DESIGNING WITH THE SUN
The first step in creating comfort and thermal delight in buildings is to understand
the relationship between the climate and our need for shelter. There is
an enormous variation in climates that buildings experience. These can be at
the scale of global climates, from the Arctic to the Sahara. They can be
regional climates in the centre of a continent or on the seashore. They can be
local climates on the sunny or the shady side of a hill or street. All will influence
the way in which a building should be designed in relation to the sun.
The sun can be a friend or an enemy in buildings. Poor climatic design of
buildings, all too often seen in ‘modern’ architecture, causes many buildings to
overheat, even in temperate or cold climates where such problems traditionally
never existed. The power of the sun should be understood and respected
by good designers of well-designed, passive solar buildings in which the free
energy of the sun is used to power the building but not allowed to interfere
with the comfort and economy of the building’s occupants.
The five things a designer needs to know for a good passive solar design are:
1 how strong the sun at the site is at different times of the year
2 where the sun will be at different times of the year in relation to the site
3 how much of the sun’s heat a building will need, or not need, at different
times of the year to enable the building occupants to be comfortable
4 how much storage capacity the building should have in relation to the
available solar gain at the site to meet those needs
5 what the additional requirements are for controlling the heat gain from
direct solar radiation, convection or conduction in a design and how they
can be met by envelope performance, building form and ventilation.
There are a number of factors that influence the incidence, or strength, of
solar radiation at the site including:
• the latitude of the site
• the altitude and azimuth of the site
• how much shade will be given by any obstacles that exist between the
building and the site
• the weather above the site.
AZIMUTH AND ALTITUDE OF THE SUN AT A SITE
The angle with which the sun strikes at a location is represented by the
terms altitude and azimuth. Altitude is the vertical angle in the sky (sometimes
referred to as height); azimuth is the horizontal direction from which it
comes (also referred to as bearing). Altitude angles range from 0° (horizontal)
to 90° (vertical: directly overhead). Azimuth is generally measured clockwise
from north so that due east is 90°, south 180° and west 270° (or 90°).
Because the Earth revolves around the sun once a year, we have four seasons.
The Earth’s axis remains in a constant alignment in its rotation so
twice a year the incoming solar radiation is perpendicular to the latitude of
the equator and only once a year is it perpendicular to the tropics of Cancer
and Capricorn,
The changing values of azimuth and altitude angles are predominantly a
reflection of the changes in the relative positions of Earth and sun. These are
governed by:
• the rotation of the Earth around the sun
• the rotation of the Earth about its axis.
One of the simplest tools we can use for the derivation of altitude and
azimuth angles is a graph using Cartesian coordinates
incorporates two types of line. Firstly, those representing the variation in altitude
and azimuth over the period of a day (given for the 21st or 22nd day of
each month). Secondly, those joining the points on the altitude–azimuth lines
for a specific hour. Thus the solar angles for 11 a.m. on 21 March may be read
off on the horizontal and vertical axes where these two lines meet (altitude
36°, azimuth 19°). Values for other days may be read by interpolating between
these lines.
It may appear that these are the only determinants of angular position,
however we are actually concerned with the direction of the sun’s radiation
rather than the Earth–sun position. Also, radiation does not travel in an
entirely straight line but is bent slightly by the Earth’s atmosphere.
The distance between the Earth and the sun is approximately 150 million
km, varying slightly through the year with the variation of the azimuth and
altitude angles with time.
All passive solar features involve the transmission of solar radiation through
a protective glazing layer(s) on the sun side of a building, into a building space
where it is absorbed and stored by thermal mass (for example thick masonry
walls and floors or water-filled containers). The typical processes involved are:
• collection – to collect solar energy, double-glazed windows are used on
the south-facing side of the house
• storage – after the sun’s energy has been collected, some heat is immediately
used in the living spaces and some is stored for later use. The storage,
called thermal mass, is usually built into the floors and/or interior walls.
Mass is characterised by its ability to absorb heat, store it and release it
slowly as the temperature inside the house falls. Concrete, stone, brick and
water can be used as mass
• distribution – heat stored in floors and walls is slowly released by radiation,
convection and conduction. In a hybrid system, fans, vents and
blowers may be used to distribute the heat.
There are several types of passive solar system that can be used in homes. The
most common are direct gain, indirect gain and isolated gain.
SYSTEM COMPONENTS
There are three key components to all passive solar systems for heating:
• collector
• mass
• heated space.
DIRECT GAIN SYSTEMS
Direct gain systems are most commonly used in passive solar architecture.
The roof, walls and floor are insulated to a high level. Solar radiation enters
through the windows and is absorbed by the heavy material of the building.
The whole building structure gradually collects and stores solar energy during
the day. Heavy building materials provide thermal storage. The collected
solar energy is gradually released at night when there is no solar gain.
Direct gain systems commonly utilise windows or skylights to allow solar
radiation to directly enter zones to be heated. If the building is constructed
of lightweight materials, mass may need to be added to the building interior
to increase its heat storage capacity. The proportion of a building’s heating
needs that can be met by solar energy increases as the area of sun-facing
glazing increases. Additional mass must therefore be used to reduce interior
temperature swings and delay the release of solar energy into occupied
spaces. While the mass that is directly illuminated by the incident energy,
sunshine, is the most effective for energy storage, long-wave radiation
exchanges and convective air currents in the solar heated rooms allow nonilluminated
mass to also provide effective energy storage.
In order to understand the thinking behind green building principles it is necessary
to remember why we should be so concerned with such issues in the construction
industry. Perhaps producing more energy from renewable sources and protecting
wildlife and habitats is much more important? Indeed there are many who do not
give green building a high priority. It is surprising how many environmental
groups, for instance, appear to attach a low priority to their built environment.
Groups concerned with the natural environment, wildlife, habitats and so on,
sometimes inhabit or build dreadful buildings using toxic materials and high
embodied energy materials.
Many others see the issue purely in terms of energy efficiency or more
specifically fuel efficiency and are largely unconcerned about the environmental
impacts of the materials which they use to achieve reductions in gas, oil and
electricity bills. Government and European research and development
programmes such as Joule/Thermie, Save and Altener or the UK Clean
Technology programme seem largely designed to encourage high technology
development, leading to new and more products and systems which will expand
industry and create new markets.
When the four main principles set out above are taken into account, it becomes
clear that the building materials industry, the transport of materials and products,
their construction on site and then the pollution and energy wastage coming from
buildings collectively has a surprisingly wider impact on the environment than
most other human activities. The Vales have suggested that 66% of total UK
energy consumption is accounted for by buildings and building construction and
services.10 Thus the importance of buildings and the construction industry has to
be seen as one of the most, if not the most important user of energy and resources
in advanced society.
Major savings will not be achieved only by putting more insulation in homes
or using low energy light bulbs, a much more fundamental review of all building
materials production and construction methods, transportation etc. is required.
Thus if we are concerned about ozone depletion, wastage of limited natural
resources, such as oil, gas and minerals, the loss of forested areas, toxic chemical
manufacture and emissions, destruction of natural habitats and so on, tackling the
built environment is going to go a long way to addressing these issues.
We’ve been talking about green buildings in general. Now let’s get a little
more speciŠc about what we actually mean by the term“green building.”
Utilizing the LEED system of the US Green Building Council, introduced
in the previous chapter, a green building is one that is built considering the
following Šve factors. However, most green buildings do not incorporate
all of these measures, but rather the project team picks and chooses those
that are appropriate for a project’s budget and goals.
1. Promote Selection of Appropriate Sites and
Environmentally Sustainable Site Development
• Locate projects on sites away from wetlands, above the 100-year šood
level, away from prime agricultural land and away from endangered
or threatened species habitat.
• Locate projects on sites where there is already urban infrastructure to
serve them.
• Locate projects on brownŠeld sites that have been remediated of contamination;
these usually have infrastructure already in place.
• Provide opportunities and building infrastructure for people to commute
to work using public transit and bicycles.
• Minimize parking to discourage excessive auto use.
• Provide low-emission vehicles and car-sharing arrangements to reduce
gasoline use.
• Protect open space in site development and restore open space on already
impacted sites.
• Manage stormwater to reduce the rate and quantity of stormwater
runoª, and use best practices to clean stormwater before it leaves the
site.
• Manage landscaping and parking lots to reduce excessive areas of
open pavement that cause heating of the area around a building in
summer, leading tomore air-conditioning use.
• Control interior and exterior light from leaving the site, helping to
make skies darker at night.
2. Promote Efficient Use ofWater Resources
• Control irrigation water use for landscaping, using as little as possible.
Select native landscaping which demands little or no added water.
• Look for alternative ways to reduce sewage šows from the project,
possibly even treating the wastewater onsite.
• Use water-conserving Šxtures inside the building, to reduce overall
water demand.
3. Conserve Energy, Use Renewable Energy and
Protect Atmospheric Resources
• Reduce the energy use (and environmental impact) of buildings 20%
ormore below the level of a standard building.
• Use onsite renewable energy to supply a portion of the building’s electrical
and gas (thermal energy) needs, using solar photovoltaic (PV)
panels or solar water heating.
• Commission the building by verifying the functional performance of
all energy-using systems after they are installed but before the building
is occupied.
• Reduce the use of ozone-harming and global-warming chemicals in
building refrigeration and air-conditioning systems.
• Provide a means to troubleshoot the building’s energy use on a continuing
basis by installingmeasuring andmonitoring devices.
• Supply 35%ormore of the building’s electrical supply with purchased
green power fromoªsite installations, typically fromwind farms.
4. Conserve BuildingMaterials, Reduce ConstructionWaste
and Sensibly Use Natural Resources
• Install permanent locations for recycling bins to encourage the practice
in building operations.
• Reuse existing buildings, including interior and exterior materials, to
reduce the energy use and environmental impacts associated with
producing new buildingmaterials.
• Reduce construction waste disposal by 50% or more to cut costs and
reduce landŠll use.
• Use salvaged and reclaimed building materials such as decorative
brick and wood timbers that are still structurally sound.
• Use recycled-content building materials that are made from “downcycled”
materials such as recycled concrete, dry wall, šy ash fromcoalŠred
plants and newspapers.
• Use materials that are harvested and processed in the region, within
500 miles, to cut the transportation impacts associated with bringing
themfromfarther away.
• Use rapidly renewable materials that have a ten-year regeneration
time or less, such as bamboo, cork, linoleum, wheatboard or strawboard
cabinetry.
• Purchase 50% or more of the wood products in the building from
forests certiŠed for sustainable harvesting and good management
practices.
5. Protect and Enhance Indoor Environmental Quality
• Provide non-smoking buildings, or separate ventilation systems
where smoking is allowed (such as in high-rise housing).
• Monitor delivery of outside air ventilation so that it responds to demand
by using sensors for carbon dioxide levels to adjust air šow.
• Provide for 30% increased ventilation above code levels, or natural
ventilation of indoor work areas, to increase the amount of healthy air
in the building.
• Conduct construction activities so that there is clean air at the startup
of systems and no dust ormoisture inmaterials such as ductwork and
sheet rock. The idea is to get rid of “new-building smell” and its associated
toxicity.
• Use low-emittingmaterials in the building to reduce sources of future
contamination, including oª-gassing frompaints and coatings, adhesives
and sealants, carpets and backing and composite (or engineered)
wood or agriŠber products.
• Make sure that areas where chemicals are mixed or used (such as inhouse
printing plants or large copy rooms) are separately ventilated,
and install walk-oª mats or grilles at building entrances to capture
contaminants before they enter the building.
• Provide for individual thermal comfort of building occupants, with
respect to temperature and humidity.
• Provide for occupant control of building lighting and ventilation systems.
• Provide for adequate daylighting of interior work spaces, using both
vision glazing and overhead light sources such as skylights and roof
monitors (vertical glazing).
• Provide for views of the outdoors from at least 90% of all workspaces
so that people can connect with the environment.
In Your Office orWorkplace
There are many things you can do where you work to promote green
buildings and sustainable design.Here are a few brief suggestions you can
implement right away.
Reducing Your Carbon Footprint
In early 2007 Swiss Re, amajor global insurance company, announced that
it would be supporting investments and purchases made by employees
that contribute to reducing carbon dioxide emissions. The new “COYou2
reduce and gain” program is part of Swiss Re’s commitments supporting
the Clinton Global Initiative. In 2003 Swiss Re declared that it wouldmake
its own operations carbon neutral by 2013. Now, as part of the Clinton
Global Initiative, Swiss Re has decided to support measures taken by its
employees that contribute to the reduction of CO2 emissions.
The “COYou2 reduce and gain” program supports employees’ investments
in measures that contribute to reducing greenhouse gas emissions,
particularly in relation to mobility, heating and electrical energy. Such
measures, which vary according to regional circumstances and preferences,
include low-emission hybrid cars, use of public transport and the
installation of solar panels or heat pumps. Fromnow until the end of 2011,
Swiss Re plans to rebate each employee one-half of the amounts invested
in these measures, up to a maximum per employee of 5,000 Swiss francs
(about $4,000) or the equivalent in local currency.
According to Ivo Menzinger, Head of Sustainability & Emerging Risk
Management,who is in charge of the “COYou2 reduce and gain” program,“Swiss Re is actively engaged in mitigating climate change and its consequences.
This program is an investment that will encourage our employees
to make a personal contribution and further raises awareness of the
issue.”1
Take action with your company or business. Some easy steps to take
include:
• If you operate a šeet of vehicles, convert them all to hybrids and cut
your normal gasoline consumption by 35%to 50%.
• Subsidize employees’ use of public transit, at least 50%ormore.
• Discourage single occupancy vehicle use by not paying for parking.
• Provide secured bicycle storage in your building with shower facilities
or nearby health club passes to encourage people to ride to work in
good weather. (This is also a great “wellness” initiative.)
• BuyGreen Tags or other “carbon oªsets” to cover 100%of your annual
travel mileage by car, bus, ferry and airplane. (There are a large number
of organizations that cater to this need.)
• Buy green power for the electricity consumption of your workplace;
wind-generated power is widely available froma large number of reputable
organizations;make sure it is “Green-e” certiŠed fromthe Center
for Resource Solutions.2
• Begin the journey to sustainability by examining all of your operations,
to see how to reduce their environmental footprint; this activity
can involve everyone in the organization; even simple steps like eliminating
wastebaskets under individual desks in favor of paper recycling
boxes sends a simplemessage, as does having the IT department set all
the printer default setting to “duplex” so people will stop printing on
one side of the paper for internal use.
• Undertake a LEED-EB assessment of your existing building operations;
LEED for Existing Buildings is a comprehensive evaluation and
benchmarking system that will help you “green” your operations and
engage the entire workforce in the eªort.
• Buy laptops and šat-panel monitors for everyone to cut energy use
from “plug loads,” often 20% or more of the total energy use of an
o‹ce.
• Re-lamp and install lighting controls, so you are using only the most
e‹cient Šxtures and lights don’t operate when people aren’t using a
roomor o‹ce.
• Join the US Green Building Council as a corporate or agencymember
and become part of the solution; once you join, everyone in the company
or agency can enjoy themembership beneŠts.• Study all of the other aspects of your business operations and work to
change each aspect, over time, to more sustainable options, then encourage
employees to take those same principles home.
In Your Home or Apartment
The most powerful agent of change is your own personal experience.
Think of what you can do to promote green buildings and green operations
where you live.Here are a few examples:
• Start keeping track of your gas, electricity and water use, along with
the number of gallons of gasoline purchased and airlinemiles šown.
• Try to cut down on energy and water use by 10% in the next year by
examining all of your habits and seeing where you can combine trips
or cut down on optional travel.
• Go even beyond 10% reduction: create a “year of living sustainably”
that commits you to dramatic changes in lifestyle tomeet sustainability
goals; if you have kids, enlist their help and creativity. It will
strongly supplement the education they’re typically getting in school.
• If you can’t stop traveling, because of your job or family needs, then
start by purchasing “carbon oªsets” or Green Tags for all of your
mileage, so that you’re oªsetting their impact with clean power or tree
plantings somewhere else.
• Buy a hybrid car or a more fuel-e‹cient vehicle; you can Šnd the top
ten green cars each year listed by the American Council for an Energy-
E‹cient Economy.3
• Look into state and federal incentives for installing solar electric and
thermal systems on your home; if you’re a renter, discuss the beneŠts
of doing this with your landlord ormanagement company.
• Call the local gas or electric utility company and ask for a home energy
audit to Šnd out what are the “low-cost/no-cost” things you can
do to cut down on energy consumption; in some areas, the local water
company will oªer technical assistance or free kits for cutting water
consumption.
• Install dual-šush toilets to cut water use fromtoilet šushing by half or
more; install other water-conservingmeasures such as drip irrigation.
• Form a neighborhood “sustainable living” group to engage the creativity
of others in Šnding additional ways to cut energy and water
use, reduce the use of poisons in landscapemaintenance and enhance
local recycling eªorts.
• Consider your purchasing patterns and their “upstream” impacts, including
waste in production, transportation costs (if made far fromwhere you live) and embedded energy of production, distribution,
use and disposal.
• For home remodeling, try to support local retail stores that specialize
in sustainable products, such as healthy paint and carpet and reclaimed
or salvaged buildingmaterials.
Your Town, City or State: The Power of Local Initiatives
Just as “all politics is local,” a statement famously attributed to former
speaker of the US House of Representatives Tip O’Neill, all successful sustainability
eªorts have their roots in local action.Withmore than 16 states
and 60 cities (as of early 2007) oªering local initiatives to promote green
buildings, there is ample precedent for you to engage your local school
board, city council, country board or commission and even state representatives
in this eªort.Drill down into each green building success story and
you will Šnd just a few local people, some in government, some in business
and some plain citizens, whose energy and foresight have made the diªerence.
Some of the initiatives already enacted, on which you can model
your eªorts, include:
• At the local level, secure a commitment from a school district, city or
county to build all future buildings and schools to at least the LEED
Silver level; some communities have committed to build LEED Gold
projects (the earliest on record was the City of Vancouver, British Columbia);
this may take some doing because you’re going to hear the
old familiar refrain “it costs too much,” and you’ll have to convince
people otherwise by using the examples in this book; among theNorth
American cities making this commitment are Seattle, Sacramento,
Portland (OR), Tucson, San Francisco, Calgary andMadison (WI).
• Some cities are taking the next step after greening their own operations,
requiring larger private-sector projects to meet LEED certiŠed
or Silver-level certiŠcations within the next few years. (Large cities
such as Boston andWashington, DC, have done this, and more cities
will be requiring such achievements or incorporating LEED requirements
and Architecture 2030 milestones into the building code in the
next few years.)
• If you have a municipal electric utility or public utility district, convince
it to oªer incentives for energy conservation and solar energy
systems; often the large cash šows of a utility permit it to oªer incentives
that will, over time, allow it to oªset expensive purchases of additional
generating capacity in the future; in Texas,Austin Energy, amunicipal
utility, has been promoting green homes since the early 1990sand has one of the most successful green home rating systems in the
country.
• Convince your mayor or city council to sign onto the USMayors’Climate
Protection Agreement, which commits cities to becoming carbon
neutral within the next decade, or sooner, in their own operations;
4 at the global level, former US President Clinton’s Climate
Change Initiative is engaging the 40 largest cities in the world to become
carbon neutral over the next 20 to 30 years.5 (Already, London
has signed on to this initiative.) In Denver,Mayor John Hickenlooper
has been aggressively promoting the Greenprint Denver plan for
sustainable development,6 and in Chicago, Mayor Richard Daley has
vowed to make Chicago the “greenest city” in North America by promoting
green buildings, green roofs and street tree plantings.
• Convince your city council or country commission/board to oªer incentives
to private sector projects that commit to building green; successful
incentives include faster processing of building permits andincreased“density bonuses” for high-rise o‹ces, apartments and condominium
developments; if you know a state legislator, talk to them
about sponsoring state initiatives to promote green buildings and renewable
energy; successful initiatives have included personal and/or
corporate income tax credits (Oregon and New York, along with 23
other states); property tax abatements for LEED Silver or better certiŠcations
(Nevada); sales tax elimination on solar systems (Arizona,
Florida, Georgia, Idaho, Iowa, Massachusetts, Maryland and 12 other
states); and rebates for purchase of solar systems (California,Arizona,
Colorado and 30 other states).7
• Have the governor or state legislature require the state utility commission
to have all investor-owned utilities collect a tax on utility bills and
oªer “public purpose” funds for investments in conservation, onsite
power and renewable energy; in 2007 the California Public Utilities
Commission adopted an incentive payment system in the form of a
consumer rebate, to encourage people to install photovoltaic systems
on their roofs; the goal is “amillion solar roofs”within ten years.
Daylighting is an aspect of green building design that should be ubiquitous;
without adequate daylighting, people will not perform well and will
not be healthy. For building plans, this implies a design that is no more
than 66 feet wide, front to back, or about 33 feet to a window from any
workstation. This is a standard design requirement in many places in Europe,
where people’s health is placed before economic e‹ciency. Looked at
another way, a building should be oriented so that the long axis is eastwest;
this allows for maximum daylighting, from both south- and northfacing
windows.
Daylighting’s beneŠts are immediately apparent; people see better and
feel better whenever there is natural light for reading and working. Good
daylighting design can employ skylights, north-facing windows on the
roof, a central atrium, light shelves to bounce light into a space while shading
windows from the summer sun, and other techniques. Good daylighting is always indirect, without glare.Daylighting is usually combined with
electric lighting, so that there is a constant lighting level, typically 30 footcandles
at the desktop, or there is task lighting provided for each workstation.
According to a report from Carnegie Mellon University analyzing
daylighting research,“Eleven case studies have shown that innovative daylighting
systems can pay for themselves in less than one year due to energy
and productivity beneŠts…the ROI [return on investment] for daylighting
is over 185%.”38
A California study of the impact of daylighting examined 73 stores of
a chain retailer, of which 24 had daylighting. The results:
The value of the energy savings from daylighting is far overshadowed
by the value of the predicted increase in sales due to daylighting.
The proŠt from increased sales associated with daylight
is worth at least 19 times the energy savings.
As we showed earlier, a main barrier to implementing green buildings has
been the perceived cost increases for green measures. It is true that many
of the earlier green projects in the 2000 to 2005 period were more costly.
This is largely because the transition to new methods of design and construction
involves a lot of social learning that is accompanied by construction
mistakes, poor designs, unproven new products and a myriad of reasons
leading to extra costs. By 2005 and especially in 2006, however,many
design and construction teams had done enough green projects to start
lowering costs tomore conventional levels.
In 2006 the developer of a large LEEDPlatinumproject in Portland—
a very complex, 412,000-square-foot, mixed-use medical facility — reported
a cost premium (net of local, state and federal incentives) of about
1%on a $145million project.30 Now, this developer had designed and built
30 prior LEED projects and used a very experienced architect and engineering
team, already well-versed in green building methods. But their
success does point to the fact that future green buildings can be built without
any initial cost premium, once design and construction teams garner
enough experience.
What determines the cost of a green building?
• First and foremost, it depends on what the design teamand owner are
trying to achieve. If it’s a LEED Platinum building, they most likely
will use green roofs and photovoltaics, two expensive additions to a
project that may not be included in a LEED Silver or possibly even a
LEED Gold project.
• Second, it depends how early in the process the project decides to pursue
sustainable design and construction.As we show in the section on
integrated design, it’s best if that decision is made as early as possible,
even during the site selection process, so that a building can be properly
oriented, with a rectangular shape that allows for good daylighting
and e‹cient passive solar designmeasures.
• Third, it depends still on the experience of the design and construction
team with green buildings; the more experience, the less the cost
premium based on both fear of the unknown and lack of knowledge
about sourcing green products, for example. Less-experienced teams
often use green building consultants to help them out with their Šrst
project, to accelerate the learning curve.
Integrated design often leads to creative solutions that allow teams to
“tunnel through the cost barrier” and design a more energy-e‹cient
building at a lower initial cost.31 Typically, this is done by having the architecture
do some of the work of cutting energy use, as well as heating and
cooling a building with daylighting, shading devices, highly e‹cient windows,
orientation and heavy mass construction. Green buildings can also
cut other project costs by saving on infrastructure investments and connection
charges for storm drainage and sewage connections through total
water system management. Often, by thinking strategically in the Šrst 30
days of a project, you can inšuence 65% of total costs by assessing a
broader range of options,making choices among key cost drivers and having
a clear vision of results. This puts a premiumon thinking (vs. doing), a
concept thatmany Americansmay Šnd challenging.
One of the most widely cited studies of the costs of green buildings
was done by the international cost-consulting ŠrmDavis Langdon in 2004
and updated early in 2007. Using their own proprietary database of actual
building costs, and comparing 45 LEED projects with 93 other non-LEED
projects, Davis Langdon discovered that green building costs (for three
types of common projects—libraries, academic classrooms and laboratories)
were statistically no diªerent than conventional building costs when
normalized for year of completion (taking cost inšation out of the analysis)
and location (rešecting the variation of building costs by locality).
Their work showed that themajor cost driver is the building program, that
is, what the building is designed to achieve. A simple branch library in the
suburbs might be fairly cheap to construct, but a downtown main library
will likely bemuchmore costly, on a dollars-per-square-foot basis.You can
Šnd a large big-city downtown library by a name architect that costs $500
per square foot, as well as one that serves the same function and costs only
$230 per square foot.
The Šgure below shows the results of the most recent Davis Langdon
study for ambulatory care facilities (one of Šve categories with enough
data from which to draw Šrm conclusions).32 The 2007 update included
additional project types and more cost data, all standardized to Sacramento,
California,mid-2006 costs. The conclusions of the study were unchanged:
certiŠed green buildings don’t cost any more than conventional
buildings, on a per-square-foot basis. What matters most: the building’s
design objectives.
Jerry Yudelson, Green Building A to Z, New Society Publisher