Productivity and Green Buildings
Natural light and materials have undisputable power.
Alex Wilson -- Interior Design, 4/14/2005 12:00:00 AM
I do most of my focused writing in my home office—where I’m sitting now. I used to think that I liked to work at home because it was free from most distractions, but as I learn more about the relationship between the spaces where we work and our productivity and creativity, I’m becoming convinced that there are many other reasons. The view of filtered sunlight sparkling on dew-covered ferns outside my windows, for example, may be providing a sense of well-being or relaxation that boosts my productivity.
We have long known on an intuitive level that our work environment impacts our performance; it’s the fundamental reason company managers spend billions of dollars each year upgrading work environments, investing in better office furniture, and improving acoustics. But our understanding of this relationship has been rudimentary at best. We are now beginning to quantify the benefits of a better work environment and translate that vague intuition into measurable bottom-line benefits. The same process is occurring in classrooms, where certain features are being shown to improve learning; in hospitals, where similar features promote healing; and even in retail establishments, where particular features apparently increase sales.
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Many of the attributes of buildings that are being shown to improve human performance and productivity are also characteristics of green buildings: daylighting, views to the outdoors, improved air quality, and individual control of fresh air and comfort. Indeed, for many types of buildings, the evidence of improved productivity is—or will become—the most compelling reason to pursue a green agenda. This article examines the complex but fascinating issue of human productivity as it relates to building design. While most relevant to those involved in commercial building design, this discussion relates to anyone with a child in school or who may use hospital services at some point.
Understanding Human Productivity
Productivity can mean a lot of different things. According to Vivian Loftness, FAIA, a professor of architecture at Carnegie Mellon University in Pittsburgh, productivity has traditionally been measured primarily in blue-collar work, such as manufacturing, where it’s fairly easy to compare the inputs (for example, raw materials and labor), with the output (such as the number of widgets produced in a given period of time). In an office setting or other nonmanufacturing facility, assessing productivity is more difficult—but no less important.
William Fisk, P.E., senior staff scientist and head of the Indoor Environment Department at Lawrence Berkeley National Laboratory (LBL), prefers to use the term “performance” rather than “productivity,” as the latter more commonly refers to the economic performance of a business. “For many types of work, we don’t have good definitions or metrics for worker performance,” he told EBN.
In some respects, factors that negatively affect performance are easier to understand than factors that positively influence it. If a building makes its employees sick, or if noise creates so much distraction that workers can’t get their jobs done, those impacts on performance are fairly obvious. Most of us intuitively understand these adverse health and productivity effects, and we can measure them relatively easily. Factors that actually boost performance above a baseline are harder to understand and quantify—and that shows in the available research data. “The evidence that IEQ [indoor environmental quality] and building design and operation affect health is more extensive than the evidence that building design and operation affect productivity,” says Fisk.
We can use numerous metrics to examine the effect of buildings on productivity or performance. Some of the most important are described below, along with some relevant research.
Illness and absenteeism
The health of employees, and students in the case of schools, is one of the most important indicators of productivity—and one of the easiest to measure. “Productivity improvements are driven primarily by health,” according to green building expert Gregory Kats of Capital E, who argues that the term “health and productivity” should be used in this discussion. It stands to reason that if workers or students are absent due to illness—or if they are on-the-job but sick—productivity will drop.
In the U.S., according to Loftness, absenteeism averages about 3% of the work year. In one of the most famous studies linking green building to higher productivity, absenteeism in a new, daylit Lockheed-Martin Corporation facility was found to drop 15%. Other studies have produced similar—though not always so dramatic—findings.
Many aspects of buildings can make people sick, and, conversely, many features of green buildings can protect occupant health. One of the most obvious factors is the ventilation system. Conventional ventilation systems in commercial buildings can distribute germs and viruses throughout a building, while a well-designed displacement ventilation system (such as underfloor conditioned air supply with ceiling exhaust) eliminates such disease-causing organisms very effectively.
Fisk argues that tremendous economic savings are achievable through better ventilation systems. In the Indoor Air Quality Handbook (McGraw Hill, 1999), he shows that the annual U.S. healthcare cost for upper and lower respiratory tract infections is approximately $36 billion, and the annual lost productivity from those infections (from absenteeism and reduced productivity when on-the-job but sick) represents $34 billion. Based on results from ten studies, Fisk concludes that improved ventilation systems would reduce respiratory illness by 9–20%, which translates into 16 to 37 million fewer cases of common cold and influenza and annual economic savings of $6 to $14 billion.
Staff retention
It costs companies a great deal to hire and train new employees. If certain features make a building more satisfying or enjoyable to work in and if that improves staff retention, it stands to reason that the company will benefit from having those features in its buildings. This is an important selling point of green buildings in the real estate market. While more difficult to measure than absenteeism, staff retention can be quantified, allowing us to examine whether various building features influence how long employees remain with the company.
Bill Browning, founder of the Rocky Mountain Institute’s Green Development Services and now with Haymount, says that staff retention was one of the prime drivers of the green agenda at the Letterman Digital Arts Center being built in San Francisco’s Presidio by Lucasfilm, Ltd. The company was tired of losing highly trained digital artists to competing companies, according to Browning. The costs of job training can be “enormously high,” he says. The U.S. Air Force, for example, spends tens of thousands of dollars to train each enlistee and up to several million dollars to train a fighter pilot. When you spend a lot to train personnel, you want to do whatever you can to keep them. (Greening initiatives at Navy and Army housing over the past ten years, two of which BGI staff participated in, have been driven to a significant extent by the potential for increasing personnel retention.)
Job performance
With job performance, we get into more challenging metrics of human productivity. As noted previously, job performance with manufacturing can be measured as product output and the rate of product rejection during inspections. With most white-collar jobs, performance is more difficult to measure. Exceptions are jobs that involve repetitive tasks, such as sorting mail or processing insurance forms, for which both speed and accuracy can be assessed. Limited quantitative metrics are also often available at call centers. “In call centers,” according to Fisk, “where large groups of workers interact with the public or clients via telephone, or use computer systems to obtain or enter related information, we can use automatically collected telephone call data to assess speed—but not quality—of work.” Instead of measuring actual job performance, some productivity researchers use special simulation tests that indicate job performance.
A recent study by the Heschong Mahone Group (HMG), Windows and Offices: A Study of Office Worker Performance and the Indoor Environment (published October 2003), examined the influence of natural lighting and windows on job performance at the Sacramento Municipal Utility District (SMUD). This is one of several HMG studies, funded by the California Energy Commission (CEC), that follow-up ground-breaking studies on daylighting and productivity performed by the same group (see EBN &EBN volume="8" number="9">Vol. 8, No. 9&/EBN>). The SMUD research involved two separate investigations. One of these, the Call Center study, looked at the performance of 100 SMUD employees at a facility handling customer inquiries. SMUD continuously monitors the performance of these workers by tracking the length of calls (shorter calls indicate better performance); this performance data can then be correlated with building attributes. The second research project, the Desktop study, tracked the performance of 200 office workers at SMUD on short cognitive assessment tests conducted on their computers.
&FIGURE> Group, Inc.
Higher daylight levels were found to improve performance on some, but not all, of the cognitive assessment tests. An increase in daylight illumination from 1 to 20 footcandles improved by 13% the ability of workers to instantly recall and mentally reverse a string of numbers. But the higher daylight levels neither improved performance on visual acuity and long-term memory tests nor shortened the average call-handling time in the Call Center study. On the other hand, researchers found a significant correlation between access to outdoor views and worker performance. In the Desktop study, workers performed 10–25% better on tests when they had the best possible view as opposed to no view, and in the Call Center study workers handled calls 7–12% faster with the same parameters. Conversely, glare from windows reduced test performance by 15–21%. Positive correlations were also found between productivity and increased fresh air supply.
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The correlation between access to views and performance was the most striking result. “It was the most consistent finding we’ve found in any of our studies, Heschong told EBN. “It blows me away.”
Classroom learning
The 1999 HMG study Daylighting in Schools (see EBN &EBN volume="8" number="9">Vol. 8, No. 9&/EBN>) showed that students in classrooms with the most natural daylighting (from skylights) progressed 20% faster in math and 26% faster in reading than students in classrooms with the least natural light. In a more recent CEC-funded study, Windows and Classrooms: A Study of Student Performance and the Indoor Environment, HMG set out to see if the connections between daylighting and student performance could be replicated in a different location and with differently configured daylighting. Five hundred classrooms in 36 schools were studied in Fresno, California. Many different building attributes were examined, including the same “daylight codes” that were used in the earlier study to distinguish different degrees of daylighting—but in this case, none of the daylighting was provided by skylights; all was from windows. With this study, a positive correlation between the extent of daylighting and student performance was not found; in fact, more daylighting worsened student performance.
However, many statistically relevant findings in the study demonstrated a causal relationship between window characteristics and student performance. For example, views out windows improved performance by 5–10%, and performance dropped in classrooms where teachers were unable to control glare using window blinds (the authors postulated that glare could be the reason daylighting worsened student performance in this study). The authors concluded in the report that “windows and the resulting lighting quality in classrooms are very much a key issue in learning, and can have both positive and negative impacts on student performance.”
Retail sales
In any retail establishment, sales translate into profits, so any feature of the building that results in customers buying more stuff would be highly beneficial to store owners. Retail chains that carry the same merchandise in many stores and operate those stores identically present an opportunity to measure the effects of different building features. Earlier research on the influence of daylighting on retail sales by HMG (see EBN &EBN volume="8" number="9">Vol. 8, No. 9&/EBN>) was found to result in a dramatic—and inexplicable—40% improvement in sales in stores with natural skylighting compared with stores relying entirely on electric lighting.
In a new study, Daylight and Retail Sales, HMG sought to find out if these dramatic improvements could be replicated. They studied 73 stores of a California retail chain in which a third of the stores (24) had significant daylighting and the others had none. (The chain was not identified but represents a different retail sector than the earlier HMG retail study.) While the researchers were unable to duplicate the dramatic results obtained in the prior study, they did find a positive correlation showing that daylighting increased sales by 1–6%. More hours of daylighting were found to have a greater impact on sales. The presence of daylighting was found to be as good a predictor of sales improvement as such traditional measures as adequate parking and the absence of retail competitors. The daylit stores were found to be saving $0.24 per square foot ($2.60/m2) per year in energy, but even assuming the low end of the sales performance boost (1.1%), the bottom-line benefit from the boost in sales was 19 to 45 times as great as the energy cost savings.
While some have expressed disappointment that the new HMG studies do not fully corroborate their earlier studies, Heschong isn’t disappointed. “These studies, being larger, more detailed, and more complex, didn’t provide a sound-bite answer,” she told EBN. But a wealth of information can be gleaned from the new studies. “I find them more exciting and more compelling,” she said.
Creativity
In many white-collar jobs—advertising, for example—job performance depends on creativity, critical thinking, and focused collaboration with colleagues. If certain features of a building somehow inspire more creative thinking and result in the production of better ideas, those features would certainly be desirable. There are anecdotal claims that daylighting and other features of green building inspire creativity, but proving it is difficult.
An oft-told story in the annals of green building involves the Lockheed-Martin building mentioned above. Apparently, in addition to reducing absenteeism and boosting productivity, company managers concluded the design features increased creative output of employees and resulted in the company being awarded a lucrative $1.5 billion defense contract. This was so significant, so the story goes, that the company decided the building design features gave them a strategic advantage, and they ceased providing details about it to green building proponents—lest their competitors follow suit.
Healing
The speed at which patients recover from illness or surgery has a huge impact on the costs of healthcare, so health insurance companies and managed-care facilities have a strong incentive to do everything they can to promote recovery. Studies going back more than 100 years have found a clear link between building features and healing. The negative influences of certain building features, such as recirculating ventilation systems, have long been understood. More recently, experts have come to appreciate the positive influences of features like views to the outdoors. Research on both the negative and positive effects of building features on healing has increased in recent years as healthcare costs have risen and as we have learned more about disease transmission and about psychological influences on healing.
Dr. Roger S. Ulrich, currently a professor of architecture at Texas A&M University and director of the Center for Health Systems and Design, has been investigating the connections between human health and buildings (and plantings) since the early 1980s. In one of the most widely quoted investigations into this connection, Ulrich examined medical records of patients recovering from gallbladder surgery at the Paoli Memorial Hospital outside Philadelphia between 1972 and 1981. Using hospital records, patients were grouped into 23 pairs, each with similar age, sex, smoking habits, weight, nature of previous hospitalizations, and year of surgery. One patient in each pair recuperated from surgery in a room with a window looking out on a solid brick wall, while the other recuperated in a room looking out on trees (data was collected between May 1 and October 20, when trees were in leaf). Patients with the view of nature had significantly shorter hospital stays, elicited fewer negative comments from nurses, required less pain medication, and experienced slightly fewer surgical complications.
More recently, Ulrich and others have conducted clinical research showing the connection between plants and specific reductions in stress. In a 2002 paper at the conference Plants for People, he reported on a substantial body of research demonstrating that “stress and psychosocial factors can significantly affect patient outcomes,” and he argued that the psychological and emotional needs of patients should be addressed in healthcare facility design. He and R. F. Simons have demonstrated that viewing plants can lower blood pressure, reduce muscle tension, and speed recovery from stress. Dr. Judith Heerwagen and other researchers reported in a 1990 paper that a large mural hung on the wall of a dental clinic resulted in less stress among dental patients than was found on days when the wall was blank. Such findings are now being integrated into healthcare facilities nationwide.
Heschong believes this “evidence-based design” is a critical component of architecture. “The design community needs to define a basis for making decisions that’s based on evidence,” she argues. While we don’t understand the mechanisms at work—with the impact of views, for example—“the fact that it’s important is clear,” says Heschong. “Given that view is important for occupant performance and health, it suggests a radical transformation in how we design spaces in this country.”
What is Productivity Worth?
In a ground-breaking white paper, Greening the Building and the Bottom Line, published by the Rocky Mountain Institute (RMI) in December 1994, Joseph Romm, then of the U.S. Department of Energy, and Bill Browning, then of RMI, compiled information on the costs of operating a typical office building. For average U.S. office buildings in the early 1990s, energy amounted to $1.81/ft &SUPER>2&/SUPER>, repairs and maintenance $1.37/ft &SUPER>2&/SUPER>, gross office rent $21.00/ft &SUPER>2&/SUPER>, and office workers’ salaries $130.00/ft &SUPER>2&/SUPER> ($19.50, $14.75, $226.00, and $1,400.00/m &SUPER>2&/SUPER>, respectively). This was an eye-opening realization to a lot of people who had focused a tremendous amount of attention on shaving energy costs. On a per-square-foot basis, we were spending 72 times as much money on people in an office as we were on energy. That meant that even a tiny improvement in productivity or reduction in absenteeism could boost a company’s bottom line more than eliminating energy costs altogether. With productivity gains of 2–16% being bandied about in that paper, the potential for using productivity as a selling point for green design became very clear.
In the ten years since that paper was put out by RMI, these numbers have been refined a bit, but the basic findings are as impressive today as they were then. See the chart of typical building costs per square foot using data from the Center for Building Performance and Diagnostics at Carnegie Mellon University. &FIGURE>Typical office building costs in $ per ft &SUPER>2&/SUPER> per year.
Updated data provided by Carnegie Mellon University’s Center for Building Performance and Diagnostics
“If green buildings increase work performance by a very small percentage or reduce absence by a day or two per year, or cause people to work a few additional minutes per day, the economic productivity benefits will swamp the economic benefits associated with energy savings or reduced water use,” says Fisk. Nonetheless, he remains circumspect about drawing conclusions based on current research. “We do not have sufficient information to conclude that green buildings result in higher productivity,” he says. According to Fisk, researchers anticipate that some building design, construction, and commissioning measures employed in green buildings will lead to improved indoor environmental quality (IEQ), “but no scientific study of significant size has verified that green buildings have superior IEQ,” he told EBN. He believes that we still have a great deal to learn about the relationship between building features and occupant health and performance.
Kats, on the other hand, is ready to draw firm conclusions. A couple thousand studies worldwide, according to Kats, have examined the connection between buildings and human productivity or health. The bottom line, he argues, is that we have now learned enough to be able to state with confidence that various aspects of green buildings boost health and productivity. “We’re beyond the point of uncertainty,” he told EBN, noting that almost all of the studies show a positive correlation between high-performance buildings and health and productivity improvements—even if the degree of benefit is highly variable.
Loftness and her research team at Carnegie Mellon’s Center for Building Performance and Diagnostics (CBPD) are collecting the best information and aggregating it into the Building Investment Decision Support (BIDS) tool that allows easy access to that information. To date, 175 studies, including controlled experiments, individual building studies, and simulation studies, have been included in BIDS. The tool is sponsored and owned by the Advanced Building Systems Integration Consortium (ABSIC), whose current members include the architecture firm Astorino, Electricité de France, the Gale Foundation, the Northwest Energy Efficiency Alliance, Steelcase, Inc., Teknion, United Technologies/Carrier, the U.S. Departments of Defense and Energy, the U.S. General Services Administration, Public Works Canada, and Government Services Canada. ABSIC members have full access to the tool in exchange for the funding they have provided.
Plans are being developed to make BIDS available to the public through a fee structure in 2005, according to Beran Gurtekin, Ph.D., a staff member at CBPD. A demonstration is now online at cbpd.arc.cmu.edu/bidstrial. A companion tool funded by DOE, e-BIDS, is available to all.
An output graph from the online BIDS database is shown in Figure 1. This chart summarizes results from 13 case studies showing that access to the natural environment increases individual productivity between 0.4% and 18%. Another BIDS graph compares 15 case studies that show a 0.48–11% increase in productivity with improved indoor air quality. Other graphs show positive correlations of productivity with individualized temperature control, more ergonomic office furnishings, quieter offices, and higher-quality artificial light. While the range of improvement varies considerably, all of the BIDS data EBN examined show increased productivity from the building characteristics examined. &FIGURE>Figure 1. Results of Some BIDS Case Studies on Performance.
Source: Center for Building Performance and Diagnostics, Carnegie Mellon University
Speculations About Cause and Effect
To date, most studies on human productivity and buildings have sought to determine whether there is a causal relationship between various attributes of buildings and improved health and productivity. Few studies have sought to explain why we are seeing these effects. In some cases, the cause is easy to theorize—for example, when reduced colds or flu are observed in buildings with once-through fresh air via displacement ventilation, it is likely that germs are not dispersed widely.
But in most cases, the mechanisms of improved productivity are less obvious. For example, why would sales be higher in a retail store with skylights? It could be that the natural light shows off the merchandise better and it looks more enticing to shoppers. Or it could be that the space is more enjoyable or relaxing to be in, so shoppers take their time—and buy more stuff. Or it could be that employees are happier and, thus, more attentive to shoppers.
In an office environment, higher productivity may result from better lighting and reduced glare, but it could also result from far more subtle factors that stem from human evolution. The biophilia hypothesis suggests that humans have an innate love of the natural world that stems from our evolution. If buildings can mimic natural features, such as lighting conditions that change over the course of the day and spaces that provide a sense of refuge, so the argument goes, the occupants will be more content and that may translate into higher productivity. These same evolutionary influences may promote faster recovery for patients with some connection to the natural world.
Do Green Buildings Result in Higher Productivity?
Many of us in the green building field have championed productivity as a leading economic justification for pursuing a green-building agenda. Is this reasonable? Are these productivity-boosting features inherent in green buildings or coincident with them? There may be no hard-and-fast answer to this question. Indeed, it would be possible that a building shown to result in significant productivity benefits actually had few “green” features. There might be daylighting but no savings in electric lighting, or views through single-glazed windows, or lack of green building materials.
For the most part, however, the features that tend to enhance productivity and health in buildings also define a building as green. These include daylighting, displacement ventilation, views to the outdoors, natural ventilation, individually controllable ventilation and lighting, and avoidance of materials that offgas VOCs and other compounds that make people sick. So the short answer is, yes, green buildings—on average—do result in better health and improved human performance and productivity. We don’t know how much these buildings enhance productivity, and we aren’t close to understanding why these features boost productivity, but we are largely beyond the speculation stage as to whether there is a real effect.
Final Thoughts
In almost any business, higher productivity directly benefits the bottom line. If we can make the case that many of the features incorporated into green buildings contribute to higher productivity, it could have a huge impact on the marketability of green buildings. Evidence of such a correlation is accumulating. In retail establishments, studies show, daylighting results in higher sales. In healthcare facilities, features such as once-through displacement ventilation, avoidance of indoor contaminants, and access to views reduce risk of illness and promote healing. In schools, glare-free daylighting and views improve learning.
All of these claims, if further research bears them out, could well become the primary driver of green building over the next ten years. As noted, a mere 1% improvement in productivity can dwarf potential bottom-line benefits from energy savings, water savings, and reduced maintenance—though productivity need not be mutually exclusive of these other savings. In fact, a well-designed and properly constructed building can easily accomplish energy savings, water savings, and reduced maintenance while also increasing productivity.
As we look ahead, there are some very important research needs. According to Fisk, “we need research that quantifies the relationship of work performance with a variety of characteristics of buildings, building operation, and indoor environmental quality.” Fisk argues that once we establish them, “we can use these relationships in cost-benefit models to improve decisions about building designs and operation practices.”
This is a big agenda, but it is also very exciting. As the results pile up from productivity research, the real estate community and corporate America are beginning to pay attention. Productivity will almost certainly be one of the leading drivers of green building in the coming decade.
Published with permission from Environmental Business News.
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