26 SOLAR TODAY

Daylighting& Productivityat LockheedA daylit office building near San Franciscoadds to corporate profits through energysavings and improved productivity.

and support staff into a new 585,000-ft2

(54,300-m2) building in their office com-plex in Sunnyvale, California. In their firstyear in “Building 157,” they saved half amillion dollars on energy bills and severaltimes more due to reduced absenteeismand improved employee productivity. Pos-

In their first year in“Building 157,”Lockheed saved half amillion dollars onenergy bills and severaltimes more due toreduced absenteeismand improvedemployee productivity.

IBY BURKE MILLER THAYER

sibly even more significant for their bot-tom line, the higher productivity of em-ployees in Building 157 gave Lockheed a

n 1983, Lockheed Missiles andSpace Company (now LockheedMartin) moved a team of engineers

This daylit office building in Sunnyvale, California saves Lockheed Martin about $500,000 eachyear in energy bills. Higher employee productivity in the building, due largely to the daylightingdesign, saves even more.

competitive edge that helped them win acoveted $1.5 billion contract.

The key to Lockheed’s good fortune isthe building design itself. Soft daylightfloods the interior. Standing in the central“litetrium,” surrounded by trees, one getsthe sense of almost being outdoors. Mostimportantly, though, the employees loveit. They love where they work, and theyare more productive because of it.

When Lockheed hired the architecturalfirm of Leo A. Daly to design Building 157,Lee Windheim, the project architect, pre-dicted he could use passive solardaylighting design to cut the annual en-ergy bills in half. But until they saw howthe engineers responded to the new officeenvironment, neither Lockheed officialsnor the architects fully realized what a dra-matic impact daylighting could have onproductivity.

Design for the ClimateBuilding 157 sits in a sprawling com-

plex of Lockheed offices near San Fran-cisco, where the humidity is low and tem-peratures are mild. The winter lows rarely

dip below 40oF (4oC). And although thetemperature may reach 95oF (35oC) in thesummer, it cools off quickly in theevening. Given this mild climate and highinternal heat and humidity gains fromlights and occupants, a large commercialbuilding needs to lose heat and humidityto the outside most of the time. Therefore,the most energy-efficient insulation choicefor the walls and roof was none at all, andthe glass is all single-pane.

With virtually no heating load, lightingaccounts for over half the energy demandin Bay area commercial buildings, andcooling and ventilating make up the rest.This energy profile gave Windheim theperfect opportunity to use daylighting de-sign to save energy while pursuing hisnumber one objective—to improve thework environment.

Deep DaylightingAll aspects of the daylighting design

revolve around two simultaneous goals—to bring diffuse daylight deep into the of-fice space and to eliminate direct sunlightand minimize brightness at the work sta-

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Small gains inproductivity can make a

huge difference incorporate profits.

the architects call it, which spans from theground floor to the roof. At either end ofthe litetrium on each level is an additional60-ft (27.4-m) square office area. Daylightenters the building through glazing on thenorth and south walls and through theglazed cap at the top of the litetrium.

The architects eliminated east and westwindows in order to minimize heat gainand direct sunlight. Glass extends 15 ft(4.6 m) from floor to ceiling along the en-tire length of each office area on the north

shelf and the ceiling.While they maximized the diffuse day-

light entering the building, the architectswere careful to reduce brightness next tothe the north and south window areas andminimize direct solar heat gain from thesouth. To minimize heat gain from thesouth, a 2-ft (0.6-m) overhang shades theupper glass from direct summer sun, theexterior light shelves shade the glass be-low them and internal operable horizon-tal blinds cut out low-angled rays in thewinter. On the north, where sky bright-ness from the high windows could be aproblem for workers near the perimeter,the interior light shelves shade the workspaces below. The tinted glass installedbetween each light shelf and the floor be-low it blocks out about 60 percent of thelight on the north and more than 80 per-cent on the south.

High ceilings allow daylight from thelitetrium cap to penetrate about 45 ft (14m) into the office space on either side ofthe litetrium. The cap has a sawtoothshape to it, with four rows of vertical clearnorth-facing glass alternating with slopeddiffusing glass facing south. Light fromthe litetrium combines with light from theperimeter of the building to provide

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High windows above the light shelves allow deepdaylight penetration.

Daylight entering the building reflectsoff the internal light shelves and thesloped ceiling to provide diffuseambient lighting deep into the workareas.

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The “litetrium” in the center of the building creates an open,expansive feeling. Daylight from overhead provides ambientlighting for the surrounding office areas.

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and south sides. The height of theglass coupled with the downwardslope of the ceiling toward the in-terior is the key to the deep pen-etration of daylight. Daylight enter-ing through this glass suppliesadequate ambient lighting up to 45ft (13.7 m)—about 3 times theheight of the glass—into the officespace. The ceiling slopes from 15

ft (4.6 m) above the floor next to the win-dow to a 10-ft (3-m) height at 45 ft (13.7m) in. It then slopes backup to 15 ft (4.6 m) at theedge of the litetrium (seebuilding cross section,page 29). The slope of theceiling helps to intensifythe penetrating daylightby gradually decreasingthe distance from the re-flective surface of the ceil-ing to the work space be-low.

Along the north andsouth perimeters of eachlevel, a light shelf extends12 ft (3.7 m) into the officespace at about a 7.5-ft (2.3-m) height. The 6-ft (1.8-m) span of glass above thelight shelf is clear to allowas much daylight to enteras possible. Light com-ing through the glassbounces between the highly-reflective topsurface of the light shelf and the ceilingas it penetrates farther into the building(see section view, page 29). On the southside, exterior light shelves extend 4 feet(1.2 meters) out from the building at thesame height as the interior light shelves.Each exterior light shelf angles up andaway from the building at about 30 de-grees in order to reflect overhead sunlightinto the interior space between the light

daylighting to the entire 90-ft (27-m) widthof the office spaces on both the north andsouth sides. And although slightly moredaylight reaches the areas nearest thesouth side, the daylighting levels are re-markably uniform throughout the build-ing, with the “highest quality” (most even)light coming from north.

Integrated Electric LightingThe Daly architects fully integrated the

tions near the windows. The building lay-out and orientation, window placement,types of glazings, light shelves, ceilingsand “litetrium” are all part of an integratedplan to achieve these goals. The architectscarefully tested their design ideas withsmall-scale and eventually full-scale mock-ups before implementing them in the fi-nal building.

The five-level building is oriented about15 degrees east of south. Each level has a90-foot by 420-foot (27.4-meter by 128-meter) office area on the south and oneon the north. In the middle is a 60-foot by300-foot (27.4-m by 91.4-m) “litetrium,” as

28 SOLAR TODAY

Daylighting & Productivity

Lockheed Building 157 Project Details

Project Description: 3,000-Employee-Capacity Office BuildingOwner: Lockheed MartinArchitect and Engineer: Leo A. Daly Company:

Lee Windheim, AIA, Project Architect.General Contractor: Hensel PhelpsLocation: Sunnyvale, CaliforniaSize: 5-story, 585,000 ft2 (54,300 m2)Construction Cost: $50 millionDate Completed: 1983Heating Degree Days: 2439Cooling Degree Days: 498

ENERGY PERFORMANCEReference Case Building 157 % Reduction(California Code) (estimated)

Total 40,000 Btu/ft2/yr 20,000 Btu/ft2/yr 50 percent(454 million joules/m2/yr) (227 million joules/m2/yr)

HVAC: Variable volume HVAC system linked to central-complex heating/cooling plant.

DAYLIGHTING AND EFFICIENCY FEATURES• Elongated plan, with long axis on east/west orientation for favor-

able north/south glazing exposure and daylighting control.• Low shading-coefficient glass from floor to 7.5 feet (2.3 m) running

full length of north and south exteriors on each level.• 12-ft (3.7-m) interior light shelves running full length next to exte-

rior glazing on north and south sides on each level. Clear glassabove light shelves from upper surface of shelf to 6 ft (1.8 m) high.

• 4-ft (1.2-m) exterior light shelf on south side with angled reflectivesurface.

• Litetrium in center of building open from ground floor to roof witha cap of four “sawtooth” alternating rows of vertical north-facingclear glass and sloped south-facing diffusing glass.

• Sloped ceilings over north and south office areas on each level.• No glazing on east or west.• No insulation in walls or roof to facilitate loss of heat from internal

sources.• Fluorescent lighting with dimmable ballasts integrated with

daylighting through photocell sensors.

ADDED COST OF SOLAR/EFFICIENCY FEATURESActual Cost of Building 157 $50,000,000Predicted Cost of Reference $48,000,000Added Cost of Daylighting $2,000,000

ENERGY COSTSReference Building 157 Savings(estimated) (estimated)

Total $1,000,000/yr $500,000/yr $500,000/yr

ENVIRONMENTAL/HEALTH FEATURES• Continuous ventilation system• Daylighting• Plantings in litetrium and on all levels• Sound dampening materials and glass angles

tribution of the building to employee pro-ductivity is the most important design con-sideration. Small gains in productivity canmake huge differences in corporate profits.

The initial cost of designing and build-ing the new Lockheed office was about $50million. The architects estimate that thedaylighting features, including advanced

The ASES/PSIC Buildings for aSustainable America Education Campaignis a nationwide effort to make policymakers, buildingprofessionals and consumers more aware of the benefitsof applying sustainable energy principles to buildingdesign and construction. These benefits include increasedaffordability, more jobs, less environmental impact, reducedenergy consumption and improved health.

Here’s how Lockheed Building 157 stacks up:Energy50 percent overall reduction in total energy load

AffordabilityConstruction cost of $83/ft2 (896/M2)—about average forlarge office buildings in the San Francisco Bay area. Theadded cost for daylighting of $2 million is offset by energysavings of $500,000/yr. This translates to a simple paybackof about 4 years or a 25 percent annual return on invest-ment. The estimated savings due to improved productivityis in the range of $2 million or more per year.

Jobs and EconomyA portion of the money that Lockheed saves on energy isput back into the regional economy, which creates morejobs than if the money were spent on conventional energysupply. This is because conventional energy supply is oneof the most labor-intensive industries.

Health and ProductivityBy using daylighting, indoor trees and plants, continuousventilation and optimal acoustic design the Lockheed build-ing enhances the physical and mental well-being of itsoccupants. This contributes directly to employee produc-tivity.

EnvironmentThe Lockheed office complex is powered by a gas-firedpower plant. Although natural gas combustion makes a rela-tively minor contribution to air pollution, there are otherenvironmental costs associated with fuel exploration andproduction.

electric lighting system with thedaylighting design to optimize thequality of light in the building. In-stead of shining down from theceiling, the fluorescent lampspoint upwards and use the ceilingto reflect and diffuse their lightand blend it with the penetratingnatural light. The resulting illumi-nation is both physiologically andpsychologically optimal. Photocellsensors at the end of each lightshelf measure the daylight levelsand adjust the dimmable fluores-cent lamps accordingly to providean ambient brightness of between30 and 35 footcandles.

Mechanical SystemBuilding 157 is one of about

fifty Lockheed office buildingsconnected to a central heating andcooling plant. When the buildingcalls for air conditioning, chilledwater circulates from the centralplant through the building’s airhandling unit. About 80 percent ofthe time, the unit pulls air directlyfrom the outside because the out-side air is cooler and has less hu-midity than the air in the building.

Energy PerformanceThe architects ran computer

simulations of their design forBuilding 157 in order to predictenergy performance. Using a pro-gram (DOE-2.1) developed by theU.S. Department of Energy, theypredicted energy use for com-bined lighting, cooling and ventilating of20,000 Btu/ft2/yr (454 million joules/m2/yr). This is one-half the 40,000 Btu/ft2/yr(227 million joules/m2/yr) energy usespecified in the 1980 California energycode for new commercial buildings innorthern California. Although there are norecords of actual energy use for Building157 due to the nature of the Lockheed of-fice park’s central heating and cooling sys-tem, observers from the Lawrence Berke-ley Laboratory have informally confirmedthe predicted contribution of daylightingto the building’s lighting load.

By incorporating daylighting featuresin Building 157, the architects not onlyreduced lighting loads—they reducedcooling loads as well. The daylighting cutsdown on internal heat gain from electriclighting, thereby reducing the coolingload. (While daylighting can also be asource of heat gain, well-designed

daylighting brings less heatwith it per unit of illuminancethan any electrical lightingsource). According to Wind-heim, this dual reduction inlighting and cooling loads iswhy daylighting is such a suc-cessful energy design strategyfor commercial buildings.

A Life-Cycle Gold MineTo put the cost of a large

commercial building in perspec-tive, Windheim points out thata mere 2 percent of the total cost of Build-ing 157 over its useful life (life cycle cost)will be for the initial design and construc-tion. Another 6 percent will be spent onmaintenance costs (including energy),and employee salaries will account for theremaining 92 percent. This is why the con-

May/June 1995 29

Building Cross Section

lighting controls, addedabout $2 million over what aconventional building of thesame size and functionwould have cost. With over-all energy savings of 50 per-cent (about $500,000),Lockheed recovered its ad-ditional investment in about4 years. From a long-term in-vestment point of view, thecompany is reaping a guar-anteed annual return of 25percent on energy savingsalone.

In the case of Building157, the energy savings, asimpressive as they are, areovershadowed by the rewards of improvedemployee productivity. To illustrate thispoint, we’ll assume that the average sal-ary of the Lockheed engineers and staffis $50,000/year and that absenteeism (asimple measure of productivity) is down15 percent (an unofficial figure attributedto company officials) from a level of 7 per-cent (14 days per year). A 15 percent im-provement on 7 percent absenteeismyields a 1 percent improvement in produc-tivity. Every 1 percent gain in productiv-ity in Building 157 is worth $500 per em-ployee ($50,000 salary times 1 percent), or$1.5 million ($500 times 3,000 employees)per year. This is 3 times the energy sav-ings. And although these numbers aremerely illustrative, Lockheed officials haveprivately acknowledged that their gains inproductivity offset the $2 million dollarextra cost for the building in the first yearof occupancy.

The Productivity StoryOf course absenteeism is only one

among many ways to assess productivity.

South Wall SectionNorth Wall Section

One could also assume that employeeswho find their building more enjoyableand comfortable to be in will exhibit morepositive attitudes toward work and be ableto concentrate more fully on their tasks.Every minute less of wasted time per hourrepresents a 1.67 percent gain in produc-tivity. In Building 157, 2 percent more pro-ductivity means another $3 million in sav-ings. And while impossible to confirm,even very small gains in productivity forcompanies like Lockheed can mean thedifference between winning and losingmajor contracts with profits in the manymillions of dollars.

Although it is difficult to document theimpact of daylighting design on employeeproductivity, the story of Building 157 is acompelling one. When Joe Romm of theDepartment of Energy and Bill Browningof the Rocky Mountain Institute spokewith employees during a recent tour, theyfound that the engineers and support staffwere, without exception, enthusiasticabout their office environment. Althoughthey praised many features of the build-

ing, including acoustics andaesthetics, the quality oflighting and the open, spa-cious feeling created by thecentral litetrium were at thetop of their list.

The kind of praise re-ported by Romm andBrowning and others sup-ports Lee Windheim’s firmbelief that daylighting canhave a major impact on pro-ductivity. According toWindheim, “Daylighting isthe very best way to achieveboth energy savings and ahigher-quality office envi-ronment at the same time.”

Both of these achievements due todaylighting contribute to the bottom lineof corporate profits. What’s more, theycontribute to a better environment andhealthier employees. All told, daylightingis a design strategy that American com-panies and architects can no longer affordto ignore. !

Burke Miller Thayer is an environmental edu-cator and writer living in Nederland, Colorado.He can be reached through the American SolarEnergy Society, 2400 Central Avenue, Unit G-1,Boulder, Colorado 80301, (303) 443-3130, FAX(303) 443-3212.

This is the seventh in a series of twelve SOLARTODAY articles describing successful sustainableenergy buildings throughout the U.S. The first sixarticles are available as a full-color reprint from theAmerican Solar Energy Society. The series is part ofthe Buildings for a Sustainable America EducationCampaign, co-sponsored by ASES and the PassiveSolar Industries Council. This article was written forthe Office of Building Energy Research, U.S.Department of Energy (DOE), through the NationalRenewable Energy Laboratory in Golden, Colorado,a DOE national laboratory.