The Green Roundtable (copyright © Green Roundtable 2007) The Green Roundtable Making the Case for Green- Basic economics and
Jan 27, 2015
The Green Roundtable(copyright © Green Roundtable 2007)
The Green Roundtable
Making the Case for Green-Basic economics
and
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Consulting, education, trainingand strategic planning
to create healthy environments byintegrating principles of
sustainability into mainstreamplanning, design and construction.
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Objectives
- What are the key value-added propositions in greenbuilding? – i.e. selling green
- What are the basic economics of green building?
- How can we financially justify green?
- How can we sweeten the pot for our clients?
Answer the following questions:
- Why do green?
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Why do green….
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Some sad realities….
• Ozone depletion
• Air & water pollution
• Destruction of worlds forests & green spaces
• Species & biodiversity loss
• Acid rain
• Collapse of world’s fisheries
• Fresh water scarcity
• Topsoil loss; Soil contamination
Even if you don’t believe that the global warmingthreat is real, we are facing these certain realities:
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And if global warming is real…
• Crop failure on a massive scale
• Increases in drought frequency
• Deadly heat waves
• Rising sea levels/ coastal flooding
• Increased frequency & duration of storm activity
• Expansion of desert areas
• Increases in disease vectors
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On a more local or personal level…
• Rapidly rising energy costs
• Escalating prices on consumer goods
• Blackouts/ brownouts
• Water shortages
• Supply chain interruptions
• More frequent economic losses due to increased
storm intensity & flooding
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The United States produces 25% of globalgreenhouse gas emissions. Americans
produce twice as much per person than otherindustrialized nations
Some sobering facts…
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Water tables are now falling in countries thatcontain over half the world’s people
Some sobering facts…
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There are currently 1,243 EPA Superfundsites on the National Priorities List and 60
more proposed (as of 3/20/07)
Some sobering facts…
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The incidence of asthma has increaseddramatically over the last 25 years in the U.S.
and other industrialized nations.
Some sobering facts…
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The EPA estimates that indoor air can be upto five times as contaminated with VOCs as
outside air.
Some sobering facts…
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The EPA also reports that the airbornecontaminants found in our homes are threetimes more likely to cause cancer than the
pollutants outside
Some sobering facts…
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Cancer clusters have been identified insome more-affluent communities and have
been attributed to chemically-intensivelandscape management practices
Some sobering facts…
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A 15-year study in Oregon concluded thatwomen who work in the home have a 54%higher death rate from cancer than women
who work outside the home
Some sobering facts…
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China recently caught up to the United Statesin terms of overall energy consumption.
India isn’t far behind.
The U.S. & Canada are still the per capitaleaders by far
Some sobering facts…
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Some sobering facts…
The U.S., with 5% of the worlds population,consumes more than a third of it’s resourcesand over a quarter of its energy resources.
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Half of U.S. greenhouse gas emissions come frombuildings (construction/ operation)
Buildings account for nearly half of the total energyuse in the United States
Buildings represent the single largest energyconsumer in the U.S., followed by the transportation
sector
Where do buildings fit in…
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Additional housing sector facts…
According to HUD, if Americans can reducehome energy use by 10% over the next ten
years (a doable number!), it will be theenergy equivalent of 40 new power plants
(600 Mw) and the greenhouse gas equivalentof 25 million vehicles
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Additional housing sector facts…
There are more than 76 million residentialbuildings in the USA today
Estimates of residential energy consumptionas a proportion of the nation’s total energyload range from around 20 – 40%
From 2000 to 2005, winter heating costs fornatural gas increased by 115%, oil by 135%,and electricity by 18%
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Food for thought….
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Perhaps the most sobering fact of all…
It has been estimated that in order for the currentpopulation of the Earth to live at the same quality of life asthe industrialized nations, it would require the resources of
four ‘Earth equivalents’.
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This we know…
As a nation, the United States uses a disproportionateshare of the world’s natural resources
We live on a planet of finite natural resources
We are currently using those resources at anunsustainable rate
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This we know…
These conclusions are rooted in simple physics,chemistry, biology and economics
Energy prices are likely to trend in only one directionfor the foreseeable future! Most other resource pricesare likely to follow the same trend
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A solution:Green Building
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Why build green?
• Reduces the ecological footprint of the building
• Creates a safer and healthier indoor environment
• May improve property resale value
• Saves on utility expenses
• May increase affordability
• Typically results in a more durable, maintenance-free building
• Reduces our dependence on foreign oil
Building green:
• Provides security/ passive survivability
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• Economics- Reducing energy cost/ protecting thebottom line
• Health- Maintaining a safe and healthy environmentfor one’s family & oneself
• Personal impact- Addressing the greater good-minimizing environmental footprint
The three prime movers (in order):
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• The cool factor
• The “shiny metal objects” mentality
• Peer pressure
Some other motivators:
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Defining green building:
The effective and responsible integrationof the built environment into the naturalworld to protect natural resources andensure healthy and comfortable indoor
environments
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What makes it green?
• Low embodied energy (entire lifecycle)
• Minimizes impact on wildlife habitat, green space,waterways, etc
• Minimizes depletion of natural resources
• Poses minimal harm to humans during itsmanufacture, transport, installation, end-use ordisposal
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The quantity of energy required to manufacture, andsupply to the point of use including:
• Extraction• Transportation• Manufacturing
• Assembly• Installation• Some definitions also include:
Disassembly & Removal
What is embodied energy?
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Water Efficiency
Sustainable Sites
Energy & Atmosphere
Materials & Resources
Indoor Environmental Quality
Innovation & Design Process
The LEED Credit Categories
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Cornerstones of green building (structure itself)
Site Site
Site Site
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How green is it?
• The “no-build” option is always the greenest way
• Smaller is greener
• More efficient material resources use is better
• The more durable (in use) & maintenance free thebetter
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Selection criteria: Materials
• Efficiently uses energy & resources
• Contains high recycled material content
• Derived from rapidly renewable resources
• Can be reused/ recycled at the end of it’s useful life
• Can be down-cycled at the end of it’s useful life
• Biodegradable
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Post-Consumer vs. Pre-Consumeraka Post-Industrial
Recycled Content
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Defining green: Design resources
• Building America-http://www.eere.energy.gov/buildings/building_america/about.html
• Environmental Building News/ Greenspec-http://www.buildinggreen.com)
•http://www.austinenergy.com/Energy%20Efficiency/Programs/Green%20Building/Sourcebook/index.htm
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Measuring Green:Rating Systems
• LEED - www.usgbc.org
• Energy Star Homes- www.energystar.gov
• International Energy Conservation Code (IEEC)-http://www.iccsafe.org/
• HERS (http://www.energy.ca.gov/HERS)
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• Incorporate energy efficient design details
• Create a high-performance building envelope
• Employ water conservation strategies
• Employ natural daylighting techniques
• Use energy-efficient lighting, equipment & appliances
General strategies:
• Create comfortable & healthy indoor environments
• Minimize impact on building sites/ area
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Economics of green building
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Economic realities
Up front costs or first-costs of green buildingare often greater than conventional building
That doesn’t need to be the case!
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Additional construction costs
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Additional Pitfalls
• Uninformed & resistant code and municipal officials
• Products that ‘go away’
• Sourcing materials
• “Greening” small-scale projects
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Keys to success
• Careful design
• Using a team approach between owners,design professionals and code officials, andbringing everybody together early in theprocess
• Early planning
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Architects
BuildingOwners
Planners
Federal,Local,and StateGovernments
UtilityManagers
NonprofitLeaders
Engineers
BuildingTenants
PropertyManagers
ProductManufacturers
InteriorDesigners
CodeOfficials
LandscapeArchitects
FinancialPlanners
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• Start planning and design as early as possible
• Adopt a systems approach during the designphase- understand that virtually all systems/components affect the others
• Determine ‘lead time’ on products as early aspossible- this may allow some flexibility in shipping,will minimize project delays, etc.
• Design carefully and then finalize your design asearly in the process as possible- change orders canbe expensive!
• Make sure that you understand the properties ofthe materials and how to use them! Do yourhomework
Managing up-front costs (& expectations!)
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Managing up-front costs, continued
• Right-size systems- Don’t use rule of thumbapproaches
• Use a trade-off approach- offset increased cost inone product or system through savings in another
• Go green by incorporating no-cost design featuresand elements– The Low-hanging Fruit
• Offset increased first cost with rebates & incentives
• Match the project scale to the genuine space needs ofthe client!
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Underlying all:
ScaleScaleScale
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The average size of a U.S. single-familyhouse has increased by 33% since 1975. At
the same time average family size hasdecreased.
Consider this:
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• Take advantage of marginal cost of installing higherquality materials- e.g. adding thicker insulation(reduces life-cycle cost, but maybe not up front cost)
Managing up-front costs, continued
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Justifying increased up-front costs
Making the case for reduced Life-Cycle Cost or TotalCost of Ownership (TCO):
• Green buildings usually use less energy to operatethan their conventional counterparts
• Green buildings are typically more durable &maintenance-free due to the application of soundprinciples of building science
• There are typically additional benefits that help towarrant the increased cost
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The trump card
A University of Michigan study demonstrated thatgreater than 90% of the embodied energy in a home
is attributable to operating energy
Reduce operating energy and potentially reduceTCO significantly
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Low-hanging Fruit(A sampling)
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Using the site
• Take advantage of existing vegetation if possible-deciduous trees for shading; coniferous trees aswind breaks
• Site structure on south-facing slope for maximumsolar gain; take advantage of wind & solar resources
• Use natural terrain features to protect structure fromcold winter winds
• Site structure downwind from lakes, ponds, wetlandsfor natural cooling
• Take advantage of hills that funnel breezes
• Use earth-berming if topography permits
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Building orientation/ layout
• Orient structure along East-West axis; i.e. long sidefacing south
• Minimize glazing area on north, northeast & west-facing walls
• Maximize glazing on south-facing walls tomaximize winter solar gains
• Incorporate buffer spaces in structure- closets alongoutside walls, vestibules, enclosed porches, etc.
• Minimize surface area-to-volume ratio; avoidcomplicated designs w/ many intersecting planes
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Sustainable sites: Low-hanging fruit
• Minimize heat urban island effect by using light-colored pavement
• Use landscape features that allow stormwater topercolate into soil- e.g. bioswales
• Manage stormwater by using pervious paving
• Use water conserving landscape maintenancepractices– Xeriscaping, native plantings, etc.
• In general, minimize site disturbance
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Common name Botanical Name HeightAmur Maple Acer ginnala 20'-25'
Austrian Pine Pinus nigra 50'
Japanese Black Pine Pinus thunbergii 6-10'
Cornelian Cherry Cornus Mas 20-25'
London Plane Platanus x acerifolia 50'
White Oak Quercus alba 50'
Low-water trees:
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Common name Botanical Name HeightBroom Cytisus scoparius 5-6'
Flowering Quince Chaenomeles specoisa 6'-10'
Junipers Juniperus sp. 2'-9'
Cinquefoil Potentilla 3'-4'
Butterfly Bush Buddleia davidii 6-10'
Rose-of-Sharon Hibiscus syriacus Diana 6-8'
Winterberry Ilex verticillata 8-10'
Mugo Pine(dwarf) Pinus mugo 3-4'
Low-water shrubs:
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Common name Botanical Name HeightBearberry Arctostaphylos uva-ursi 6-8"
Creeping Lilly-turf Liriope spicata 6-8"
Violets Viola sp.. 6-8"
Snow-in-Summer Cerastium tomentosum 6-8"
Low-water groundcovers:
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Common name Botanical Name HeightNew England Aster Aster Novae-angliae 15-30"
CommonBlanketflower Gaillardia aristata 24-36"
Moonbeam Coreopsis verticillata 24-36"
Purple Coneflower Echinacea purpurea 24-36"
Low-water perennials:
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Materials: Low-hanging fruit
• Employ advanced framing techniques
• Keep it small!
• Use structure as finish
• Use salvaged/ surplus materials
• Use low-VOC paints, sealants & adhesives
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Design strategies: Advanced Framing
• Saves on labor cost since fewer “sticks” installed
• Saves on framing lumber expense
• Reduces lumber disposal cost/ impact
• Savings estimates range to 20% of overall framingexpense
• Improves thermal envelope of building– moreplaces to insulate!
• Can offset the cost of using FSC-certified lumber
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Advanced framing & efficiency
• Provides more room for insulation!
• Reduces bridging heat loss
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Advanced Framing
• “Right-sized” headers; insulated, engineered headers
• Features 2 x 6 studs on 24” centers
• Jack studs eliminated at window openings
• No headers in non-load bearing partitions
• Single top plate if trusses/ roof rafters placeddirectly over wall studs
• Open corner framing (2-stud corners)
• Ladders at T-intersections
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Durability: Low-hanging fruit
• Minimize roof penetrations
• Maintain proper grading & ground clearances
• Incorporate overhanging roofs
• Keep vegetation away from structure
• Use well-designed wall sections
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Energy: Low-hanging fruit
• Right-size systems
• Use structured plumbing & PEX piping
• Move ductwork into conditioned space
• Spec Energy Star
• Use zone lighting
• Use natural daylighting strategies
• Use zoned heating
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Cooling
Use ceiling fans w/ cathedral or high ceilings toeliminate temperature stratification (both heating andcooling season)
Shade air conditioner and heat pump condensers w/vegetation or artificial shading (be careful w/ deciduousvegetation) if you have to locate on sunny side
Locate AC/ heat pump condensers on N or NE orNW side out of direct sun!
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Cooling
Use deciduous vegetation on south, SW and westsides of structure for summer shading; use vines ontrellises too
Use coniferous (evergreen) trees/ shrubs to redirectbreezes/ wind
Install awnings, overhangs and other shadingstructures, such as pergolas
Make sure attic space is well vented
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Take advantage of prevailing winds for natural cooling
Maximize cross-ventilation
Use building elements to funnel winds (e.g. casementwindows)
Use light-colored shingles or roof membrane on very lowpitched or flat roofs
Cooling
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A sampling of strategies &approaches for reducing life-
cycle cost or TCO
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Green Practice:Water conservation
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Order a free water saving kit at:www.mwra.com/04water/html/watsense.htm
MWRAA water conservation resource
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Water conservation
• Use low-flow showerheads & faucet aerators
• Collect rainwater in rain barrels for landscapeirrigation
• Incorporate graywater systems
• Use demand pumps in supply system
• Use dual-flush or composting toilets; waterlessurinals
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The Portland Group- Splash Showroom244 Needham St.Newton, MA 02164617.332.6662
Coroma Dual-Flush Toilet Source
See: http://www.caromausa.com/products/toilets.htm
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Green Systems:Gray water
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Gray water
• Collected from drain-waste-vent system other thantoilets & kitchen sinks with garbage diposals (“Blackwater”)
• May be difficult to get local code approval
• Generally used for flushing toilets, landscapeirrigation & other non-potable, utility purposes
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http://www.gaiam.com/product/eco-home-outdoor/energy-efficient-climate-control/energy-saving-tools/toilet+lid+sink.do
Gray water: A direct approach
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Rainwater collection
• For 1000 sq ft roof area, 15 – 25,000 gallons ofrainwater can be collected annually in Eastern states
• Using rainwater helps to maintain aquifers and publicwater supplies at adequate levels
• Combined with drip-irrigation systems, collectedrainwater can keep landscaping vibrant even duringdrought conditions
• Rainwater does not contain minerals, so it ispotentially better for use as laundry/ wash water
• Rainwater does not contain chlorine so it is better forplants, garden ponds, etc.
• Rainwater is free, and inexpensive to collect & store!
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http://www.cleanairgardening.com/33galrainbar.html
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Xeriscaping (low-water-landscaping)
• Two major aspects:-Making maximum use of available precipitation-Selecting species with low water requirements
• Use drip irrigation & soaker hoses
• Use mulches
• Create water retention landscape features
• Group plants
• Use native plantings, they are better suited to naturalrainfall patterns
• Use plantings to create windbreaks & shade toprotect from drying winds and sun
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Drip emitters
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Soaker Hose
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Energy ConservingDesign Strategies (a sampling)
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Design Strategies: Thermal mass
Thermal mass:
• Can be used to store heat in winter
• Can help to moderate temperatures year-round
• Key element in passive solar design
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Thermal mass: How to incorporate
• Masonry veneers on exterior walls
• Masonry finishes on interior walls & floors
• Fireplaces, chimneys & interior masonry features
• Thickened walls- e.g.double drywall layer
• Green roofs
• Cob & masonry construction
• Water features/ elements
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Thermal mass: additional benefits
• Acoustic comfort
• Increased structural integrity in some situations
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Design Strategies: Green roofs
• Properly designed, can pay for themselves in 10 –15 years via reduced energy cost
• Especially effective in reducing cooling costs
• By some estimates, can reduce cooling costs by upto 30% in single-story structures
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Green roofs: additional benefits
• Can provide stormwater management
• Reduce urban heat islands
• Help to minimize global warming
• May extend the life of your roof
• Provides green space & wildlife habitat
• Improves acoustic comfort
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Design Strategies: Passive solar
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Passive solar
Basic requirements:
• Collect it…
• Retain it…
• Store it…
• Distribute it…
Free heat from the sun; ‘greenhouse effect’ (goodkind!); good southern exposure/ solar aperture needed
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5 Major elements ofPassive Solar
• Aperture/ Collector (glazing)
• Absorber
• Distribution
• Thermal storage (mass)
• Control
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Requirements
• Glazing area to collect sunlight- 7% rule- So.-facing
• Window insulating system (and good buildingenvelope insulation) to keep heat in at night
• Thermal mass- needed to store heat if net windowarea is more than 7% of total floor area
• Shading—vegetation (deciduous), or shadingstructures like awnings, roof overhangs andpergolas, to prevent overheating during warmer mos.
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Requirements,cont.
• Distribution system—to remove excess heat toother parts of house where it may be needed inwinter
• Ventilation system—to remove excess heat tooutside during warm weather
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Passive Solar Rules-of-Thumb
• Orientation of aperture area should be within 30degrees of true south
• Aperture should ideally be shade-free from 9am –3pm
• Direct gain systems are most common and easiestto integrate into most designs; glazing should notexceed 12% of building floor area
• South-facing glass should be vertical and shouldhave some kind of overhanging to shade fromsummer sun
• Thermal mass can help to moderate temperature insummer as well as store heat in winter
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Passive Solar Rules-of-Thumb
• Skylights should be avoided on all but north andnortheast-facing roof surfaces, as they can otherwisecontribute to overheating in the summer, and won’tprovide appreciable gains in the winter due to lowangle of sun
• Deciduous trees can provide good summershading, but should not be located too close tohouse/ sunspace, as trunk/ branches may providetoo much shade in winter
• In sunspaces, may need powered ventilation tominimize summer overheating
• Well designed passive solar can provide 5 –25% ofspace heating needs with no added cost
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Angled glass may not be the best configuration,especially without an overhang!
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Skylights may contribute to summer overheatingand winter heat loss.
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Frost-protected Shallow Foundations
• Improves thermal performance
• Reduce excavating expense
• Reduce site impact
• Reduce material expense
• Note: Local code officials may be resistant toapproving this foundation system
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Design Strategies: Natural daylighting
• Can reduce lighting loads and cooling loads
• Residential systems typically consist of skylights,clerestory windows or tubular daylighting devices(TDD’s; “sun tubes” or “light tubes”)
• Improves indoor environmental quality
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Design Strategies: Natural daylighting
• Skylights in south, southwest and west-facing roofscan contribute to summer overheating
• Skylights in more north-facing roof surfaces cancontribute more light on cloudy days
• TDDs may contribute less to overheating
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Sky tube (TDD)
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Natural daylighting
• Light-colored walls reflect light deeper into structure
• Light shelves can serve the same purpose, andaccomplish this w/o excessive glare; they provideshading as well
• Combine daylighting strategies with photo-resistorcontrolled lights to avoid excessive lighting duringdaytime
• Wide windowsills/ shelves can reflect light as well,but may contribute to glare
• Landscape features can be utilized for reflectinglight into interior as well (paved surfaces, waterfeatures, etc)
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Light shelves shade windowwhile providing natural daylightvia light reflected from topsurface
Can help light to penetratedeeper into structure
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Suggested Room SurfaceReflectances:Ceilings: > 80%Walls: 50%-70%Floors: 20%-40%Furnishings: 25%-45%
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RADIANCE is a lighting anddaylighting visualization tooldeveloped by LBNL and is availableover the web:http://radsite.lbl.gov/radiance/
Lighting & Daylighting Analysis
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Green Practice:Improving the Building Envelope
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Building envelope, definition
All of the elements of a building that separate andisolate the outdoor environment from the indoorenvironment. This may include walls and wall finishes,roofs and roof finishes, doors, windows, skylights andbasement floors and walls.
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Key Principle- Saving home energy
As a general rule, for the average home/homeowner, the greatest energy savings will beachieved through managing the demand side of
the equation, rather than the supply side.
In other words, you’ll get better bang for your buckthrough energy conservation measures, like insulating
& minimizing air infiltration, than incorporatingexpensive renewable energy systems such as wind
and solar.
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An exception:
Exceptions to this may include passive solar, andsituations where you qualify for a substantial rebateand/or credit for other renewable energy systems(keep in mind the embodied energy of systemsthough!)
There are other compelling reasons to performupgrades like this, such as reduced reliance onforeign energy resources, promotion of renewableenergy & local industry, passive survivability, etc.
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Preventing heat loss
• Air seal (prevent infiltration)
• Best bang for buck through air sealing! Begin here!
• Insulate
• Use landscape features- vegetative shields, etc.
• Address lifestyle issues
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Building envelope, functions
• Protect structural elements and interior of structurefrom weather, esp. moisture
• Help to maintain proper thermal regime withinstructure
• Help to maintain proper humidity regime withinstructure
• Prevent infiltration of outside air and contaminants
• Acoustically isolate interior of structure from outsidenoise
• In essence, act as ‘membrane’ for the structure
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Building envelope failure
• External water leaks leading to:-Damaged structural elements-Damaged interior finishes-Insulation failure-Damaged interior furnishings and appliances-Mold problems
• Air leaks leading to:-Infiltration of unconditioned air/ Drafts-Direct escape of conditioned air to outside-Infiltration of outdoor contaminants
• Excessive accumulation of interior moisture in wallcavities causing structural/ insulation failure & mold
• Excessive heat transfer from inside to outside
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Building envelope components
• Exterior finish- wood siding, vinyl siding, brick, etc.
• Weather membrane/ air barrier/ drainage plane-building paper, Tyvek, Typar, etc.
• Exterior sheathing- usually plywood or OSB
• Wall/ ceiling cavities (inc. structural members &insulation)
• Vapor retarders/ barriers
• Interior wall finish
• Doors & windows
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Codes and standards
• Sixth edition of MA building code was officiallysuperseded by 7th edition as of January 1st, 2008
• New MA energy code based on 2006 InternationalEnergy Conservation Code; more stringent
• Better to follow Energy Star Homes or HERSguidelines for maximum energy efficiency and codecompliance (see resources slide)
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Minimizing air infiltration(sealing building envelope)
• Min .35 Air changes per hour (ACH) for goodventilation; max .50 for energy efficiency (EnergyStar)
• Openings to attic spaces are some of worst offenders
• Seal obvious openings- pipe penetrations, atticscuttles, electrical receptacles, recessed lights, etc.
• Any place where two building planes meet is goodcandidate for air sealing
• For additions/ new construction, use exterior airbarrier to minimize infiltration
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Housewrap tominimize airinfiltration &protect frommoisture
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Blower doortest tomeasure airleakage
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Air leakage pathways
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Air leakage proportion through various pathways
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Attic hatches/ scuttles are a major leakage pathway
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A commercial solution for attic openings
See also www.efi.org
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Insulate header/ rim joists w/ rigid foam & expanding foam
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Seal joints between intersecting planes w/ expanding foam
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Fireplaces are usually NOT an effective heating appliance!They lead to excessive heat loss via drafts up chimney.
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Air sealing, online productsources
• efi.org
• conservationtechnology.com
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Insulating
• Resistance to heat flow (insulating ability) measuredin R-value; not important to know how this is derived;mainly need to know that it’s a relative scale ofeffectiveness, and the higher the R value, the betterthe insulating value
• Code represents absolute minimum; newer codehas more stringent requirements; tied to window area;R-49 ceiling, R-21 walls, R-30 floors, R-13 basementtypical
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Insulating guidelines
• Remember that if you use A/C you are minimizingcooling expense by buttoning up your house as wellas heating expense
• Go for low-hanging fruit- e.g. add more atticinsulation first if it is accessible and is not wellinsulated; Don’t forget the basement!
• Look for additional opportunities to insulate (otherthan typical wall/ ceiling cavity insulation)
• Try to eliminate bridging (perimeter) heat lossthrough structural elements, as it greatly reducesoverall insulation effectiveness
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Basement/ foundation insulation often overlooked
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Bridging heat loss
• Eliminate with:-Double wall construction (very expensive!)-Foam skin-Cross-banding attic batt insulation
• Conductive heat loss through structural members
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Bridging heat loss- snow melts over roof rafters
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Bridging heat loss caused wall-staining over structural members
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Bridgingheatloss throughsill plates
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Layer of foamminimizes bridgingloss through sill;top of concretefoundation wallwill also receivelayer of foam
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Thermograph to check heat loss through walls (insulation effectiveness)
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Windows
• ‘Low-e’ coating reflects heat back into structure
• Performance measured in “U-value”; inverse of R-value; measure of material’s ability to conduct heat;the lower the U-value, the better
• Double-glazed, argon filled preferred; Diminishingreturns with triple glazing
• Typical heat loss through windows about 20%
• Look for U-value of .35 or less
• Always look for Energy Star & NFRC labels(energystar.gov; nfrc.org)
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NFRC Label
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Windows
• Provide nighttime insulation
• Used ‘tuned” glazing strategies
• Incorporate/ install overhangs & other shadingdevices where appropriate
• E.g., Use windows w/ low SHGC on west-facingwindows; high SHGC on south-facing
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Cellular insulating window shades can provide nighttime insulation
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Side tracks make them easier to operateand reduce air leakage around edges
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Green Practice:HVAC/ Plumbing
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HVAC & Plumbing Systems
• “Right-size” systems using analysis tools (Manual J)rather than rule-of-thumb methods; a right-sizedsystem can be up to 40% smaller than aconventionally-sized system
• Use demand pumps in DHW supply system(gothotwater.com)
• Use heat recovery devices on DWV pipes(gfxtechnology.com)
• Use instantaneous hot water heaters (tankless)
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Tankless water heaters
• Examples of brands: Rinnai, Noritz, Takagi
• Gas-fired typically more responsive and can provideneeded capacity more effectively
• Cost more than standard water heaters but last longer
• More choices as to location/ placement
• Direct-venting; e.g. can exhaust through wall
• Save energy by eliminating standing heat loss (vs.conventional tank-style water heater); estimated savings24 – 34%
• Look for min. flow rates of 0.3 – 0.5 gal./min.
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High-efficiency heating
• Boilers tend to have higher AFUE than furnaces
• Make sure heating systems have Annual FuelUtilization Efficiency (AFUE) of at least 83% for oil-fired and 90% for gas-fired, and Seasonal EnergyEfficiency Rating (SEER) of at least 13 for coolingsystems
• Closed-cycle, condensing-type boilers and furnacesare more efficient; they extract additional heat fromwarm flue gases
• These systems often don’t need conventional flue pipe,they can side vent, but they require a dedicatedcombustion air source (coaxial flue pipe)
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Ductwork
• Seal ducts; use duct mastic for this if possible,otherwise make sure duct tape is UL listed
• Insulate ducts in unconditioned spaces; for cooling(A/C) ductwork, make sure insulation has externalvapor barrier to minimize condensation
• When insulating ducts in unconditioned basement,you may make basement too cold; insulatebasement walls instead
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Lighting
• Use solar landscape lights
• Use motion sensor outdoor lights
• Put timer switches on bathroom fans
• Use dimmer switches & occupancy sensors
• Spec CFL’s & fluorescents
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Appliances
• Buy Energy Star!
• Specify horizontal axis washing machines
• Specify dishwashers w/ booster heater
• Don’t specify oversized AC equipment!
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http://www.energystar.gov/index.cfm?c=dishwash.pr_dishwashershttp://www.energystar.gov/index.cfm?c=clotheswash.pr_clothes_washershttp://www.energystar.gov/index.cfm?c=boilers.pr_boilers
Energy Star savings calculators
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A general list of tools offered by the U.S. Departmentof Energy are available over the web at:http://www.eere.energy.gov/buildings/tools_directory/subjects.cfm/pagename=subjects/pagename_menu=whole_building_analysis/pagename_submenu=load_calculation
General analysis tools
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Sweetening the pot
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Rebates and incentives
• Energy efficient mortgages
• MA state renewable energy tax credit
• Mass Technology Collaborative’s CommonwealthSolar Initiative
• MA state sales tax exemption
• Federal Energy Policy Act of 2005
• See DSIRE database (Database of StateIncentives for Renewables & Efficiency):http://www.dsireusa.org/
• Utility incentives
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Federal Energy Policy Act of 2005
Examples:
• Energy Star windows/ skylights: 10% of cost up to$200 for all windows
• Exterior/ Storm doors: 10% of cost up to $500
• Insulation: 10% up to $500
• Geothermal heat pump: $300
• http://www.energy.gov/taxbreaks.htm
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Energy Efficient Mortgages
• Remodelers/ Refinancers:-Owner gets all the EEM benefits without moving.-Make improvements which will actually save
money.-Increase the potential resale value .
• Allows you to increase your debt-to-income ratio
• Home Energy Rating System (HERS) report mustindicate that home will save money as a result of theimprovements- http://www.energy.ca.gov/HERS/;http://www.energyratings.org/
• For more info:http://www.pueblo.gsa.gov/cic_text/housing/energy_mort/energy-mortgage.htm
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MA Renewables Tax Credit
• Solar Water Heat, Solar Space Heat, Photovoltaics,Wind
• 15% of cost up to $1000
• Excess credit may be carried forward three years
• http://www.state.ma.us/doer/programs/renew/renew.htm#taxcred
• Personal tax credit
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MA State Sales Tax Exemption
• 100% of sales tax exempt; no maximum
• Solar Water Heat, Solar Space Heat, Photovoltaics,Wind, Geothermal Heat Pumps
• http://www.state.ma.us/doer/programs/renew/renew.htm#taxcred
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MTC Small Renewables Initiative
• Rebates up to $50,000
• PV, wind, microhydro
• See http://www.masstech.org
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MTC Commonwealth Solar
• $68 M Funding
•http://www.masstech.org/renewableenergy/commonwealth_solar/index.html
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•High-efficiency space heating equipment
•High-efficiency indirect water heating equipment
•ENERGY STAR® qualified windows
•ENERGY STAR® qualified thermostats
•ENERGY STAR® qualified central air conditioning
•ENERGY STAR® air source heat pump systems
Typical utility rebates
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GRT: www.greenroundtable.orgBuilding Green: www.buildinggreen.comEnergy Star: www.energystar.govCharles River Watershed: www.crwa.orgUS Green Building Council: www.usgbc.orgRenewable Energy: www.nrel.govUS DOE: www.eere.energy.gov/buildings/EPA: www.epa.gov/ne/greenbuildings
Residential Green Building Guide:A Web Source Book for New Englandwww.epa.gov/ne/greenbuildings
NAHB: Model Green Home Building Guidelines:www.nahb.org
Resources
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• Upcoming workshops• Reference library• Samples library• Cyber Lounge• Online resources at nexusboston.com (in the
pipeline)• Local green building community
And don’t forget about NEXUS!
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Local Resources
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The Green Roundtable, Inc. (GRT) is an independent non-profitorganization whose mission is to mainstream green building andsustainable design and become obsolete. We work toward this goal bypromoting and supporting healthy and environmentally integrated buildingprojects through strategic outreach, education, policy advocacy andtechnical assistance.
617-374-3740
www.nexusboston.com38 Chauncy Street, Boston
Located in downtown Boston, NEXUSwelcomes all to come ask questions,research topics, and attend tours andevents on green building and sustainabledesign innovation.
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