of these fixtures will be cheap. A single Ketra D2 fixture lists for $850 (in flanged-fixed form) to $950 (flanged adjustable). A Rania D2 downlight, meanwhile, will set you back between $625 and $725.

Correction, June 3, 2024: We mis-identified Ketra’s co-founder and COO. His name is Horace Ho, not Howard Ho. We regret the error.