by Jeffrey Dross

Exploring LED Tape light run length, light quantity, and color temperature

In the last post I talked about the ubiquity of LED Tape and where it can be placed. Three key areas remain. First, how much light do I need? What lumen output should I select when considering the addition of LED Tape? Then, maximum run lengths must be regarded. These will be a factor when designing the system. Lastly, we’ll review color temperature recommendations. With the four areas covered, selection, design, specifying and implementing LED Tape into an interior design is easy…or can be easy, once you’ve done it a few times!

Output

Like a Ford Model “T” black-only color choice, when LED Tape was first introduced, there was a single light output available. A quick glance at almost every major manufacturer’s catalog today will result in a huge variety of lumen output options. That is in response to the varied applications in which LED Tape has found itself. Toekicks, above cabinets, inside cabinets, coves, tray ceilings, drop ceilings and under countertops. Each of these spots need different light. In addition, surrounding surface colors will impact output, so more light should be used with darker colors.

When looking at an LED Tape product catalog. You will find a key piece of information, “Lumens per Foot.” This will range from 100 to about 1000 lumens/foot. You can assume cost will be commensurate with output, so it is important for lighting professional to select the item that delivers the right amount of light; but what is right?

Here are few guidelines based on use. Remember darker surrounding colors should use the numbers at the high end of the range. Light on taller ceiling might need a bit more light than an older 8’-0” ceiling height. If the distance from the top of the cabinet to the ceiling is short, use less light, if the cabinet is small, minimal lighting is needed inside. These are lumen ranges for a reason. Categories are intentionally vague to invite design professional input.

Application	Lumens per Foot Range
Mood lighting / Light Used as a Background	100 to 300
Accent lighting / For Added Aesthetics	150 to 500
Task Lighting – Close	275 to 500
Task Lighting – Far Away (light location)	350 to 700
Indirect Lighting	375 to 575
Cove Lighting	180 to 500
Principle Lighting in a Room	400 to 1000
As a Replacement for Linear Fluorescent Lamping	500 to 950
Kitchen Under-Cabinet Lighting	175 to 550*

*see comments regarding kitchen under-cabinet use in the previous post

Remember, lighting is cumulative, if you cannot find 800 lumens per foot tape at your favorite retailer or from a preferred brand, use two rows of 400 and you will get the same output. Two low-lumen output lengths might also be less expensive than a single length that delivers twice the light. Consider all options.

When designing with light, as with any other aesthetic element, extra attention might be desired in select areas. Feel free to veer from the suggestions. Like with anything, understand the guidelines and alter them with knowing intent.

Diffusers – The use of diffusers over LED Tape will reduce the lumen output. In some places, it is necessary, such as in-wall, drywall deep designs. That should be factored into the design. Some clients prefer the clean, non-mechanical looks of a channel and diffuser even in under-cabinet or above cabinet applications, usually for cleaning purposes. When not required, consider eliminating diffusers. Better output will result.

Run Lengths

The other piece of information you will find next to every manufacturer’s product is “Maximum Run Length.” You will typically find an inverse correlation between “Lumens per Foot” and “Maximum Run Length.” Essentially, you can run tape farther with less lumen output. If large amounts of light are needed, the runs will be shorter. You will see maximums of as little as 10’-0” and I have seen some specifications that reach up to 65’-0”, but usually 32’-0” is the limit.

Maximum run lengths comprise of the actual lighted length of LED Tape, so if the start of the tape is 5’-0” from the power and wire is needed to jump from one cabinet section to another requiring 9’-0” of interconnection wire, those are NOT counted into the maximum run length.

When laying out a LED Tape system, clever power supply placement can maximize these limitations. For example, if a 10’-0” square tray ceiling is to be illuminated and 20’-0” run length maximums are selected, place the power supply in a corner and run the first 20’-0” length in one direction and the second run in the opposite direction. This will not be a contiguous 40’-0” run, but it will give the exact same appearance. A small amount of pre-planning will eliminate hours of rework or multiple power supplies.

Color

If you read this blog regularly, or if you have heard me speak at any point in the last decade, you know I regard light color in residential applications very narrowly. I believe lighting should be either 2700K or 3000K. Warmer finishes used in the home, such as beige walls, wood cabinets and earth-tone carpets will always look better with 2700K light.

Homes that are “cooler” with lots of white, black, blues, greys and stainless steel will find those colors best represented using 3000K. The ONLY time I suggest or use anything different is if a client has a display case with collectable crystal or sterling silver. 4000K adds the necessary blue to allow these object to “sing!” Other designers disagree and employ a wider variety of color. Many of their opinions are well placed, but I still maintain the “A” or “B” decision is all that is required. It doesn’t have to be complicated.

While most reputable LED Tape uses diodes with a Color Rendering Index (CRI) of 90 and above, be sure to check the CRI is in this range. CRI is an important indicator of how well the colors in a room will look.

Another frequently asked question regarding color is, “Can I mix color temperatures in a room/home?” My response is always the same. “Do you mix colors in a room?”

If you’ve ever painted a room with two or three different shades, you did that for a reason. A deliberate decision was made to use light blue paint on the wall, mid-range blue tiles on the floor and deep indigo on the window dressing. Apply the same logic to light. If there is a reason for 3000K light in a tray ceiling and 2700K at the counters, then mix away. Do not, however simply scatter varying colors of light pell-mell across the room. This is the design equivalent of five different fluorescent tubes in the ceiling troffers of an old office.

A Few More Things

As we have seen change in LED Tape over the last ten years, change continues today. Manufacturers introduce new “bells and whistles” every month and the popularity of the product has pushed vendors to change, update and rethink almost everything about it. Following are a few things you can buy now or will see on the horizon.

COB Tape – Some consumers have objected to the dot of LED reflecting in polished granite surfaces. One solution is placing the LED Tape inside an extrusion and adding an etched acrylic cover or diffuser. While this does ameliorate the bright spot of light, it also reduces the lumen output, sometimes considerably. Chip-on-Board (COB) Tape delivers a continuous strip of light, rather than individual dots. Some brands are offering it today. It is priced higher than traditional LED Tape, but the output is good and the run lengths are likewise acceptable. This could be a nice option when faced with this particular client pushback.

Dimming – Most every manufacturer now offers dimmable LED Tape. Remember, dimming requires a power supply with dimming capabilities and like all LED, the dimmer and the power supply MUST be compatible. Always consult the tape manufacturer’s dimmer recommendation. Before that, ask whether dimming is even required. With the wide range of lumen output, dimming might take a great lighting design and ruin the results as output is constantly in flux.

120V LED Tape – We are seeing more and more “line-voltage” LED. The elimination of a power supply is very enticing. Simply connecting the electrical wires directly to the LED is an intoxicating draw. Some are good. Many have problems. Caution should be used if 120V LED Tape is considered. The same cautions you would attribute to 120V LED bath lighting or chandeliers.

120V LED are substantially more vulnerable to flicker. This can be eliminated, but it required additional circuitry that might reduce the monetary savings achieved by removing the power supply. Ask about flicker rates or percentages, especially if clients are physiologically vulnerable to flicker.
120V LED are more difficult to dim. Again, this can be solved, but the added circuitry means more money. If dimming is necessary, be sure to investigate the approved dimmers and other requirements.
LED Life – Most 120V LED do not last as long as low-voltage LED. The functional light provided by LED Tape could easily overlap multiple room remodels. Low-life cycle LED might not be the best option in these applications.

What started as a simple four part answer turned into a two-post response. It might sound complicated, but it isn’t. Once one systems is installed, it becomes much more intuitive. Trust me.

More information available here