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Lighting Commentary

Sustainability Part 3 – How Am I Going to Make This Work?

Charles and Ray Eames, La Chaise

Imagine you are Ben Watson. The world of offices has changed and he sits atop the Herman Miller – Knoll merger. Will people return to an office? Will offices disappear completely? Can his company survive? What do you do? What products will be needed in this new world?

Watson holds a degree in visual and environmental studies from Harvard and spent years in product development and marketing for Knoll. His senior thesis explored La Chaise, the modern-classic chair with a white molded polyurethane seat and crossed wooden feet designed by Charles and Ray Eames. Like all designers, he is uniquely qualified to solve a problem he had not anticipated. It is in fact why we have designers. Designers solve problems that most people find confounding.

Like Watson and office furniture, lighting is now shifting. An increased desire for sustainability is leading to pushback of disposable luminaires. Renewables are overshadowing replacements. As a result, a complete rethinking of how we illuminate our spaces must now occur.

In the first part of this sustainability blog-triumvirate I indicated that fewer decorative lighting products would be employed in the future. In part two, I talked about the ways in which the industry must step up to meet the needs of the new sustainable consumer. Figuring out how to put it all together in a way that is aesthetically pleasing now falls to the designer.

When to Feature Decorative Lighting

If we are going to use less decorative lighting and most of the decorative lighting on the market will deliver fewer lumens, not because of the substandard capabilities of LED, but because of the forms in which the LED is placed, then we must choose wisely. A five light chandelier equipped with five, 60 watt incandescent light bulbs delivered about 4000 lumens of light. Because the diffusers were large enough to cover a medium-based lamp, almost all of that light was usable. 4000 lumens of light was plenty for most dining rooms, dinettes and bedrooms. While many of the newer LED luminaires might promise 4000 lumens, it may be delivered in a slightly different way. It might be more directional, it might be concentrated in an oblique pattern or, it may obscured or simply used as an aesthetic element rather than a functional lighting machine. To make this work, the designer must be more comfortable with the overall lumen demands of a room or space.

With that in mind, the functional lighting must deliver almost all of the needed light in the space. Any illumination provided by the decorative product will likely be icing.

There are guidelines that help us determine optimal light levels for every room in a residence. There are also easy ways to use this information. Below is a chart that provides optimal light levels for each space.

Area / TaskDesired Illuminance Level in Footcandles (Fc)
Hallway/Passageway5-10
Conversation Area / Entertaining5-20
Dining10-20
Reading (General)20-50
Bathroom / Grooming20-50
Laundry / Ironing20-50
Kitchen (General)20-50
Kitchen (Work Areas)50-100
Reading (difficult) Study / Hobby / Music50-100
Hand Sewing / Detail Hobby100-200

To use this information, simple calculate the room or space area (Length multiplied by width) and multiply it by the desired footcandle level. The result will provide the needed lumens.

Length x width x footcandle = minimum Lumens needed for the room

Let’s assume we have a 12’-0” x 12’-0” dining room. 12 x 12 = 144 x 10 = 1440. 12 x 12 x 20 = 2880. That means the minimum amount of light should produce between 1440 and 2880 lumens.

When you think about that 5-light chandelier at 4000 lumens, or even a classic Williamsburg-type 10-light chandelier with candelabra lamps (280 lumens x 10 = 2800 total lumens.) incandescent provided very usable amounts of light for a dining room. We now need to think about it, just a bit more.

A New Way Forward

Let’s put the chandelier on the back-burner initially. The important thing to understand is decorative lighting will not and likely cannot provide all of the needed light. It should represent a declining percentage of the total demand for a sustainable future. How might that be delivered? Consider this.

Recessed cans around the perimeter might be a starting point. On a smaller room like this, think about one in each corner. Using a typical LED version, 650 lumens each will be provided. Now, consider an illuminated tray, or perhaps cove lighting. Somewhere between 48 linear feet of LED Tape (cove,) or as little as 32 linear feet (tray.) There are many LED Tape options. I’ll use an average of 200 lumens per foot. That will deliver between 6400 (tray) and 9600 (cove) lumens. Keep in mind, this is indirect light, so that might seem high, but will be very usable and acceptable. With the corner lights and tray lighting, the needed amount is met. These are sustainable choices and will have no impact on the style choice of the room, modern or tradition or anything in-between.

Decorative lighting can now be added. The amount of light provided will be unimportant. These then become aesthetic choices. Include them, or don’t. They will add light, but will not bear the bulk of the illuminance burden.

Now, simply repeat this with the other lighting in the other areas of the house.

LED lighting is different light, but it has also allowed designers and engineers to create more interesting and better luminaires. That means as design practitioners, we will need to take a few added steps to insure quality lighting is delivered in the space. As more sustainable environments are demanded, this added step will be needed.

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