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If Sun Shines In, Workers Work Better, Buyers Buy More

November 20, 1995 GMT

Daylight is coming back.

Ever since the first cave people crept indoors for safety, humans have sought to bring sunlight in from outside. The late architect Mies van der Rohe even argued that ``the history of architecture is the history of man’s struggle for light _ the history of the window.″

The struggle suffered a major reversal in 1879, when Thomas Edison invented the electric light. After that, most architects relied more and more on man-made light. ``A very small percentage of our buildings have adequate `daylighting,‴ says Robert Birkebile, a Kansas City, Mo., architect.


Recently, though, European countries have begun to require that a certain percentage of a building’s light come from outdoors _ 37 percent in the Netherlands, for example. And in the U.S., the ``daylighting″ movement, which was founded on dollars-and-cents arguments about energy efficiency, has begun to cite even greater gains from higher productivity.

According to a report by the Rocky Mountain Institute, Snowmass, Colo., increased daylighting results in fewer days lost to absenteeism and fewer errors and defects. The report, ``Greening the Building and the Bottom Line,″ cites improved heating and cooling in eight commercial buildings. And the authors, Joseph Romm and William Browning, describe specific gains:

_ In 1993, Wal-Mart Stores Inc. opened a prototype store in Lawrence, Kan. The lead designer was BSW Architects, Tulsa, Okla. Called the Eco-Mart, the store experimented with a variety of design elements, including nine special skylights created by Andersen Corp., Bayport, Minn.

The Eco-Mart cost about 20 percent more to build than other Wal-Mart stores. To hold down construction costs, the company decided to install the special skylights in only half the roof, leaving the other half with artificial light.

Wal-Mart claims energy savings from drawing natural light through the skylights. But ``something else has gotten the corporation’s attention,″ says the institute. In every Wal-Mart store, each cash register is connected in real time back to headquarters in Bentonville, Ark. According to Tom Seay, who was then the company’s vice president for real estate, sales were ``significantly higher″ in those departments in the daylit half of the store, and they were also higher there than in the same departments at other stores.

Employees in the half without daylighting continue to try to have their departments moved to the daylit side. Andersen has also developed an improved skylight for the Wal-Mart store that’s due to open in January in City of Industry, Calif.

_ In 1979, the architectural firm of Leo A. Daly, Omaha, Neb., offered to design a new office building for 2,700 engineers and support people working for Lockheed Corp. in Sunnyvale, Calif. Daly promised that the building would use half as much energy as the one Lockheed was planning.

The aerospace company took up the challenge. Opened in 1983, Building 157 has 15-foot-high window walls with sloped ceilings to bounce daylight deep inside. A central atrium runs five stories top to bottom and has a glazed roof. ``Light shelves″ on the south facade shade out the high summer sun but diffuse the lower winter light and reduce glare.

Employees say they love the building. ``By nature I’m very cynical, but the conditions in this building are far superior to any I’ve experienced in 30 years in the aerospace industry,″ says one engineer.

Daylight has also saved Lockheed 75 percent of its lighting bill and cut overall energy costs in half because daylight generates less heat than artificial light and requires less air conditioning. The $2 million in energy improvements paid for themselves in energy savings in four years.

What Lockheed hadn’t expected was that productivity would rise because absenteeism would decline. The company doesn’t discuss figures, but the report says absenteeism dropped 15 percent, which paid for 100 percent of the improvements in the first year. Architect Lee Windheim quotes Lockheed officials as saying increased productivity also won the company a very competitive $1.5 billion defense contract.

_ In 1987, Nederlandsche Middenstandsbank opened a new headquarters in Amsterdam that bank officials hoped would be ``organic, which integrated art, natural materials, sunlight, plants, energy conservation, low noise and water.″ Instead of a monolithic tower, the 538,000-square-foot building is broken up into 10 slanting towers, laid out in an S-curve with gardens and courtyards over parking and service areas. No desk is more than 23 feet from a window, and interior louvers in the top third of windows bounce daylight onto office ceilings.

These and other measures to conserve energy paid for themselves in just three months. Meanwhile, absenteeism among NMB employees has dropped 15 percent.

Other researchers have found other benefits to daylighting. Roger Ulrich of Texas A&M University studied gall-bladder surgery patients housed on both sides of a corridor at a nursing unit. On one side the rooms looked out at a brick wall, on the other, at tree-dotted lawns.

The patients with the tree view had fewer postoperative hospital stays and fewer negative evaluations from nurses. They also took fewer pain relievers and had fewer minor postsurgical complications.

Most of the gains ascribed to daylighting come from simple architecture rather than complex high technology. Architects and engineers in the daylighting movement tend to limit their high tech to nonmoving glass and lenses. Eighty-five percent of the solution, says Mr. Birkebile, the architect, is ``orientation of the building for the solar angles rather than for the way the street goes, and designing the building’s original skin to accept the winter sun while rejecting the summer sun.″

``The more low-tech the better,″ adds Nancy Clanton, an electrical and lighting engineer in Boulder, Colo. ``It costs less and it lasts longer.″

So what are the arguments against more daylight in buildings? Harry Gordon, a Washington, D.C., architect, notes that electrical lighting is becoming more efficient. As this happens, the savings from daylighting decline. Like his colleagues, Mr. Gordon, who chairs the American Institute of Architects’ Committee on the Environment, advocates a ``balance″ of the two kinds of light.

Mr. Birkebile adds that architects should proceed cautiously with daylighting. ``We need sun, but sun also causes skin cancer and eye disease,″ he says.