How Do I Install Lights Under Kitchen Cabinets?
Kevin O’Connor finds a certified lighting consultant to explain the best practice for lumens per foot
What is the recommended number of LEDs per foot for the lights under kitchen cabinets?
—Jim Seatter, via e-mail
When it comes to lighting questions, I go to Susan Arnold, a certified lighting consultant with Wolfers Lighting who has worked on more than a dozen TOH TV projects. Here’s what she has to say.
“As with many simple questions, the answer isn’t so simple. First, it’s not about counting the number of LEDs in a fixture; the light output of individual LEDs varies too much to make that practical. What you really need to know is how many lumens a fixture produces per foot. For undercabinet lighting, that number should be around 300 to 350 lumens per foot, which is enough illumination for food prep or after-meal cleanup.
“When those tasks are done, however, you’ll want to be able to dial back the light intensity. That’s the job of the LED driver. It converts alternating current to direct current, precisely regulates the voltage going into the fixture, and also determines how smoothly and how much your lights will dim. The best drivers, which run about $200, can take a fixture down to 1 percent of its rated output, without a hint of flicker.
“The other quality to look for in a fixture is a high color rendering index (CRI). This tells you how accurately the colors show up in comparison with sunlight, which has a CRI of 100. High CRI fixtures rate in the 90s. The color of the light itself—its color temperature, in kelvins (K)—is a personal choice. It ranges from the cool, bluish cast of 5000K lighting to the warmer 2700K and 2200K temperatures that most people prefer.
“The fixtures that meet these criteria are linear LED strips, such as the low-profile Kendo S (Luminii). It runs about $75 a foot. LED rope lights are much less expensive, but lack the brightness of the strips, and their unfiltered light will reflect off any shiny or polished surface, such as a stone countertop, as myriad dots of light. They’re not a good fit for kitchens. LED puck lights are brighter than ropes, but have the same reflecting problem, and don’t illuminate evenly. The linear strips, by contrast, have lenses that soften and spread the LEDs’ intense light over a wider area.”