9. Why Build Green

8/8/2019 9. Why Build Green....

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proach capacity, solidwaste disposal becomes ever

more challenging in Santa CruzCounty. Minimizing the ow ofwaste to the landll is criticalto extending its useful life. Thisbooklet highlights materials andtechniques which help reduceConstruction and Demolitionwaste, which accounts for over20% of total waste volume.

In addition to environmen-tal benets, waste reduction di-

rectly contributes to our nancialwell-being. When we extendthe life of the landll and delaythe expense of a replacementsolution, taxpayers save money.Designing to use less materialand minimizing constructionwaste reduces the material costof a project, saving money forhomeowners, contractors, anddevelopers. Using salvaged,recycled, and remanufacturedproducts helps the environ-ment, and local manufacturing

.The innovative practice of de-construction diverts waste from

the landll, and surprisingly canreduce costs to building ownersthrough available tax incentivesand by reducing material re-quirements.

Eliminating or minimizingwaste is one important elementof green building, a broadset of design and constructionpractices that provide healthyplaces to live and work while

reducing negative impacts tothe environment. Keep in mindthat this booklet highlights onlya small sample of greener mate-rials. Every option has strengthsand weaknesses to consider, andno single material is ideal for allapplications. But do not let thepursuit of perfection stand in theway of doing something posi-tive for occupants, the environ-ment, the community, and oureconomy.

IntroductionKey to Benets

Deconstruction

Passive Solar Design

Xeriscape

Fly Ash Concrete

Pervious Concrete

Insulated Structural Systems

Earthen Building Materials

Straw Bale Construction

Advanced Framing Techniques

FSC Certied Wood

Engineered Lumber

Oriented Strand Board (OSB)

Recycled Plastic Lumber

Reclaimed Wood Siding

Fiber Cement Siding

Metal Roong

Recycled-Content Roong

50-year Composition RoongRecycled Cotton Insulation

Spray Foam Insulation

High-Efciency Windows

Recycled-Content GypsumWall Board

Homasote

Recycled-Content Tile

Reclaimed Hardwood

Bamboo

Recycled-Content CarpetLinoleum Flooring

Cork Flooring

Zero-VOC Paint

Natural Wallcovering

High-Efciency Appliances

Solar Photovoltaics

Radiant Hydronic Heating

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Reduces air or water pollution

Conserves natural resources andecosystems

Promotes healthy indoor air quality

Increases efciency or conservesenergy

Minimizes waste through reuse,recycling, and/or material reduction

KEY TO ENVIRONMENTAL BENEFITS

CONTENTS

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Deconstruction/Construction &Demolition Recycling

Deconstruction is thedismantling of a buildingto preserve the useful valueof its component materials.Consider requesting bidsto deconstruct rather

than demolishing; thecombination of tax breaks,new tools, and increasinglocal expertise are makingit easier to keep materialsout of the landll, andmoney in owners wallets.

PROS: Reduces or eliminates unnecessarywaste extends the life of our landlland reduces the need for newmaterials as well as material costs. Older structures may containhardwoods and dimensional lumberthat are superior in size or quality tovirgin materials. The tax deduction from donatingdeconstructed materials to a non-prot organization can be morevaluable than the additional laborcost.CONS: Deconstruction takes longer andinitially cost more than demolition,but can reduce the overall project

cost. Not all contractors are familiarwith the techniques, tools, and taxbreaks.

Passive Solar Design

Passive solar design is aneffective method of heatingand cooling throughutilization of sunlight.Proper building orientation,thermal mass, and insulationare specied in conjunction

with careful placementof windows and shading.Thermal mass absorbs heat

during the day and radiates it backinto the room at night. The effect isa quiet, comfortable, energy efcientspace with stable year-roundtemperatures.PROS: At little or no cost, passive solardesign can easily be designed intonew construction, and can beretrotted into existing buildings insome cases. It pays dividends over the life ofthe building through substantiallyreduced or eliminated heating andcooling costs. Indoor air quality improvedthrough elimination of forced airsystems.CONS: Not all building professionalsare experienced with passive solardesign.

Retrotting is rarely as effective asinitially designing for this method. Sites with limited southernexposure may be less suitable.

Xeriscape

Xeriscape is landscapingdesigned to reduce theresources needed fomaintenance (most notablywater,) and the wastethe landscape producesSuccessful xeriscapes match

local resources, soil, andclimate with the aestheticgoals of the owner, and

incorporate native California planspecies as well as exotic plantssuited to our climate.PROS: Reduces irrigation, saving moneyfor the owner and conserving for oucommon water needs. Reduces maintenance and greenwaste, saving time and money. Eliminates or reduces theexpense of piping and trenching forirrigation. Requires less fertilizer, reducingpollution of air and water. May allow collected rainwater tobe concentrated on edible plants.CONS: Requires research (or at least askingquestions at the garden store). Existing landscapes usually requiresome plant replacement to maximizewater savings.

Fly Ash ConcreteStrong, inexpensive, du-rable, and adaptable, con-crete is the most widelyused construction mate-rial in the U.S. Its envi-ronmental impacts includehabitat disturbance fromextraction, and heavy en-ergy use/pollution from themanufacture and shippingof cement. Manufacture o

portland cement accountsfor 90% of the embodied

energy of concrete, but y ash, awaste product diverted from coapower plants, can replace more than50% of the cement and actually im-prove performance.PROS: Reduces waste, pollution, andgreenhouse gas emissions. Performs as well as or better thanstandard concrete, often at no addi-

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Reusable materials are sorted as they are removed from this Santa Cruz deconstruction site.Photo courtesy of Deconstruction Industries, Inc.


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tional material cost. Increasing popularity has made itreadily available.CONS: Curing time may be extended. Determining the best mix for anapplication requires some research. Not all building professionals arefamiliar with y ash concrete mixes.

Pervious Concrete

Up to 75% of urbansurface area is covered byimpermeable pavement,which inhibits groundwaterrecharge, contributes toerosion and ooding,conveys pollution to local

waters, and increases the complexityand expense of storm watertreatment. Pervious paving contains

voids that allow water to percolatethrough to the base materials below.PROS: Reduces peak storm water owand water pollution and promotesgroundwater recharge. May incorporate recycledaggregate and y ash, reducingwaste and embodied energy. Compressive strength (4000 psi) issuitable for parking and access. Reduces problems with tree roots;encourages roots to grow deeper. Enhanced heat exchange withthe underlying soil can decreasesummer ambient air temperature by2-4F.CONS: May require vacuuming every fewyears to keep the voids open.

Insulated Structural Systems

Insulated structural systemsintegrate a buildings

structure and insulation intoa single component. Rastraand Insulated ConcreteForms (ICFs) consist of ahollow shell that acts both

as insulation and a permanent formfor concrete. Structural InsulatedPanels (SIPs) are factory-built walls/roof panels consisting of rigid foaminsulation sandwiched between twolayers of structural facing (typicallyOSB).

PROS: Reduced construction waste panels are pre-cut at the factory. Reduced or eliminated structuralwood use. Superior structural, thermal, andacoustic performance. Excellent re resistance(particularly in the case of Rastra).

Rapid construction, some aresuitable for do-it-yourself assembly.CONS: Not all designers or builders arefamiliar with these systems. Higher material costs -thoughtypically offset by reduced laborcost and accelerated constructionschedules.

Earthen Building Materials

Beautiful, sculptural anddurable, common earthenbuilding materials include:adobe bricks - made fromclay, sand, and straw;rammed earth- compressedwith y ash and/or bersfor stabilization; and cob- clay, sand and straw thatis stacked and shaped whilewet.PROS: Plentiful materials,

producing little or nowaste, requiring minimalenergy use (if materials are

extracted locally), which can bepulverized back into soil at the endof its useful life. Historically very durable. Theadobe Santa Cruz Mission, forexample, is over 200 years old. Provides excellent thermalmass for passive solar buildings,maintaining stable, comfortableindoor temperatures year round.

CONS: Thick walls may comprise a highpercentage of oor area on smallsite. Construction is labor-intensive. Multi-story and cob structuresrequire post-and-beam designs.

Straw Bale Construction

In straw bale constructioncompressed bales ostraw are stacked andcovered by plaster, eitheas ll for a wall (non-loadbearing) or as a structura

component (load bearing)Both categories diveragricultural waste fromburning or the landll, anduse much less wood and/oconcrete than conventionaconstruction.PROS: Straw is a plentiful waste

product and rapidly renewable. Provides excellent thermal andacoustical insulation.

The small quantity of constructionwaste generated is compostable. Walls are more resistant to remold, and vermin than conventionaconstruction. Reduced material cost, andpotential for lower labor cost.CONS: Finished straw bale walls are 18to 28 thick, potentially consumingsignicant space on a small lot.

May require research or specialtycontractor to construct.

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Most Structural Insulated Panels (SIPs) areproduced with EPS foam core laminatedbetween OSB sheathing. Factory built to customspecications, they are quick to assemble andhave excellent energy performance. Photo courtesy of Insulspan.


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Advanced framing techniquesreduce wood usage, minimizelabor costs and increase the areaavailable for insulation.

Advanced Framing Techniques

Advanced framing tech-niques reduce the quantityof wood required by up to20% over conventionalframing, and include suchmethods as: framing with

2x6 studs on 24 centers (inlieu of 2x4s on 16centers);stacking roof rafters directlyover studs; framed-in andinsulated headers in lieu ofsolid dimensional lumber;

use of prefabricated trusses or wall-units.PROS: Widely accepted by buildingdepartments and code ofcials. Deeper wall cavity allows addi-

tional insulation. The use of fewerstuds reduces thermal bridging,improving the efcacy of insulation. Reduces labor, waste and materialcosts while saving natural resources.CONS: Buildings must be designed for2x6 construction, requiring consid-eration early in the design process. Contractors may not be familiarwith some techniques, requir-ing extra training or consulta-

tion with experienced installers. Installing drywall clips can bemore labor-intensive than nailers.

FSC Certied Wood

Wood is a renewable re-source that requires rela-tively little energy to pro-cess. However, logging,

milling, transport, and disposal ofwood have substantial environ-

mental costs. These impacts can bereduced through minimizing wooduse (substitution with alternatematerials, reuse, design to reducewaste/redundancy), and by buildingwith certied wood. Forest Steward-ship Council (FSC) certication is awidely recognized and respectedstandard for responsible forest man-agement.PROS:

Rough and nish materials areavailable. FSC lumber is available from sev-eral local suppliers (some harvesttheir wood locally, reducing theenvironmental effects of transporta-tion).CONS: Materials costs are up to 10%higher than non-certied lumber. Pre-ordering may be necessary;

selection of dimensional lumberand quantities in stock are variable.

Engineered Lumber

Engineered lumber con-sists of oriented strips ofwood pressed togethewith a binding agent. Thestrength and durability oengineered lumber allows ito displace the use of large

mature timber. Using engineeredlumber instead of large dimensionrafters, joists, trusses and posts cansave money and reduce total wooduse in a construction project by asmuch as 35%.PROS: Longer, stronger, straighter, moredurable, and lighter than compa-rable solid lumber. Wider spacing of members in-creases the insulated portion owalls, reducing heat loss through thebuilding frame. Widely available and cost-effec-tive.CONS: Uses petrochemical-based bind-ers, generally phenolic formalde-hyde (which is vastly preferable tourea formaldehyde, however). FSC certied options are very lim-ited.

Oriented Strand Board (OSB)

Oriented strand board(OSB), an alternative toplywood sheathing, consistsof layers of wood bitsoriented for strength andpressed together with a glue(or binder). In comparison

to plywood sheathing, OSB usesless wood and relies upon smallerfaster growing trees. OSB with anMDI binder (diphenyl methanediisocyanate) is preferable to the

more common phenol formaldehydeglue, because MDI does not emiformaldehyde or VOCs. (Notethat formaldehyde emissionsfrom particleboard cabinets andfurnishings are far more likely to bea concern because OSB is typicallysealed in the wall or roof cavity.)PROS: Made from more rapidly renewableresources than plywood. Typically less expensive thanplywood.

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The FSC Logoidenties prod-ucts which con-tain wood fromwell managedforests certiedin accordancethe the rules ofthe Forest Stew-ardship Council(FSC).

1996 Forest Stewardship Council

FSC-US-0050

Illustration Building Science Corporation. Used with permission.


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CONS: Integrity can diminish with repeatedand extended moisture exposure. As with any wood product, properroof and wall assembly and nishingis essential for longevity. FSC certied options are verylimited.

Recycled Plastic LumberPolyethylene grocery bags,soda bottles, and palletwrap are remanufacturedinto dimensional lumberproducts. These may bepure plastic, or incorporatewood bers to form a

composite. Both are widely availablealternatives to wood for outdoorprojects, such as decks.PROS: Very durable, immune to insectsand rot, and UV resistant. High recycled content, reducingwaste and embodied energy. Reduces logging of mature trees,particularly redwoods. Requires virtually no maintenance,eliminating the repeated use ofsolvent-based sealants commonlyapplied to wood.CONS: Composites are not biodegradable

or currently recyclable, thoughremanufacturing options may bedeveloped. Structural options are limited. Higher rst cost, but lower life-cycle cost.

Reclaimed Wood Siding

Wood siding can often besalvaged and refurbished.In the process, virgin wood

use is reduced, a wasteis kept in productive useand out of the landll, andowners can save money.

PROS: Salvaged wood siding can offerunsurpassed beauty and qualitythat may no longer be available,frequently at a lower cost than newsiding. Reduces waste sent to the landll. Reduces virgin wood usage.

CONS: Finding salvaged siding in thedesired style and quantity usuallyrequires research, exibility, andpatience. Older painted wood should betested for lead contamination. Leadcontaminated wood should notbe sanded, and should either be

professionally treated or disposed ofproperly.

Metal Roong

Metal roong is typicallyextremely durable, andmany materials may berefurbished on-site whenneeded, drastically reducingwaste of roong over thelife of a building. Products

with greater than 80% recycledcontent (largely post-consumer) areavailable.PROS: Highly durable some metal roofsinstalled in the 1800s are still inuse. Recyclable, and available withhigh post-consumer recycledcontent. Low maintenance costs. Lightweight useful for retrotsand seismic safety. Galvanized, painted, and coatedoptions are appropriate for rainwatecollection systems or growing edibleplants near downspouts. Excellent re resistance.CONS: Higher initial cost but typicallyoffers favorable life cycle cost. Manufacture is energy intensive- partially offset by durability/recyclability.

Recycled Content RoongHighly durable roongmaterials can be madefrom recycled rubbeand/or plastics, providingthe appearance of slate owood shakes/shingles whilekeeping waste materials

in productive use and out of thelandll.PROS: Durable, available with a 50-yea

warranty. Contains recycled post-industriarubber and plastics. Attractive, and with integral color,will retain its appearance over time. Lightweight, potentially reducingthe necessary size of roof rafters.

Fiber Cement Siding

Fiber cement siding andshingles consist of woodbers blended with cement.The result can be smoothor embedded with a fauxwood grain or texture. Itis available pre-primed

and/or pre-nished. Because its

components are non-toxic, ber-cement siding is a good alternativeto vinyl siding.PROS: Very durable with littlemaintenance (50+ year rating). Extremely resistant to pests androt. Non-combustible. Can ultimately be crushed,recycled, and coked back intocementCONS:

Currently not manufacturedfrom domestic wood sources.(Wood bers must withstand themanufacturing process and thealkalinity of cement.) Cement has high embodiedenergy. Requires specialized cutting tools.

Wood-plastic composite lumber may containup to 35% recycled plastic, combined with65% wood ber--which may be post-industrialrecycled content or virgin ber.

Photo courtesy of U.S. Plastic Lumber, Ltd.


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CONS: Products made from a mix ofplastic and rubber (including thisexample) may reduce waste, butcannot be recycled again at end ofuse. Some recycled rubber productsmade from tires can leach smallamounts of contaminants (such as

metals) into rainwater, which is notdesirable for rainwater collectionor growing edible plants near adownspout. No post-consumer recycledcontent

Recycled Cotton Insulation

Exposure to commonberglass insulation canirritate skin and lungs.Recycled cotton insulation,made primarily frompost-industrial denim, isone benign alternative.

Cellulose is a common alternativeinsulation material made fromrecycled newsprint.PROS: Thermal performance per inch isas good as berglass insulation. Better sound insulation per inchthan berglass. Non-irritating to skin/respiratorysystem; cotton may be installed withbare hands. Higher recycled content than most

berglass. Cotton and cellulose both havegood resistance to re, mold,insects, and rodents because ofborate treatment.CONS: Walls with poor moistureprotection may result in a portionof the borate treatment leachingout. However, proper wall designand assembly is essential with anyinsulation.

Spray Foam Insulation

Sprayed Polyisocyanurate/Polyurethane Foam (SPF) isinsulation that is sprayeddirectly into wall or roofcavities, expanding to llcracks and voids. Sprayedcementious foam (i.e. AirKrete) has many similarproperties.

PROS: Thermal performance per inch isbetter than berglass insulation. Acts as both insulation and vaporbarrier, making walls resistant tocondensation and mold. Approvedfor insulating unvented roofs. Does not offgas once installedBlowing agents do not damage

ozone or contribute to greenhouseeffect. Good re resistance Durable, and can increase shearesistance values.CONS: Hazardous during installationrequires trained professionals. Some SPF is partly made fromrenewable soybeans, but thisexample is derived from petroleumproducts. Not recyclable but can becompacted.

High Efciency Windows

Windows and skylightsprovide light, viewsventilation, and can helpcapture solar heat. Lookfor Energy Star labeledwindows and windows

with an NFRC rated U-Factor of 0.4

or less for windows and 0.6 or lessfor skylights. Consider berglasswindow frames, which offer a goodcombination of low maintenancedurability, and insulation.PROS: High quality windows last fodecades, help maintain comfortabletemperatures, and save energy. Superior acoustical insulationimproves comfort. Wide variety of architecturastyles. Single-pane windows beingreplaced may be reused forunheated spaces such as solarium ogreenhouses.CONS: Few new windows incorporatesignicant recycled content. Highly efcient options with thelowest life-cycle cost tend to have ahigher purchase cost.

50-Year Composition Roong

Durable, 50-Year ratedcomposition shinglesare made primarily fromasphalt and gravel. A light

color reduces heat gainduring summer monthsby reecting more solar

radiation than dark colors.PROS: Reduces waste and saves moneyover the life of the roof by delayingor eliminating re-roong. Saves resources - it takes aboutthe same materials and labor tomanufacture and install a 50-yearrated shingle as a 30-year shingle. Readily available and familiar toany local roong contractor.CONS: Composition roofs are difcult torecycle and typically end up in thelandll. May leach minute quantities ofnoxious chemicals, which is notdesirable for rainwater collectionor growing edible plants near adownspout. Higher initial cost than 30-yearshingles.

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High efciency windows maybe constructed with wood,metal, berglass, or vinyl sashmaterials. They will havedouble or triple pane glazingwith special coatings or gasll for increased efciency,which is especially importantwhen glazing an entire wall,as shown in this photo. Thesewindows also incorporatesome FSC certied wood.

Photo courtesy of Loewen Windows


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Recycled-ContentGypsum Wall Board

Gypsum board (commonlyreferred to by its proprietarynames drywall orsheetrock) is nearly puregypsum covered by paper. Itis the most common interior

wall nish due to its price,familiarity, and ease of installation.The paper facing is commonlymade from recycled newsprint, andmanufacturers are now offeringproducts incorporating recycledgypsum (derived from coal ash,)PROS: Identical to standard gypsumboard at no extra cost. Clean cutoffs can be pulverizedand used as a soil amendment.

Recyclable at the end of its usefullife. (But, this is rare due to the lowcost of virgin gypsum.)CONS: West coast manufacturers tendto offer lower recycled-contentproducts (


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more). Vertically laminated plywoodand ooring products consist of lay-ers of bamboo compressed with abinder, creating a durable, resilientnish material.PROS: Very rapidly renewable- conserves forest resources. Strong, hard, and di-

mensionally stable. Very durable - can last de-cades when well maintained.CONS: Cost can be high (thoughcomparable to hardwoods). Harvested/processed overseas;shipping increases embodied energy. Some products use urea formal-dehyde binders, which release smallquantities of formaldehyde.

Recycled-Content Carpet

2.5 million tons of carpet,typically manufacturedfrom virgin petroleum, isdiscarded each year. Byrecycling polyethylene(PET) into polyester carpetber, common plastics arediverted from the landll.Carpet with Nylon 6ber and backing is also

repeatedly recyclable into new

carpet. For a natural, biodegradableoption, consider wool, jute, sisal, orcoir.PROS: Costs and available colors ofrecycled and/or recyclable carpetsare comparable to standard carpets. Low-emitting carpets and paddingcertied by GreenGuard and/or theCarpet and Rug Institute (CRI GreenLabel), and installed with tack-stripor low-emitting adhesives, canimprove indoor air quality.

Selection of environmentallypreferable carpets is increasing.CONS: Recycled content may be


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Natural Wallcovering

Common vinyl-based wallcovering (e.g. wallpaper)can be a signicantsource of Volatile OrganicCompounds (VOCs),will produce both dioxinand hydrochloric acid in

the event of a re, and can leachphthalate plasticizers, which candisrupt hormonal functioning.Natural wall coverings, composedprimarily of plant-derived bers, area beautiful alternative.PROS: Durable and generally readilycleaned with non-toxic cleansers. Breathable and low or noemissions, reducing the likelihood ofmold, and helping indoor air quality

when applied with appropriateadhesives. Made from non-toxic components,and typically biodegradable at theend of their useful life.CONS: More expensive than vinyl,but better indoor air quality canpotentially yield a much lower life-cycle cost.

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High-Efciency Appliances

The cost of energy andwater an appliance usesis typically many timesits purchase cost. Whenbuying new appliances,look for the EPA Energy Starseal, or refer to AmericanCouncil for EnergyEfcient Economys freeindependent buyers guide

(www.aceee.org).PROS: Energy efciency not only saves

money, it reduces pollution andgreenhouse gas emissions. Efcient models perform as well orbetter than standard models. Reduced water consumption helpsstretch supplies and saves additionalenergy by reducing the amount ofpumping, treatment, and/or waterheating per load of dishes, laundry,etc. Utilities frequently offer rebates forefcient products.

CONS: Sometimes costs a little morethan comparable, less efcientappliances. Appliances that are efcient willstill waste energy and water if theyare oversized. Look for the right-sized option.

Solar PhotovoltaicsPhotovoltaic (PV) materials,such as the thin-lmproduct laminated directlyonto this metal roongsample, convert sunlightinto electricity. By addingphotovoltaics to the roofof your home or ofcebuilding, you can generateclean, renewable energy

and enjoy protection from rising

electricity costs.PROS: Reduced use of electricity from thegrid directly reduces greenhouse gasemissions. PV panels can provide most or allof the electricity needed for mosthomes, often even in fairly foggymicroclimates. Durable many panels installed inthe 1970s are still operating today. State and federal incentives canoffset the initial cost to install.

Excess electricity produced byyour PV system can be fed back intothe grid the utility company billsonly for net amount of power used.

Radiant Hydronic Heating

In radiant hydronic heatingsystems, hot water is pipedthrough the oor, warming

the room from belowThey are particularlyeffective when combinedwith passive solar designand help maintain steadycomfortable interiotemperatures when installed

in oors with high thermal mass.PROS: Highly efcient, may reduceheating costs by more than 30%Solar water heating can furthereduce energy use.

Improves indoor air quality byeliminating ducts and fans thaaccumulate and distribute dust andother allergens. Provides excellent comfortand keeps concrete or tiled oorscomfortably warm to the touch.CONS: May be more expensive thanforced air, depending on design. Durable piping is essential becauserepairing leaks can be difcult. Knowledgeable design is critical to

performance. Electric radiant systems aretypically less desirable thanhydronic.

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CONS: High initial cost but prices areincreasingly competitive.

Radiant heat-ing systemsprovide stable,comfor tab letemperatures,and will keeptypically coldconcrete ortiled oorswarm to thetouch. Theycan also helpimprove in-door air qual-ity over forcedair systems.

Photo courtesy ofWarmboard, Inc.

APA-rated tongue & groove plywoodbase also acts as structural suboor.

Aluminum layer conductsheat and allows for lowerwater temperatures.

1/2 PEX tubingat 12 centers

transports heatedwater through

the system.

A wide range of nish ooring materialsmay be installed, including tile, carpet,

wood, cork, or linoleum.

Protective paint


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9. Why Build Green