LDN4SQ LED Square Downlight | Lithonia Lighting

The LDN4SQ delivers a color rendering index (CRI) above 90, meaning it reproduces colors with high accuracy compared to natural daylight or incandescent sources. CRI is measured on a 0-100 scale, with higher numbers indicating better color fidelity.

In practical terms, a 90+ CRI ensures fabrics, paint, wood finishes, and food appear true to their actual hue under the fixture’s light. This is especially important in kitchens, closets, and spaces where color-critical tasks happen. Budget LED fixtures often sit in the 80-82 CRI range, which can make reds look muddy and whites appear slightly greenish.

Before connecting line voltage to the fixture, locate the small DIP switch on the side of the LED driver module inside the housing. The switch has three positions corresponding to 600, 800, and 1000 lumens. Slide the switch to your desired setting, then proceed with wiring and installation.

Once the fixture is energized and the trim is installed, the lumen setting is locked in. If you need to change it later, you’ll need to de-energize the circuit, remove the trim ring, access the housing, and adjust the switch again. For that reason, we recommend testing your preferred brightness level in a sample room before installing an entire project’s worth of fixtures.

Yes, the LDN4SQ is compatible with most smart dimmer systems, including Lutron Caseta, Leviton Decora Smart, and similar Wi-Fi or RF-controlled dimmers that use standard phase-cut dimming technology. The fixture’s driver responds to both forward-phase and reverse-phase signals, so it works with the vast majority of residential smart switches.

Before purchasing, verify that the total wattage of all LDN4SQ fixtures on the circuit falls within your smart dimmer’s load range. Each fixture draws approximately 11 watts at full output, so a dimmer rated for 150 watts can handle up to thirteen fixtures. If you’re pairing the LDN4SQ with a Lutron Caseta system, we’ve tested smooth dimming performance down to 10% with no flicker or dropout.

For remodel installations in existing drywall ceilings, cut a 4⅛-inch square opening. The product package includes a paper template you can tape to the ceiling and trace with a pencil before cutting. Use a drywall keyhole saw or reciprocating saw to make the cut—take care to avoid joists, wiring, and plumbing behind the ceiling.

Once the hole is cut, the LDN4SQ housing pushes up into the opening and spring-loaded clips automatically grip the backside of the drywall, holding the fixture in place. The square trim ring then snaps onto the housing lip and covers the cut edge, creating a clean finished appearance with no visible fasteners.

A 50,000-hour rated life means the LED module will maintain at least 70% of its initial lumen output after 50,000 hours of continuous operation. In typical residential use—averaging three hours per day—that translates to approximately 45 years before the fixture reaches the L70 threshold.

In practice, most homeowners will never experience noticeable lumen depreciation during the time they own the home. Even in commercial settings with longer daily run times—say, ten hours per day—the LDN4SQ will deliver over thirteen years of service before output drops below the L70 mark. This long life eliminates recurring lamp replacement costs and the labor associated with relamping crews.

The LDN4SQ housing requires a minimum of 5¼ inches of clearance between the finished ceiling surface and any obstruction above, such as joists, ductwork, or structural framing. If your ceiling plenum offers less than that, the housing will not fit and you’ll need to consider an ultra-low-profile alternative.

Measure the available clearance before ordering. In retrofit scenarios where shallow ceilings are common—such as basement remodels or drop-ceiling conversions—verify clearance at multiple points along the planned fixture locations, since joists and ductwork can reduce headroom in unpredictable ways.