The Dark Side of Poor Lighting

March 24, 2014
Improve IEQ with quality illumination.

Eye strain, headaches, low mood, poor concentration, absenteeism, and job dissatisfaction – even a few minutes working under the wrong lighting can kill productivity.

Proper lighting is a cornerstone of indoor environmental quality. It encourages better learning in students, increased purchases in retail settings, faster healing in patients, and higher performance levels in workers.

You can easily keep occupants energetic in well-lit spaces without sacrificing your utility bill. Improve the quality of lighting by focusing on personalized controls and glare reduction.

A Glaring Problem

A Library Shines a Light on the Classics


You don’t need to squint to flip through the stories of Huck Finn or Pippi Longstocking in this library. Natural light floods the stacks of the Valley Hi/North Laguna Library, located near Sacramento, CA.

Daylighting is an invaluable component of a library environment. It creates an inviting atmosphere, reduces eye strain in readers, encourages study habits, and provides illumination for book shelves. Guests are also more likely to linger in the library if they find it visually comfortable.

To maximize the building’s design, a daylighting analysis was conducted in order to optimize site orientation. The modeling led to three key features:

  • The roof of the northern facade is raised to provide diffused light (seen in the main reading room above).
  • A southwest-facing clerestory provides additional daylighting to interior spaces.
  • Sunshine is controlled with horizontal and vertical sunscreens on the southern facade.

By tilting the roof, the southern angle is also ideally situated for photovoltaics. Building integrated photovoltatics, which are applied directly to the standing seam roof, can supply up to 12% of needed energy. The library opened in 2009 and earned LEED Gold for New Construction.

Information courtesy of Noll & Tam Architects and Green Building Services

Consider how the workplace has changed in the past decade. Collaborative trends encourage employees to have dynamic interactions, not remain stationary and isolated in a cubicle. Occupants need comfortable lighting so they can switch between work modes and devices wherever they are at in the building.

“Lighting plays such an integral part in collaborative spaces,” observes Jennifer Woofter, president of Strategic Sustainability Consulting. “When you look at the latest trends in urban office design, they often have very different lighting configurations than your standard corporate interior. That’s done intentionally to set the tone and maximize interaction.”

Time can also render lighting choices obsolete. Your interior layout will likely change long before lamps burn out or fixtures need to be replaced. When the workplace evolves but the lighting remains static, occupants will suffer from the disparity.

“Companies will rearrange their office but never touch the lighting. Fixtures that were originally positioned over workstations are now shining on the aisles, making what was once appropriate lighting all wrong,” explains Richard Manning, principal with Green Building Services, a sustainability consulting firm.

No matter the cause, inappropriate lighting isn’t just a waste of energy. It contributes to low or high contrasts, glare, poor color rendering, and inadequate distribution, notes Mark Havira, director of national accounts with Efficient Lighting Consultants. When occupants are distracted and frustrated, their productivity and job satisfaction substantially decreases.

Poor illumination also detracts from workplace safety. If people can’t properly see what they are doing, accidents and mistakes are more likely to occur, says Havira. Could a customer see the water spill on the floor to avoid a slip? Can a warehouse worker identify an accident waiting to happen? Did a librarian grab the wrong book because she couldn’t easily read the call numbers?

For example, abundant natural light can create areas of high contrast. If workers are unable to distinguish the faces of approaching guests, it could cause a security risk as their ability to recognize threatening behavior is delayed.

Beyond the functional considerations for visibility, lighting is also psychological. “It plays a huge factor in how a person perceives the workplace,” says Woofter. Studies have shown that happier workers are more industrious, their impression of the company is higher, and they have lower absenteeism or turnover rates. The right fixtures can even foster creatvity, boost morale, and encourage communication. A little mood lighting is good for the bottom line.

Shine a Light on Complaints
The Illuminating Engineering Society, OSHA, and ASHRAE outline minimal standards for lumens per square foot, but these best practices largely focus on energy efficiency and safety. How can you tell if your lighting isn’t meeting the needs of your occupants? Simply ask.

A simple walkthrough of your facility can reveal lighting disparities. Look for tape over occupancy sensors, personal lamps brought in from home, lights that are never turned on or have their bulbs removed, and unused task lights, Havira recommends. These are all indications that employees aren’t satisfied with the lighting status quo.

If you’ve ever conducted a thermal comfort survey, try adapting it for lighting quality. A simple feedback form can help identify your worst offending problems. You may find that only one area of the building is suffering from undesirable lighting. You could save significant time and money if you can target one floor or row of offices rather than a mass relamping.

You can also use a standard light meter to review lumen levels, suggests Manning. Take multiple readings throughout the day, particularly if there’s natural light, so you capture the full spectrum of light activity in the space.

While a light meter is a valuable tool, remember that it doesn’t measure color rendering index, cautions Havira. Understanding a fixture’s footcandles is only one piece of the lighting quality puzzle. A light meter alone can’t tell you if the CRI is appropriate for the space or the tasks occurring in it. Havira worked with a company that tried increasing the footcandles in a retail setting. The resulting raise in CRI, however, cast a purple tinge in the space that was ultimately deemed unsuitable.

“Sometimes the quality of lighting has nothing to do with footcandles and everything to do with the perception about how bright a space is,” Manning stresses. “For example, lighting a ceiling can make a space feel brighter, even if you haven’t adjusted the footcandles shining on people’s desks.”

Lighting should be tailored for the types of activities that will occur in a space, says Woofter. Don’t assume the lighting needs for a cluster of workstations will transfer to a private office. Individual task lighting, for example, doesn’t make sense in a boardroom if everyone is sitting around the same table.

Lighting should also set the tone for a space. “You may want a conversational lighting atmosphere for meeting rooms, which is usually created with soft or yellow lights. You might use standup torchieres to make the setting more intimate rather than overhead fluorescents,” Woofter explains. PageBreak

6 Bright Ideas for Retrofits
If you find your lighting quality is insufficient, there are a number of retrofits that can address occupant satisfaction. Consider these quick fixes:

1) Personal Controls
Make tenants happy by giving them some control over their space. The more choices occupants have to customize their lighting, the more likely they will find a happy balance in their space. And optimized work environments should yield more productive employees and fewer complaints, adds Woofter.

Occupancy sensors are great for saving energy, but remember they don’t address light quality. Dimming is one of the simplest ways to immediately improve lighting comfort. Rather than a choice of on or off, an occupant can gradually transition light levels to the task at hand, says Manning.

Not every fixture is compatible with dimming, so you may need to upgrade ballasts or put in new wall controls. If you’re considering LEDs, many newer models have dimming capabilities standard on them, says Havira.

2) Daylight Coordination

Illuminating BUILDINGS Magazine

Even though we share similar job responsibilities, our workspaces at BUILDINGS magazine perfectly demonstrate just how individualized lighting preferences can be.

Each 10x8 private office is equipped with an overhead T5 linear fluorescent (3500K) and a T8 fluorescent task light placed underneath overhead storage. A motion-based occupancy sensor is located on the wall immediately inside the doorway.

Senior Editor Jennie Morton Preference: Window

I love the natural light in my office. The high-set windows rarely cause glare and I hardly ever lower the blinds. Because I’m prone to migraines, I avoid using the fluorescent lighting. With spring showers around the corner, however, I’m looking to add a table lamp for those dark and stormy days when my precious daylighting disappears!  

E-Content Editor Samantha NissenPreference: Task lighting

Overhead fluorescent lighting makes my office feel sterile and drains my energy throughout the day. I use only my task lighting because it feels homey and is less abrasive. I definitely notice a difference in my productivity. I do admit I need to be more mindful of turning off all of my lamps before long meetings and over lunch hours!

Assistant Editor Chris CurtlandPreference: Overhead fluorescent

I’m a go-with-the-flow guy, so I appreciate that the overhead light automatically clicks on when I walk in every morning. Whether working at a computer or on a piece of paper, all I need is a bright space. The fact that one is ready for me as soon as I arrive is good enough for me.

Numerous studies have shown that daylight is the optimal source of illumination. Whether you have a glass curtainwall, large windows, or skylights, coordinate your existing daylighting sources with electrical fixtures so they don’t compete.

“The warm cast of an incandescent may be desirable, but it could also fight with the cool tones of daylighting throughout the day. If the sun goes behind a cloud, for example, occupants may be distracted by the change in light color within their workspace,” Manning explains. “Try using cool lighting near windows.”

Windowless spaces can also benefit from cool lighting because the blueish cast can mimic sunlight. People will stop making jokes about working in a dungeon or cave (unless, of course, that’s what they prefer).

You can also rearrange your space so more people have access to daylight. If the main population of your workers doesn’t have exposure to natural light, your business efficiency could be suffering.

“Traditionally, executive and managerial offices are located around the perimeters and common areas grouped in the center,” explains Woofter. “Now companies are trying to ensure daylight equality by positioning common workspaces near windows and moving specific offices or meeting spaces into the interior.”

This strategy is already rewarded in many green building certifications because of the human health benefits, particularly LEED and Green Globes. Let those enviable corner offices with the beautiful windows become available to workers of any rank.

3) Window Treatments
Access to natural views is an attractive feature for any building, but daylight has its caveats. While windows can let in bountiful streams of light, they can also bring in unwanted glare and solar heat gain.

“Companies need to be mindful if they’re going to position people in workspaces directly adjacent to windows,” cautions Woofter. “Glazing can alleviate these complications. Thermal film on south-facing windows, for example, will still let the light through while bouncing off the heat.”

If you have a new construction project, you can use daylight modeling to capitalize on orientation (see the example of the Valley Hi Library). Predictive modeling shows the path of sunlight throughout the day, Manning explains. You can anticipate heat and glare with overhangs, tinting, light shelves, or other exterior shading devices.

For multistory buildings, tailor your glazing strategy on a floor-by-floor basis.

“You can use vision glazing on the ground floor with shades, for example, but those above may have a modest amount of daylight glazing so light penetrates deeply,” says Manning.

Sometimes a standard blind is better than no glare control at all. If you’re worried about occupant preferences overriding energy measures, there are automated systems that will respond to daylight cues.

4) Standardize Fixtures
Ever walk into a space and notice mismatched lights? The discrepancy isn’t just distracting for those who look up at the ceiling – the patches of different light can result in poor lighting for those working below.

“I’ll go into a facility and routinely find a group of inconsistent light fixtures. Some will have a blue cast and others are yellow. This usually happens because bulbs have been individually replaced over the years with whatever is on hand,” Manning recounts. “Make sure to standardize the color temperature of the lighting when you relamp. Otherwise you could be using bulbs that weren’t designed for the space.”

If you are satisfied with a lamp’s output and CRI yet there are still occupant complaints, try addressing its cast. You can add reflectors to standard 2x4 fixtures to improve spread and distribution, suggests Havira.

5) Task Lighting
Never underestimate the power of the humble task light. These secondary light sources can range from a side or table lamp, torchieres, wall sconces, or track lighting. They can even include fixtures integrated directly into the workstation, such as underneath overhead storage. The key is that occupants have multiple lighting sources to choose from and they can use them at will.

Many companies also encourage a bring-your-own-lamp policy. While this places the cost of additional lighting on workers, it also affords them the greatest degree of personalization.

6) Maintenance
When was the last time you gave your lighting fixtures a good dusting? If it’s been a few years, accumulated dust and grime could be dimming the cast. A deep cleaning may be enough to make a perceptible difference.

You should also stay on top of maintenance and keep replacement records. Light quality depreciates over time and lumen output can wane long before the bulb goes out, notes Havira, particularly with metal halide and high pressure sodium.

Calculate Value on Investment
Most lighting projects are driven by energy efficiency or green building certification goals. This is the perfect opportunity to include an IEQ evaluation and improve the health and engagement of your occupants.

While the benefits of quality lighting may ride on the coattails of energy savings, there are productivity and satisfaction targets you can document as well.

For retail settings, look for sales growth. “We had a chain of convenience stores that upgraded their interior lighting from fluorescent to LEDs. This one change caused up to a 23% increase in purchases,” Havira recalls.

You can also quantify the benefits by looking at error rates, particularly for warehouse and distribution applications. Usually error rates will decline when lighting improves, Havira stresses, and the same goes for accidents.

If you want to show an improvement in occupant satisfaction, make sure you distribute a before-and-after survey. It’s imperative to have a snapshot of worker complaints before you make adjustments. You can also collaborate with your HR department to review absenteeism trends and employee turnover.

Compared to reducing your utility bill, fewer occupant complaints may seem like a secondary benefit. But if your building design can improve productivity, it’s a win-win for the entire business.

“With lighting, we often focus on the savings associated with energy efficiency. But people forget that a small gain in workplace satisfaction can dwarf any kind of utility savings,” Manning argues. “When looking at costs per square foot, you might find that a single office worker is $300 whereas energy is only around $2. Even a 1% improvement in productivity can be a greater cost savings than a 50% energy reduction.”

Jennie Morton is senior editor of BUILDINGS.

About the Author

Jennie Morton

A former BUILDINGS editor, Jennie Morton is a freelance writer specializing in commercial architecture, IoT and proptech.

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